diff --git a/.idea/libraries/Dart_Packages.xml b/.idea/libraries/Dart_Packages.xml
index f058607..79be91e 100644
--- a/.idea/libraries/Dart_Packages.xml
+++ b/.idea/libraries/Dart_Packages.xml
@@ -2,273 +2,305 @@
   <library name="Dart Packages" type="DartPackagesLibraryType">
     <properties>
       <option name="packageNameToDirsMap">
+        <entry key="archive">
+          <value>
+            <list>
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/archive-2.0.13/lib" />
+            </list>
+          </value>
+        </entry>
+        <entry key="args">
+          <value>
+            <list>
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/args-1.6.0/lib" />
+            </list>
+          </value>
+        </entry>
         <entry key="async">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/async-2.0.8/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/async-2.5.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="boolean_selector">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/boolean_selector-1.0.4/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/boolean_selector-2.1.0-nullsafety.1/lib" />
+            </list>
+          </value>
+        </entry>
+        <entry key="characters">
+          <value>
+            <list>
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/characters-1.1.0-nullsafety.3/lib" />
             </list>
           </value>
         </entry>
         <entry key="charcode">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/charcode-1.1.2/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/charcode-1.2.0-nullsafety.1/lib" />
+            </list>
+          </value>
+        </entry>
+        <entry key="clock">
+          <value>
+            <list>
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/clock-1.1.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="collection">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/collection-1.14.11/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/collection-1.15.0-nullsafety.3/lib" />
             </list>
           </value>
         </entry>
         <entry key="convert">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/convert-2.1.1/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/convert-2.1.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="crypto">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/crypto-2.0.6/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/crypto-2.1.5/lib" />
             </list>
           </value>
         </entry>
         <entry key="cupertino_icons">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/cupertino_icons-0.1.2/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/cupertino_icons-0.1.3/lib" />
             </list>
           </value>
         </entry>
-        <entry key="file">
+        <entry key="fake_async">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/file-5.0.7/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/fake_async-1.2.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
-        <entry key="flutter">
+        <entry key="file">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/packages/flutter/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/file-6.0.0-nullsafety.2/lib" />
             </list>
           </value>
         </entry>
-        <entry key="flutter_driver">
+        <entry key="flutter">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/packages/flutter_driver/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/packages/flutter/lib" />
             </list>
           </value>
         </entry>
-        <entry key="flutter_test">
+        <entry key="flutter_driver">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/packages/flutter_test/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/packages/flutter_driver/lib" />
             </list>
           </value>
         </entry>
-        <entry key="fuchsia_remote_debug_protocol">
+        <entry key="flutter_test">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/packages/fuchsia_remote_debug_protocol/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/packages/flutter_test/lib" />
             </list>
           </value>
         </entry>
-        <entry key="intl">
+        <entry key="fuchsia_remote_debug_protocol">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/intl-0.15.7/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/packages/fuchsia_remote_debug_protocol/lib" />
             </list>
           </value>
         </entry>
         <entry key="json_rpc_2">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/json_rpc_2-2.0.9/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/json_rpc_2-2.2.2/lib" />
             </list>
           </value>
         </entry>
         <entry key="matcher">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/matcher-0.12.3+1/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/matcher-0.12.10-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="meta">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/meta-1.1.6/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.3/lib" />
             </list>
           </value>
         </entry>
         <entry key="path">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/path-1.6.2/lib" />
-            </list>
-          </value>
-        </entry>
-        <entry key="pedantic">
-          <value>
-            <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/pedantic-1.4.0/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="platform">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/platform-2.2.0/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/platform-3.0.0-nullsafety.2/lib" />
             </list>
           </value>
         </entry>
         <entry key="process">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/process-3.0.9/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/process-4.0.0-nullsafety.2/lib" />
             </list>
           </value>
         </entry>
         <entry key="pub_semver">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/pub_semver-1.4.2/lib" />
-            </list>
-          </value>
-        </entry>
-        <entry key="quiver">
-          <value>
-            <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/quiver-2.0.1/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/pub_semver-1.4.4/lib" />
             </list>
           </value>
         </entry>
         <entry key="sky_engine">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/bin/cache/pkg/sky_engine/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/bin/cache/pkg/sky_engine/lib" />
             </list>
           </value>
         </entry>
         <entry key="source_span">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/source_span-1.5.4/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/source_span-1.8.0-nullsafety.2/lib" />
             </list>
           </value>
         </entry>
         <entry key="stack_trace">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/stack_trace-1.9.3/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/stack_trace-1.10.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="stream_channel">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/stream_channel-1.6.8/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/stream_channel-2.1.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="string_scanner">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/string_scanner-1.0.4/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/string_scanner-1.1.0-nullsafety.1/lib" />
+            </list>
+          </value>
+        </entry>
+        <entry key="sync_http">
+          <value>
+            <list>
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/sync_http-0.2.0/lib" />
             </list>
           </value>
         </entry>
         <entry key="term_glyph">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/term_glyph-1.1.0/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/term_glyph-1.2.0-nullsafety.1/lib" />
             </list>
           </value>
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         <entry key="test_api">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/test_api-0.2.2/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/test_api-0.2.19-nullsafety.2/lib" />
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           </value>
         </entry>
         <entry key="typed_data">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/typed_data-1.1.6/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/typed_data-1.3.0-nullsafety.3/lib" />
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           </value>
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         <entry key="vector_math">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/vector_math-2.0.8/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/vector_math-2.1.0-nullsafety.3/lib" />
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         <entry key="vm_service_client">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/vm_service_client-0.2.6/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/vm_service_client-0.2.6+2/lib" />
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         <entry key="web_socket_channel">
           <value>
             <list>
-              <option value="$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/web_socket_channel-1.0.9/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/web_socket_channel-1.1.0/lib" />
+            </list>
+          </value>
+        </entry>
+        <entry key="webdriver">
+          <value>
+            <list>
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/webdriver-2.1.2/lib" />
             </list>
           </value>
         </entry>
       </option>
     </properties>
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-      <root url="file://$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/boolean_selector-1.0.4/lib" />
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-      <root url="file://$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/convert-2.1.1/lib" />
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-      <root url="file://$USER_HOME$/working/flutter/.pub-cache/hosted/pub.flutter-io.cn/cupertino_icons-0.1.2/lib" />
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-      <root url="file://$USER_HOME$/working/flutter/packages/fuchsia_remote_debug_protocol/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/archive-2.0.13/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/args-1.6.0/lib" />
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+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/characters-1.1.0-nullsafety.3/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/charcode-1.2.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/clock-1.1.0-nullsafety.1/lib" />
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+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/convert-2.1.1/lib" />
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+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety.1/lib" />
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+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/sync_http-0.2.0/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/term_glyph-1.2.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/test_api-0.2.19-nullsafety.2/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/typed_data-1.3.0-nullsafety.3/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/vector_math-2.1.0-nullsafety.3/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/vm_service_client-0.2.6+2/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/web_socket_channel-1.1.0/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/webdriver-2.1.2/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/pkg/sky_engine/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/packages/flutter/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/packages/flutter_driver/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/packages/flutter_test/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/packages/fuchsia_remote_debug_protocol/lib" />
     </CLASSES>
     <JAVADOC />
     <SOURCES />
diff --git a/.idea/libraries/Dart_SDK.xml b/.idea/libraries/Dart_SDK.xml
index 321b902..3aeef26 100644
--- a/.idea/libraries/Dart_SDK.xml
+++ b/.idea/libraries/Dart_SDK.xml
@@ -1,25 +1,27 @@
 <component name="libraryTable">
   <library name="Dart SDK">
     <CLASSES>
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/async" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/cli" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/collection" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/convert" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/core" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/developer" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/html" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/indexed_db" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/io" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/isolate" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/js" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/js_util" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/math" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/mirrors" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/svg" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/typed_data" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/web_audio" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/web_gl" />
-      <root url="file://$USER_HOME$/working/flutter/bin/cache/dart-sdk/lib/web_sql" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/async" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/cli" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/collection" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/convert" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/core" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/developer" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/ffi" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/html" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/indexed_db" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/io" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/isolate" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/js" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/js_util" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/math" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/mirrors" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/svg" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/typed_data" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/wasm" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/web_audio" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/web_gl" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/web_sql" />
     </CLASSES>
     <JAVADOC />
     <SOURCES />
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index acf13e6..9c30822 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -6,75 +6,12 @@
     </configurations>
   </component>
   <component name="ChangeListManager">
-    <list default="true" id="da615bec-bd21-494f-ae3e-e28a9fad9952" name="Default" comment="">
-      <change beforePath="$PROJECT_DIR$/.idea/libraries/Dart_Packages.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/libraries/Dart_Packages.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/CHANGELOG.md" beforeDir="false" afterPath="$PROJECT_DIR$/CHANGELOG.md" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/example/pubspec.lock" beforeDir="false" afterPath="$PROJECT_DIR$/example/pubspec.lock" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/lib/transformer_page_view.dart" beforeDir="false" afterPath="$PROJECT_DIR$/lib/transformer_page_view.dart" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/pubspec.lock" beforeDir="false" afterPath="$PROJECT_DIR$/pubspec.lock" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/pubspec.yaml" beforeDir="false" afterPath="$PROJECT_DIR$/pubspec.yaml" afterDir="false" />
-    </list>
-    <ignored path="$PROJECT_DIR$/.dart_tool/" />
-    <ignored path="$PROJECT_DIR$/.idea/" />
-    <ignored path="$PROJECT_DIR$/.pub/" />
-    <ignored path="$PROJECT_DIR$/build/" />
-    <option name="EXCLUDED_CONVERTED_TO_IGNORED" value="true" />
-    <option name="TRACKING_ENABLED" value="true" />
+    <list default="true" id="da615bec-bd21-494f-ae3e-e28a9fad9952" name="Default" comment="" />
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
     <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
     <option name="LAST_RESOLUTION" value="IGNORE" />
   </component>
-  <component name="FileEditorManager">
-    <leaf>
-      <file leaf-file-name="parallax.dart" pinned="false" current-in-tab="false">
-        <entry file="file://$PROJECT_DIR$/lib/parallax.dart">
-          <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="150">
-              <caret line="11" selection-start-line="11" selection-end-line="11" />
-            </state>
-          </provider>
-        </entry>
-      </file>
-      <file leaf-file-name="transformer_page_view.dart" pinned="false" current-in-tab="false">
-        <entry file="file://$PROJECT_DIR$/lib/transformer_page_view.dart">
-          <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="95">
-              <caret line="473" column="9" selection-start-line="473" selection-start-column="9" selection-end-line="473" selection-end-column="9" />
-            </state>
-          </provider>
-        </entry>
-      </file>
-      <file leaf-file-name="pubspec.yaml" pinned="false" current-in-tab="false">
-        <entry file="file://$PROJECT_DIR$/pubspec.yaml">
-          <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="30">
-              <caret line="2" column="14" selection-start-line="2" selection-start-column="14" selection-end-line="2" selection-end-column="14" />
-            </state>
-          </provider>
-        </entry>
-      </file>
-      <file leaf-file-name="CHANGELOG.md" pinned="false" current-in-tab="true">
-        <entry file="file://$PROJECT_DIR$/CHANGELOG.md">
-          <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="30">
-              <caret line="2" column="43" selection-start-line="2" selection-start-column="43" selection-end-line="2" selection-end-column="43" />
-            </state>
-          </provider>
-        </entry>
-      </file>
-      <file leaf-file-name="framework.dart" pinned="false" current-in-tab="false">
-        <entry file="file://$USER_HOME$/working/flutter/packages/flutter/lib/src/widgets/framework.dart">
-          <provider selected="true" editor-type-id="text-editor">
-            <state relative-caret-position="981">
-              <caret line="1137" column="30" selection-start-line="1137" selection-start-column="30" selection-end-line="1137" selection-end-column="30" />
-            </state>
-          </provider>
-        </entry>
-      </file>
-    </leaf>
-  </component>
   <component name="FileTemplateManagerImpl">
     <option name="RECENT_TEMPLATES">
       <list>
@@ -82,128 +19,27 @@
       </list>
     </option>
   </component>
-  <component name="FindInProjectRecents">
-    <findStrings>
-      <find>viewportDimension</find>
-      <find>_page</find>
-      <find>_constraints</find>
-      <find>SliverConstraints</find>
-      <find>_renderObject</find>
-      <find>SliverMultiBoxAdaptorParentData</find>
-      <find>MySliverFillViewport</find>
-      <find>RenderSliverMultiBoxAdaptor</find>
-      <find>offset</find>
-      <find>print</find>
-      <find>curve</find>
-      <find>_currentPixels</find>
-      <find>reverse</find>
-      <find>onChangeNotifier</find>
-      <find>index_controller</find>
-      <find>_pageController</find>
-      <find>_buildItem</find>
-      <find>Random</find>
-      <find>children</find>
-      <find>next</find>
-      <find>loop</find>
-      <find>itemCount</find>
-      <find>3</find>
-      <find>dispose</find>
-      <find>didUpdateWidget</find>
-      <find>isNotEmpty</find>
-      <find>viewportFraction</find>
-      <find>_size</find>
-      <find>findRenderObject</find>
-      <find>setState</find>
-    </findStrings>
-    <replaceStrings>
-      <replace>transformer_page_view</replace>
-    </replaceStrings>
-  </component>
   <component name="Git.Settings">
     <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$" />
   </component>
-  <component name="IdeDocumentHistory">
-    <option name="CHANGED_PATHS">
-      <list>
-        <option value="$PROJECT_DIR$/dev/bots/travis_install.sh" />
-        <option value="$PROJECT_DIR$/example/lib/ThreeD.dart" />
-        <option value="$PROJECT_DIR$/example/lib/DepthPageTransformer.dart" />
-        <option value="$PROJECT_DIR$/example/test/widget_test.dart" />
-        <option value="$PROJECT_DIR$/.gitignore" />
-        <option value="$PROJECT_DIR$/example/lib/WelcomeView.dart" />
-        <option value="$PROJECT_DIR$/example/pubspec.yaml" />
-        <option value="$PROJECT_DIR$/example/lib/diary.dart" />
-        <option value="$PROJECT_DIR$/lib/parallax.dart" />
-        <option value="$PROJECT_DIR$/example/lib/welcome.dart" />
-        <option value="$PROJECT_DIR$/example/lib/images.dart" />
-        <option value="$PROJECT_DIR$/example/lib/DeepthPageTransformer.dart" />
-        <option value="$PROJECT_DIR$/example/lib/ZoomInPageTransformer.dart" />
-        <option value="$PROJECT_DIR$/example/lib/ZoomOutPageTransformer.dart" />
-        <option value="$PROJECT_DIR$/example/lib/ThreeDTransformer.dart" />
-        <option value="$PROJECT_DIR$/example/lib/FixlistTest.dart" />
-        <option value="$PROJECT_DIR$/example/lib/AccordionTransformer.dart" />
-        <option value="$PROJECT_DIR$/lib/transformers.dart" />
-        <option value="$PROJECT_DIR$/example/lib/ScaleAndFadeTransformer.dart" />
-        <option value="$PROJECT_DIR$/example/lib/buildin_transformers.dart" />
-        <option value="$PROJECT_DIR$/README.md" />
-        <option value="$PROJECT_DIR$/example/lib/zero.dart" />
-        <option value="$PROJECT_DIR$/lib/index_controller.dart" />
-        <option value="$PROJECT_DIR$/example/lib/main.dart" />
-        <option value="$PROJECT_DIR$/example/lib/screens/ProductDetailView.dart" />
-        <option value="$PROJECT_DIR$/example/lib/CachePageView.dart" />
-        <option value="$PROJECT_DIR$/test/transformer_page_view_test.dart" />
-        <option value="$PROJECT_DIR$/example/lib/screens/ProductListView.dart" />
-        <option value="$PROJECT_DIR$/lib/transformer_page_view.dart" />
-        <option value="$PROJECT_DIR$/pubspec.yaml" />
-        <option value="$PROJECT_DIR$/CHANGELOG.md" />
-      </list>
-    </option>
-  </component>
-  <component name="ProjectFrameBounds">
-    <option name="x" value="100" />
-    <option name="y" value="93" />
-    <option name="width" value="1397" />
-    <option name="height" value="877" />
-  </component>
+  <component name="ProjectId" id="1qWLErRpWi79E1B5O87e5Bp3LeF" />
   <component name="ProjectLevelVcsManager">
     <ConfirmationsSetting value="2" id="Add" />
   </component>
-  <component name="ProjectView">
-    <navigator currentView="ProjectPane" proportions="" version="1">
-      <foldersAlwaysOnTop value="true" />
-    </navigator>
-    <panes>
-      <pane id="ProjectPane">
-        <subPane>
-          <expand>
-            <path>
-              <item name="transformer_page_view" type="b2602c69:ProjectViewProjectNode" />
-              <item name="transformer_page_view" type="462c0819:PsiDirectoryNode" />
-            </path>
-            <path>
-              <item name="transformer_page_view" type="b2602c69:ProjectViewProjectNode" />
-              <item name="transformer_page_view" type="462c0819:PsiDirectoryNode" />
-              <item name="lib" type="462c0819:PsiDirectoryNode" />
-            </path>
-          </expand>
-          <select />
-        </subPane>
-        <option name="show-excluded-files" value="false" />
-      </pane>
-      <pane id="Scope" />
-      <pane id="AndroidView" />
-      <pane id="PackagesPane" />
-    </panes>
+  <component name="ProjectViewState">
+    <option name="showLibraryContents" value="true" />
   </component>
   <component name="PropertiesComponent">
+    <property name="ASKED_ADD_EXTERNAL_FILES" value="true" />
     <property name="com.android.tools.idea.instantapp.provision.ProvisionBeforeRunTaskProvider.myTimeStamp" value="1539840281539" />
     <property name="dart.analysis.tool.window.force.activate" value="false" />
+    <property name="dart.analysis.tool.window.visible" value="false" />
     <property name="io.flutter.reload.alreadyRun" value="true" />
     <property name="last_opened_file_path" value="$PROJECT_DIR$" />
     <property name="project.structure.last.edited" value="Modules" />
     <property name="project.structure.proportion" value="0.0" />
     <property name="project.structure.side.proportion" value="0.0" />
-    <property name="settings.editor.selected.configurable" value="dart.settings" />
+    <property name="settings.editor.selected.configurable" value="flutter.settings" />
     <property name="show.migrate.to.gradle.popup" value="false" />
   </component>
   <component name="RecentsManager">
@@ -214,20 +50,25 @@
       <recent name="C:\Users\Administrator\AndroidStudioProjects\transformer_page_view\example\assets" />
     </key>
   </component>
-  <component name="RunDashboard">
-    <option name="ruleStates">
-      <list>
-        <RuleState>
-          <option name="name" value="ConfigurationTypeDashboardGroupingRule" />
-        </RuleState>
-        <RuleState>
-          <option name="name" value="StatusDashboardGroupingRule" />
-        </RuleState>
-      </list>
-    </option>
-  </component>
   <component name="RunManager" selected="Flutter.main.dart">
-    <configuration default="true" type="AndroidJUnit" factoryName="Android JUnit">
+    <configuration name="&lt;template&gt;" type="Applet" default="true" selected="false">
+      <option name="MAIN_CLASS_NAME" />
+      <option name="HTML_FILE_NAME" />
+      <option name="HTML_USED" value="false" />
+      <option name="WIDTH" value="400" />
+      <option name="HEIGHT" value="300" />
+      <option name="POLICY_FILE" value="$APPLICATION_HOME_DIR$/bin/appletviewer.policy" />
+      <option name="VM_PARAMETERS" />
+    </configuration>
+    <configuration name="&lt;template&gt;" type="JUnit" default="true" selected="false">
+      <option name="MAIN_CLASS_NAME" />
+      <option name="VM_PARAMETERS" value="-ea" />
+      <option name="PARAMETERS" />
+      <option name="WORKING_DIRECTORY" value="$MODULE_DIR$" />
+    </configuration>
+    <configuration default="true" type="JUnit" factoryName="JUnit">
+      <extension name="coverage" enabled="false" merge="false" sample_coverage="true" runner="idea" />
+      <module name="" />
       <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
       <option name="ALTERNATIVE_JRE_PATH" />
       <option name="PACKAGE_NAME" />
@@ -237,17 +78,33 @@
       <option name="VM_PARAMETERS" />
       <option name="PARAMETERS" />
       <option name="WORKING_DIRECTORY" />
+      <option name="ENV_VARIABLES" />
       <option name="PASS_PARENT_ENVS" value="true" />
       <option name="TEST_SEARCH_SCOPE">
         <value defaultName="singleModule" />
       </option>
+      <envs />
       <patterns />
+      <method />
+    </configuration>
+    <configuration name="&lt;template&gt;" type="#org.jetbrains.idea.devkit.run.PluginConfigurationType" default="true" selected="false">
+      <option name="VM_PARAMETERS" value="-Xmx512m -Xms256m -XX:MaxPermSize=250m -ea" />
+    </configuration>
+    <configuration default="true" type="AndroidJUnit" factoryName="Android JUnit">
+      <option name="TEST_OBJECT" value="class" />
+      <option name="VM_PARAMETERS" />
+      <option name="WORKING_DIRECTORY" />
+      <method v="2">
+        <option name="Make" enabled="true" />
+      </method>
     </configuration>
     <configuration default="true" type="AndroidRunConfigurationType" factoryName="Android App">
       <option name="DEPLOY" value="true" />
       <option name="DEPLOY_APK_FROM_BUNDLE" value="false" />
+      <option name="DEPLOY_AS_INSTANT" value="false" />
       <option name="ARTIFACT_NAME" value="" />
       <option name="PM_INSTALL_OPTIONS" value="" />
+      <option name="ALL_USERS" value="false" />
       <option name="DYNAMIC_FEATURES_DISABLED_LIST" value="" />
       <option name="ACTIVITY_EXTRA_FLAGS" value="" />
       <option name="MODE" value="default_activity" />
@@ -256,8 +113,6 @@
       <option name="SKIP_NOOP_APK_INSTALLATIONS" value="true" />
       <option name="FORCE_STOP_RUNNING_APP" value="true" />
       <option name="TARGET_SELECTION_MODE" value="SHOW_DIALOG" />
-      <option name="USE_LAST_SELECTED_DEVICE" value="false" />
-      <option name="PREFERRED_AVD" value="" />
       <option name="SELECTED_CLOUD_MATRIX_CONFIGURATION_ID" value="-1" />
       <option name="SELECTED_CLOUD_MATRIX_PROJECT_ID" value="" />
       <option name="DEBUGGER_TYPE" value="Auto" />
@@ -285,29 +140,31 @@
       </Native>
       <Profilers>
         <option name="ADVANCED_PROFILING_ENABLED" value="false" />
+        <option name="STARTUP_PROFILING_ENABLED" value="false" />
         <option name="STARTUP_CPU_PROFILING_ENABLED" value="false" />
         <option name="STARTUP_CPU_PROFILING_CONFIGURATION_NAME" value="Sampled (Java)" />
+        <option name="STARTUP_NATIVE_MEMORY_PROFILING_ENABLED" value="false" />
+        <option name="NATIVE_MEMORY_SAMPLE_RATE_BYTES" value="2048" />
       </Profilers>
       <option name="DEEP_LINK" value="" />
       <option name="ACTIVITY_CLASS" value="" />
-      <method>
-        <option name="Android.Gradle.BeforeRunTask" enabled="true" />
-      </method>
+      <option name="SEARCH_ACTIVITY_IN_GLOBAL_SCOPE" value="false" />
+      <option name="SKIP_ACTIVITY_VALIDATION" value="false" />
+      <method v="2" />
     </configuration>
     <configuration default="true" type="AndroidTestRunConfigurationType" factoryName="Android Instrumented Tests">
       <option name="TESTING_TYPE" value="0" />
-      <option name="INSTRUMENTATION_RUNNER_CLASS" value="" />
       <option name="METHOD_NAME" value="" />
       <option name="CLASS_NAME" value="" />
       <option name="PACKAGE_NAME" value="" />
+      <option name="INSTRUMENTATION_RUNNER_CLASS" value="" />
       <option name="EXTRA_OPTIONS" value="" />
+      <option name="INCLUDE_GRADLE_EXTRA_OPTIONS" value="true" />
       <option name="CLEAR_LOGCAT" value="false" />
       <option name="SHOW_LOGCAT_AUTOMATICALLY" value="false" />
       <option name="SKIP_NOOP_APK_INSTALLATIONS" value="true" />
       <option name="FORCE_STOP_RUNNING_APP" value="true" />
       <option name="TARGET_SELECTION_MODE" value="SHOW_DIALOG" />
-      <option name="USE_LAST_SELECTED_DEVICE" value="false" />
-      <option name="PREFERRED_AVD" value="" />
       <option name="SELECTED_CLOUD_MATRIX_CONFIGURATION_ID" value="-1" />
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@@ -335,29 +192,37 @@
       </Native>
       <Profilers>
         <option name="ADVANCED_PROFILING_ENABLED" value="false" />
+        <option name="STARTUP_PROFILING_ENABLED" value="false" />
         <option name="STARTUP_CPU_PROFILING_ENABLED" value="false" />
         <option name="STARTUP_CPU_PROFILING_CONFIGURATION_NAME" value="Sampled (Java)" />
+        <option name="STARTUP_NATIVE_MEMORY_PROFILING_ENABLED" value="false" />
+        <option name="NATIVE_MEMORY_SAMPLE_RATE_BYTES" value="2048" />
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+      <method v="2" />
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       <option name="WORKING_DIRECTORY" value="$PROJECT_DIR$" />
+      <method v="2">
+        <option name="Make" enabled="true" />
+      </method>
     </configuration>
     <configuration name="images.dart" type="FlutterRunConfigurationType" factoryName="Flutter" nameIsGenerated="true">
       <option name="filePath" value="$PROJECT_DIR$/example/lib/images.dart" />
+      <method v="2" />
     </configuration>
     <configuration name="main.dart" type="FlutterRunConfigurationType" factoryName="Flutter">
       <option name="filePath" value="$PROJECT_DIR$/example/lib/main.dart" />
+      <method v="2" />
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     <configuration name="welcome.dart" type="FlutterRunConfigurationType" factoryName="Flutter" nameIsGenerated="true">
       <option name="filePath" value="$PROJECT_DIR$/example/lib/welcome.dart" />
+      <method v="2" />
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       <option name="testFile" value="$PROJECT_DIR$/test/transformer_page_view_test.dart" />
+      <method v="2" />
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@@ -387,67 +252,18 @@
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       <option name="MAIN_CLASS_NAME" />
       <option name="WORKING_DIRECTORY" />
+      <method v="2">
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-      <option name="PACKAGE_NAME" />
-      <option name="MAIN_CLASS_NAME" />
-      <option name="METHOD_NAME" />
-      <option name="GROUP_NAME" />
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@@ -500,41 +316,34 @@
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-          <caret line="305" column="10" selection-start-line="305" selection-start-column="10" selection-end-line="305" selection-end-column="10" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/example/lib/zero.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="120">
-          <caret line="8" column="34" lean-forward="true" selection-start-line="8" selection-start-column="34" selection-end-line="8" selection-end-column="34" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/pubspec.lock">
-      <provider selected="true" editor-type-id="text-editor">
-        <state />
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/example/pubspec.yaml">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="30">
-          <caret line="2" selection-start-line="2" selection-end-line="2" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/lib/index_controller.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="105">
-          <caret line="7" column="34" selection-start-line="7" selection-start-column="34" selection-end-line="7" selection-end-column="34" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/example/lib/AccordionTransformer.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="480">
-          <caret line="37" column="11" selection-start-line="37" selection-start-column="11" selection-end-line="37" selection-end-column="11" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$USER_HOME$/working/flutter/packages/flutter/lib/src/material/page.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="154">
-          <caret line="43" column="2" selection-start-line="43" selection-start-column="2" selection-end-line="43" selection-end-column="2" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/example/lib/screens/ProductDetailView.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state>
-          <caret column="7" selection-start-column="7" selection-end-column="7" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/example/lib/CachePageView.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="-41">
-          <caret line="80" column="6" selection-start-line="80" selection-start-column="6" selection-end-line="80" selection-end-column="6" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/test/transformer_page_view_test.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state>
-          <caret column="39" selection-start-column="39" selection-end-column="39" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/example/lib/images.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="184">
-          <caret line="52" column="36" selection-start-line="52" selection-start-column="36" selection-end-line="52" selection-end-column="36" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/example/lib/screens/ProductListView.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="208">
-          <caret line="29" column="37" selection-start-line="29" selection-start-column="37" selection-end-line="29" selection-end-column="37" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/example/lib/main.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="812">
-          <caret line="98" column="34" selection-start-line="98" selection-start-column="34" selection-end-line="98" selection-end-column="34" />
-          <folding>
-            <element signature="e#0#51#0" expanded="true" />
-          </folding>
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$USER_HOME$/working/flutter/packages/flutter/lib/src/rendering/object.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="31305">
-          <caret line="2106" column="6" selection-start-line="2106" selection-start-column="2" selection-end-line="2106" selection-end-column="6" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/README.md">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="525">
-          <caret line="35" column="6" selection-start-line="35" selection-start-column="6" selection-end-line="35" selection-end-column="6" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/lib/parallax.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="150">
-          <caret line="11" selection-start-line="11" selection-end-line="11" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$USER_HOME$/working/flutter/packages/flutter/lib/src/widgets/framework.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="981">
-          <caret line="1137" column="30" selection-start-line="1137" selection-start-column="30" selection-end-line="1137" selection-end-column="30" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/lib/transformer_page_view.dart">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="95">
-          <caret line="473" column="9" selection-start-line="473" selection-start-column="9" selection-end-line="473" selection-end-column="9" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/pubspec.yaml">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="30">
-          <caret line="2" column="14" selection-start-line="2" selection-start-column="14" selection-end-line="2" selection-end-column="14" />
-        </state>
-      </provider>
-    </entry>
-    <entry file="file://$PROJECT_DIR$/CHANGELOG.md">
-      <provider selected="true" editor-type-id="text-editor">
-        <state relative-caret-position="30">
-          <caret line="2" column="43" selection-start-line="2" selection-start-column="43" selection-end-line="2" selection-end-column="43" />
-        </state>
-      </provider>
-    </entry>
-  </component>
   <component name="masterDetails">
     <states>
       <state key="ArtifactsStructureConfigurable.UI">
diff --git a/example/android/app/build.gradle b/example/android/app/build.gradle
index 10e1482..3c3e30c 100644
--- a/example/android/app/build.gradle
+++ b/example/android/app/build.gradle
@@ -25,7 +25,7 @@ apply plugin: 'com.android.application'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion 28
 
     lintOptions {
         disable 'InvalidPackage'
@@ -35,10 +35,10 @@ android {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "com.yourcompany.example"
         minSdkVersion 16
-        targetSdkVersion 27
+        targetSdkVersion 28
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
 
     buildTypes {
@@ -56,6 +56,6 @@ flutter {
 
 dependencies {
     testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'com.android.support.test:runner:1.0.2'
-    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
+    androidTestImplementation 'androidx.test:runner:1.1.0'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0'
 }
diff --git a/example/android/app/src/main/AndroidManifest.xml b/example/android/app/src/main/AndroidManifest.xml
index 6dc50e8..f305c66 100644
--- a/example/android/app/src/main/AndroidManifest.xml
+++ b/example/android/app/src/main/AndroidManifest.xml
@@ -27,13 +27,23 @@
                  until Flutter renders its first frame. It can be removed if
                  there is no splash screen (such as the default splash screen
                  defined in @style/LaunchTheme). -->
-            <meta-data
-                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
-                android:value="true" />
+            <meta-data android:name="io.flutter.embedding.android.NormalTheme" android:resource="@style/NormalTheme"/>
+            <!--  Displays an Android View that continues showing the launch screen
+                             Drawable until Flutter paints its first frame, then this splash
+                             screen fades out. A splash screen is useful to avoid any visual
+                             gap between the end of Android's launch screen and the painting of
+                             Flutter's first frame.  -->
+            <meta-data android:name="io.flutter.embedding.android.SplashScreenDrawable" android:resource="@drawable/launch_background"/>
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
+
+
+        <meta-data
+            android:name="flutterEmbedding"
+            android:value="2" />
+
     </application>
 </manifest>
diff --git a/example/android/app/src/main/java/com/yourcompany/example/MainActivity.java b/example/android/app/src/main/java/com/yourcompany/example/MainActivity.java
index 95c17bd..83756b9 100644
--- a/example/android/app/src/main/java/com/yourcompany/example/MainActivity.java
+++ b/example/android/app/src/main/java/com/yourcompany/example/MainActivity.java
@@ -1,13 +1,11 @@
 package com.yourcompany.example;
 
 import android.os.Bundle;
-import io.flutter.app.FlutterActivity;
-import io.flutter.plugins.GeneratedPluginRegistrant;
+import io.flutter.embedding.android.FlutterActivity;
 
 public class MainActivity extends FlutterActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
-    GeneratedPluginRegistrant.registerWith(this);
   }
 }
diff --git a/example/android/app/src/main/res/values/styles.xml b/example/android/app/src/main/res/values/styles.xml
index 00fa441..723556d 100644
--- a/example/android/app/src/main/res/values/styles.xml
+++ b/example/android/app/src/main/res/values/styles.xml
@@ -5,4 +5,7 @@
              Flutter draws its first frame -->
         <item name="android:windowBackground">@drawable/launch_background</item>
     </style>
+    <style name="NormalTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <item name="android:windowBackground">@android:color/white</item>
+    </style>
 </resources>
diff --git a/example/android/gradle.properties b/example/android/gradle.properties
index 8bd86f6..a5965ab 100644
--- a/example/android/gradle.properties
+++ b/example/android/gradle.properties
@@ -1 +1,4 @@
 org.gradle.jvmargs=-Xmx1536M
+android.enableR8=true
+android.useAndroidX=true
+android.enableJetifier=true
\ No newline at end of file
diff --git a/example/ios/Flutter/flutter_export_environment.sh b/example/ios/Flutter/flutter_export_environment.sh
new file mode 100755
index 0000000..e561ebb
--- /dev/null
+++ b/example/ios/Flutter/flutter_export_environment.sh
@@ -0,0 +1,15 @@
+#!/bin/sh
+# This is a generated file; do not edit or check into version control.
+export "FLUTTER_ROOT=/home/faiyyaz/snap/flutter/common/flutter"
+export "FLUTTER_APPLICATION_PATH=/home/faiyyaz/AndroidStudioProjects/transformer_page_view/example"
+export "FLUTTER_TARGET=lib/main.dart"
+export "FLUTTER_BUILD_DIR=build"
+export "SYMROOT=${SOURCE_ROOT}/../build/ios"
+export "OTHER_LDFLAGS=$(inherited) -framework Flutter"
+export "FLUTTER_FRAMEWORK_DIR=/home/faiyyaz/snap/flutter/common/flutter/bin/cache/artifacts/engine/ios"
+export "FLUTTER_BUILD_NAME=1.0.0"
+export "FLUTTER_BUILD_NUMBER=1"
+export "DART_OBFUSCATION=false"
+export "TRACK_WIDGET_CREATION=false"
+export "TREE_SHAKE_ICONS=false"
+export "PACKAGE_CONFIG=.packages"
diff --git a/example/lib/CachePageView.dart b/example/lib/CachePageView.dart
index a6fbf2e..b9c77a1 100644
--- a/example/lib/CachePageView.dart
+++ b/example/lib/CachePageView.dart
@@ -78,6 +78,7 @@ const PageScrollPhysics _kPagePhysics = PageScrollPhysics();
 
 class Ext extends PageView {}
 
+// ignore: must_be_immutable
 class MyPageView extends StatelessWidget {
   final SliverChildListDelegate childrenDelegate;
 
diff --git a/example/lib/screens/ProductDetailView.dart b/example/lib/screens/ProductDetailView.dart
index 120718c..07423a8 100644
--- a/example/lib/screens/ProductDetailView.dart
+++ b/example/lib/screens/ProductDetailView.dart
@@ -1,8 +1,5 @@
-import 'package:example/buildin_transformers.dart';
 import 'package:flutter/material.dart';
 
-import 'package:transformer_page_view/transformer_page_view.dart';
-
 class ProductDetailView extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
diff --git a/example/pubspec.lock b/example/pubspec.lock
index c6f118f..86fd1c7 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -1,41 +1,62 @@
 # Generated by pub
-# See https://www.dartlang.org/tools/pub/glossary#lockfile
+# See https://dart.dev/tools/pub/glossary#lockfile
 packages:
   async:
     dependency: transitive
     description:
       name: async
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.8"
+    version: "2.5.0-nullsafety.1"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "2.1.0-nullsafety.1"
+  characters:
+    dependency: transitive
+    description:
+      name: characters
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.0-nullsafety.3"
   charcode:
     dependency: transitive
     description:
       name: charcode
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0-nullsafety.1"
+  clock:
+    dependency: transitive
+    description:
+      name: clock
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.2"
+    version: "1.1.0-nullsafety.1"
   collection:
     dependency: transitive
     description:
       name: collection
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.14.11"
+    version: "1.15.0-nullsafety.3"
   cupertino_icons:
     dependency: "direct main"
     description:
       name: cupertino_icons
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.2"
+    version: "0.1.3"
+  fake_async:
+    dependency: transitive
+    description:
+      name: fake_async
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0-nullsafety.1"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -50,37 +71,23 @@ packages:
     dependency: transitive
     description:
       name: matcher
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.3+1"
+    version: "0.12.10-nullsafety.1"
   meta:
     dependency: transitive
     description:
       name: meta
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0-nullsafety.3"
   path:
     dependency: transitive
     description:
       name: path
-      url: "https://pub.flutter-io.cn"
-    source: hosted
-    version: "1.6.2"
-  pedantic:
-    dependency: transitive
-    description:
-      name: pedantic
-      url: "https://pub.flutter-io.cn"
-    source: hosted
-    version: "1.4.0"
-  quiver:
-    dependency: transitive
-    description:
-      name: quiver
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.1"
+    version: "1.8.0-nullsafety.1"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -90,44 +97,44 @@ packages:
     dependency: transitive
     description:
       name: source_span
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.5.4"
+    version: "1.8.0-nullsafety.2"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.3"
+    version: "1.10.0-nullsafety.1"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.8"
+    version: "2.1.0-nullsafety.1"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "1.1.0-nullsafety.1"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0-nullsafety.1"
   test_api:
     dependency: transitive
     description:
       name: test_api
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.2"
+    version: "0.2.19-nullsafety.2"
   transformer_page_view:
     dependency: "direct dev"
     description:
@@ -139,15 +146,15 @@ packages:
     dependency: transitive
     description:
       name: typed_data
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0-nullsafety.3"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.8"
+    version: "2.1.0-nullsafety.3"
 sdks:
-  dart: ">=2.1.0 <3.0.0"
+  dart: ">=2.10.0-110 <2.11.0"
diff --git a/lib/transformer_page_view.dart b/lib/transformer_page_view.dart
index f4bc33f..ffdfe89 100644
--- a/lib/transformer_page_view.dart
+++ b/lib/transformer_page_view.dart
@@ -452,28 +452,29 @@ class _TransformerPageViewState extends State<TransformerPageView> {
 
   void _onGetSize(_) {
     Size size;
-    if (context == null) {
-      onGetSize(size);
-      return;
-    }
-    RenderObject renderObject = context.findRenderObject();
-    if (renderObject != null) {
-      Rect bounds = renderObject.paintBounds;
-      if (bounds != null) {
-        size = bounds.size;
+    if (mounted) {
+      if (context == null) {
+        onGetSize(size);
+        return;
       }
+      RenderObject renderObject = context.findRenderObject();
+      if (renderObject != null) {
+        Rect bounds = renderObject.paintBounds;
+        if (bounds != null) {
+          size = bounds.size;
+        }
+      }
+      _calcCurrentPixels();
+      onGetSize(size);
     }
-    _calcCurrentPixels();
-    onGetSize(size);
   }
 
   void onGetSize(Size size) {
-    if(mounted){
+    if (mounted) {
       setState(() {
         _size = size;
       });
     }
-
   }
 
   @override
diff --git a/pubspec.lock b/pubspec.lock
index 331b288..ff010fb 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -1,55 +1,90 @@
 # Generated by pub
-# See https://www.dartlang.org/tools/pub/glossary#lockfile
+# See https://dart.dev/tools/pub/glossary#lockfile
 packages:
+  archive:
+    dependency: transitive
+    description:
+      name: archive
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.0.13"
+  args:
+    dependency: transitive
+    description:
+      name: args
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.6.0"
   async:
     dependency: transitive
     description:
       name: async
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.8"
+    version: "2.5.0-nullsafety.1"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.1.0-nullsafety.1"
+  characters:
+    dependency: transitive
+    description:
+      name: characters
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "1.1.0-nullsafety.3"
   charcode:
     dependency: transitive
     description:
       name: charcode
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0-nullsafety.1"
+  clock:
+    dependency: transitive
+    description:
+      name: clock
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.2"
+    version: "1.1.0-nullsafety.1"
   collection:
     dependency: transitive
     description:
       name: collection
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.14.11"
+    version: "1.15.0-nullsafety.3"
   convert:
     dependency: transitive
     description:
       name: convert
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.1"
   crypto:
     dependency: transitive
     description:
       name: crypto
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.6"
+    version: "2.1.5"
+  fake_async:
+    dependency: transitive
+    description:
+      name: fake_async
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.2.0-nullsafety.1"
   file:
     dependency: transitive
     description:
       name: file
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "5.0.7"
+    version: "6.0.0-nullsafety.2"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -70,76 +105,55 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
-  intl:
-    dependency: transitive
-    description:
-      name: intl
-      url: "https://pub.flutter-io.cn"
-    source: hosted
-    version: "0.15.7"
   json_rpc_2:
     dependency: transitive
     description:
       name: json_rpc_2
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.9"
+    version: "2.2.2"
   matcher:
     dependency: transitive
     description:
       name: matcher
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.3+1"
+    version: "0.12.10-nullsafety.1"
   meta:
     dependency: transitive
     description:
       name: meta
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0-nullsafety.3"
   path:
     dependency: transitive
     description:
       name: path
-      url: "https://pub.flutter-io.cn"
-    source: hosted
-    version: "1.6.2"
-  pedantic:
-    dependency: transitive
-    description:
-      name: pedantic
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.4.0"
+    version: "1.8.0-nullsafety.1"
   platform:
     dependency: transitive
     description:
       name: platform
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.2.0"
+    version: "3.0.0-nullsafety.2"
   process:
     dependency: transitive
     description:
       name: process
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "3.0.9"
+    version: "4.0.0-nullsafety.2"
   pub_semver:
     dependency: transitive
     description:
       name: pub_semver
-      url: "https://pub.flutter-io.cn"
-    source: hosted
-    version: "1.4.2"
-  quiver:
-    dependency: transitive
-    description:
-      name: quiver
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.1"
+    version: "1.4.4"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -149,71 +163,85 @@ packages:
     dependency: transitive
     description:
       name: source_span
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.5.4"
+    version: "1.8.0-nullsafety.2"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.9.3"
+    version: "1.10.0-nullsafety.1"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.6.8"
+    version: "2.1.0-nullsafety.1"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.4"
+    version: "1.1.0-nullsafety.1"
+  sync_http:
+    dependency: transitive
+    description:
+      name: sync_http
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.2.0"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0-nullsafety.1"
   test_api:
     dependency: transitive
     description:
       name: test_api
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.2"
+    version: "0.2.19-nullsafety.2"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0-nullsafety.3"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.8"
+    version: "2.1.0-nullsafety.3"
   vm_service_client:
     dependency: transitive
     description:
       name: vm_service_client
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.2.6"
+    version: "0.2.6+2"
   web_socket_channel:
     dependency: transitive
     description:
       name: web_socket_channel
-      url: "https://pub.flutter-io.cn"
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.1.0"
+  webdriver:
+    dependency: transitive
+    description:
+      name: webdriver
+      url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.0.9"
+    version: "2.1.2"
 sdks:
-  dart: ">=2.1.0 <3.0.0"
+  dart: ">=2.10.0-110 <2.11.0"