feat: add face in

app_widget/analysis_options.yaml

@@ -1,2 +1,6 @@
 # tekartik flutter recommended lints (extension over google lints and pedantic)
-include: package:tekartik_lints_flutter/strict.yaml
+include: package:tekartik_lints_flutter/package.yaml
+
+linter:
+  rules:
+    public_member_api_docs: false

app_widget/lib/src/confirm_dialog.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 
+/// A simple dialog button
 class DialogButton extends StatelessWidget {
   final String text;
   final VoidCallback onPressed;

app_widget/lib/view/fade_in.dart

@@ -0,0 +1,148 @@
+import 'dart:async';
+
+import 'package:flutter/widgets.dart';
+
+class FadeIn extends StatefulWidget {
+  /// Fade-in controller
+  final FadeInController? controller;
+
+  /// Child widget to fade-in
+  final Widget? child;
+
+  /// Duration of fade-in. Defaults to 250ms
+  final Duration duration;
+
+  /// Fade-in curve. Defaults to [Curves.easeIn]
+  final Curve curve;
+
+  const FadeIn({
+    super.key,
+    this.controller,
+    this.child,
+    this.duration = const Duration(milliseconds: 250),
+    this.curve = Curves.easeIn,
+  });
+
+  @override
+  State<FadeIn> createState() => _FadeInState();
+}
+
+enum FadeInAction {
+  fadeIn,
+  fadeOut,
+}
+
+/// Fade-in controller which dispatches fade-in/fade-out actions
+class FadeInController {
+  final _streamController = StreamController<FadeInAction>();
+
+  /// Automatically starts the initial fade-in. Defaults to false
+  final bool autoStart;
+
+  FadeInController({this.autoStart = false});
+
+  void dispose() => _streamController.close();
+
+  /// Fades-in child
+  void fadeIn() => run(FadeInAction.fadeIn);
+
+  /// Fades-out child
+  void fadeOut() => run(FadeInAction.fadeOut);
+
+  /// Dispatches a [FadeInAction]
+  void run(FadeInAction action) => _streamController.add(action);
+
+  /// Stream of [FadeInAction]s dispatched by this controller
+  Stream<FadeInAction> get stream => _streamController.stream;
+}
+
+class _FadeInState extends State<FadeIn> with TickerProviderStateMixin {
+  late AnimationController _controller;
+  StreamSubscription<FadeInAction>? _listener;
+
+  @override
+  void initState() {
+    super.initState();
+
+    _controller = AnimationController(
+      vsync: this,
+      duration: widget.duration,
+    );
+
+    _setupCurve();
+
+    if (widget.controller?.autoStart != false) {
+      fadeIn();
+    }
+
+    _listen();
+  }
+
+  void _setupCurve() {
+    final curve = CurvedAnimation(parent: _controller, curve: widget.curve);
+
+    Tween(
+      begin: 0.0,
+      end: 1.0,
+    ).animate(curve);
+  }
+
+  void _listen() {
+    if (_listener != null) {
+      _listener!.cancel();
+      _listener = null;
+    }
+
+    if (widget.controller != null) {
+      _listener = widget.controller!.stream.listen(_onAction);
+    }
+  }
+
+  void _onAction(FadeInAction action) {
+    switch (action) {
+      case FadeInAction.fadeIn:
+        fadeIn();
+        break;
+      case FadeInAction.fadeOut:
+        fadeOut();
+        break;
+    }
+  }
+
+  @override
+  void didUpdateWidget(FadeIn oldWidget) {
+    if (oldWidget.controller != widget.controller) {
+      _listen();
+    }
+
+    if (oldWidget.duration != widget.duration) {
+      _controller.duration = widget.duration;
+    }
+
+    if (oldWidget.curve != widget.curve) {
+      _setupCurve();
+    }
+
+    super.didUpdateWidget(oldWidget);
+  }
+
+  @override
+  void dispose() {
+    _controller.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return FadeTransition(
+      opacity: _controller,
+      child: widget.child,
+    );
+  }
+
+  /// Fades-in child
+  void fadeIn() => _controller.forward();
+
+  /// Fades-out child
+  void fadeOut() => _controller.reverse();
+}