Migrate to onStateChanged function

Author: gonuit

example/lib/indicators/check_mark_indicator.dart

@@ -17,7 +17,6 @@ class CheckMarkIndicator extends StatefulWidget {
 class _CheckMarkIndicatorState extends State<CheckMarkIndicator>
     with SingleTickerProviderStateMixin {
   static const _indicatorSize = 150.0;
-  final _helper = IndicatorStateHelper();
 
   /// Whether to render check mark instead of spinner
   bool _renderCompleteState = false;
@@ -31,6 +30,20 @@ class _CheckMarkIndicatorState extends State<CheckMarkIndicator>
       onRefresh: () => Future.delayed(const Duration(seconds: 2)),
       child: widget.child,
       completeStateDuration: const Duration(seconds: 2),
+      onStateChanged: (change) {
+        /// set [_renderCompleteState] to true when controller.state become completed
+        if (change.didChange(to: IndicatorState.complete)) {
+          setState(() {
+            _renderCompleteState = true;
+          });
+
+          /// set [_renderCompleteState] to false when controller.state become idle
+        } else if (change.didChange(to: IndicatorState.idle)) {
+          setState(() {
+            _renderCompleteState = false;
+          });
+        }
+      },
       builder: (
         BuildContext context,
         Widget child,
@@ -41,23 +54,13 @@ class _CheckMarkIndicatorState extends State<CheckMarkIndicator>
             AnimatedBuilder(
               animation: controller,
               builder: (BuildContext context, Widget? _) {
-                _helper.update(controller.state);
-
                 if (controller.scrollingDirection == ScrollDirection.reverse &&
                     prevScrollDirection == ScrollDirection.forward) {
                   controller.stopDrag();
                 }
 
                 prevScrollDirection = controller.scrollingDirection;
 
-                /// set [_renderCompleteState] to true when controller.state become completed
-                if (_helper.didStateChange(to: IndicatorState.complete)) {
-                  _renderCompleteState = true;
-
-                  /// set [_renderCompleteState] to false when controller.state become idle
-                } else if (_helper.didStateChange(to: IndicatorState.idle)) {
-                  _renderCompleteState = false;
-                }
                 final containerHeight = controller.value * _indicatorSize;
 
                 return Container(

example/lib/indicators/warp_indicator.dart

@@ -15,11 +15,17 @@ typedef StarColorGetter = Color Function(int index);
 class WarpIndicator extends StatefulWidget {
   final Widget child;
   final int starsCount;
+  final OnRefresh onRefresh;
+  final IndicatorController? controller;
   final Color skyColor;
   final StarColorGetter starColorGetter;
+  final Key? indicatorKey;
 
   const WarpIndicator({
     Key? key,
+    this.indicatorKey,
+    this.controller,
+    required this.onRefresh,
     required this.child,
     this.starsCount = 30,
     this.skyColor = Colors.black,
@@ -37,7 +43,6 @@ class _WarpIndicatorState extends State<WarpIndicator>
     with SingleTickerProviderStateMixin {
   static const _indicatorSize = 150.0;
   final _random = Random();
-  final _helper = IndicatorStateHelper();
   WarpAnimationState _state = WarpAnimationState.stopped;
 
   List<Star> stars = [];
@@ -112,10 +117,19 @@ class _WarpIndicatorState extends State<WarpIndicator>
   @override
   Widget build(BuildContext context) {
     return CustomRefreshIndicator(
+      key: widget.indicatorKey,
+      controller: widget.controller,
       offsetToArmed: _indicatorSize,
       leadingGlowVisible: false,
       trailingGlowVisible: false,
-      onRefresh: () => Future.delayed(const Duration(seconds: 2)),
+      onRefresh: widget.onRefresh,
+      onStateChanged: (change) {
+        if (change.didChange(to: IndicatorState.loading)) {
+          _startShakeAnimation();
+        } else if (change.didChange(to: IndicatorState.idle)) {
+          _stopShakeAnimation();
+        }
+      },
       child: widget.child,
       builder: (
         BuildContext context,
@@ -144,18 +158,6 @@ class _WarpIndicatorState extends State<WarpIndicator>
             AnimatedBuilder(
               animation: animation,
               builder: (context, _) {
-                _helper.update(controller.state);
-                if (_helper.didStateChange(
-                  to: IndicatorState.loading,
-                )) {
-                  SchedulerBinding.instance
-                      ?.addPostFrameCallback((_) => _startShakeAnimation());
-                } else if (_helper.didStateChange(
-                  to: IndicatorState.idle,
-                )) {
-                  SchedulerBinding.instance
-                      ?.addPostFrameCallback((_) => _stopShakeAnimation());
-                }
                 return Transform.scale(
                   scale: _scaleTween.transform(controller.value),
                   child: Builder(builder: (context) {

example/lib/screens/warp_indicator_screen.dart

@@ -17,6 +17,7 @@ class _WarpIndicatorScreenState extends State<WarpIndicatorScreen> {
       appBar: const ExampleAppBar(),
       body: SafeArea(
         child: WarpIndicator(
+          onRefresh: () => Future.delayed(const Duration(seconds: 2)),
           child: const ExampleList(),
         ),
       ),

lib/custom_refresh_indicator.dart

@@ -1,5 +1,6 @@
 library custom_refresh_indicator;
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
@@ -8,3 +9,4 @@ part 'src/helpers/positioned_indicator_container.dart';
 part 'src/custom_refresh_indicator.dart';
 part 'src/controller.dart';
 part 'src/helpers/indicator_state_helper.dart';
+part 'src/helpers/indicator_state_change.dart';

lib/src/helpers/indicator_state_change.dart

@@ -0,0 +1,26 @@
+part of custom_refresh_indicator;
+
+/// Describes [IndicatorState] change.
+@immutable
+class IndicatorStateChange {
+  final IndicatorState currentState;
+  final IndicatorState newState;
+
+  const IndicatorStateChange(this.currentState, this.newState);
+
+  /// - When [from] and [to] are provided - returns `true` when state did change [from] to [to].
+  /// - When only [from] is provided - returns `true` when state did change from [from].
+  /// - When only [to] is provided - returns `true` when state did change to [to].
+  /// - When [from] and [to] equals `null` - returns `true` for any state change.
+  bool didChange({IndicatorState? from, IndicatorState? to}) {
+    final stateChanged = currentState != newState;
+    if (to == null && from != null) return currentState == from && stateChanged;
+    if (to != null && from == null) return newState == to && stateChanged;
+    if (to == null && from == null) return stateChanged;
+    return currentState == from && newState == to;
+  }
+
+  @override
+  String toString() =>
+      "$runtimeType(${describeEnum(currentState)} → ${describeEnum(newState)})";
+}

lib/src/helpers/indicator_state_helper.dart

@@ -59,28 +59,3 @@ class IndicatorStateHelper {
     return _previousState == from && _currentState == to;
   }
 }
-
-/// Describes [IndicatorState] change.
-@immutable
-class IndicatorStateChange {
-  final IndicatorState currentState;
-  final IndicatorState newState;
-
-  const IndicatorStateChange(this.currentState, this.newState);
-
-  /// - When [from] and [to] are provided - returns `true` when state did change [from] to [to].
-  /// - When only [from] is provided - returns `true` when state did change from [from].
-  /// - When only [to] is provided - returns `true` when state did change to [to].
-  /// - When [from] and [to] equals `null` - returns `true` for any state change.
-  bool didChange({IndicatorState? from, IndicatorState? to}) {
-    final stateChanged = currentState != newState;
-    if (to == null && from != null) return currentState == from && stateChanged;
-    if (to != null && from == null) return newState == to && stateChanged;
-    if (to == null && from == null) return stateChanged;
-    return currentState == from && newState == to;
-  }
-
-  @override
-  String toString() =>
-      "$runtimeType(${describeEnum(currentState)} → ${describeEnum(newState)})";
-}