feat: add resizeBegin && resizeEnd Functions

lib/resizable_widget.dart

@@ -1,5 +1,5 @@
 /// Provide [ResizableWidget].
 library resizable_widget;
 
-export 'src/resizable_widget.dart' show ResizableWidget, OnResizedFunc;
+export 'src/resizable_widget.dart' show ResizableWidget, OnResizeBeginFunc, OnResizedFunc, OnResizeEndFunc;
 export 'src/widget_size_info.dart' show WidgetSizeInfo;

lib/src/resizable_widget.dart

@@ -1,12 +1,14 @@
 import 'package:flutter/material.dart';
-import 'package:resizable_widget/src/resizable_widget_args_info.dart';
+import 'resizable_widget_args_info.dart';
 import 'resizable_widget_child_data.dart';
 import 'resizable_widget_controller.dart';
 import 'separator.dart';
 import 'widget_size_info.dart';
 
 /// The callback argument type of [ResizableWidget.onResized].
 typedef OnResizedFunc = void Function(List<WidgetSizeInfo> infoList);
+typedef OnResizeBeginFunc = void Function(int separatorIndex, DragDownDetails details);
+typedef OnResizeEndFunc = void Function(int separatorIndex, DragEndDetails details);
 
 /// Holds resizable widgets as children.
 /// Users can resize the internal widgets by dragging.
@@ -48,23 +50,27 @@ class ResizableWidget extends StatefulWidget {
   /// Note that [onResized] is called every frame when resizing [children].
   final OnResizedFunc? onResized;
 
+  final OnResizeBeginFunc? onResizeBegin;
+
+  final OnResizeEndFunc? onResizeEnd;
+
   /// Creates [ResizableWidget].
   ResizableWidget({
     Key? key,
     required this.children,
     this.percentages,
-    @Deprecated('Use [isHorizontalSeparator] instead')
-        this.isColumnChildren = false,
+    @Deprecated('Use [isHorizontalSeparator] instead') this.isColumnChildren = false,
     this.isHorizontalSeparator = false,
     this.isDisabledSmartHide = false,
     this.separatorSize = 4,
     this.separatorColor = Colors.white12,
     this.onResized,
+    this.onResizeBegin,
+    this.onResizeEnd,
   }) : super(key: key) {
     assert(children.isNotEmpty);
     assert(percentages == null || percentages!.length == children.length);
-    assert(percentages == null ||
-        percentages!.reduce((value, element) => value + element) == 1);
+    assert(percentages == null || percentages!.reduce((value, element) => value + element) == 1);
   }
 
   @override

lib/src/resizable_widget_args_info.dart

@@ -8,7 +8,9 @@ class ResizableWidgetArgsInfo {
   final bool isDisabledSmartHide;
   final double separatorSize;
   final Color separatorColor;
+  final OnResizeBeginFunc? onResizeBegin;
   final OnResizedFunc? onResized;
+  final OnResizeEndFunc? onResizeEnd;
 
   ResizableWidgetArgsInfo(ResizableWidget widget)
       : children = widget.children,
@@ -20,5 +22,7 @@ class ResizableWidgetArgsInfo {
         isDisabledSmartHide = widget.isDisabledSmartHide,
         separatorSize = widget.separatorSize,
         separatorColor = widget.separatorColor,
-        onResized = widget.onResized;
+        onResized = widget.onResized,
+        onResizeBegin = widget.onResizeBegin,
+        onResizeEnd = widget.onResizeEnd;
 }

lib/src/resizable_widget_controller.dart

@@ -11,8 +11,7 @@ class ResizableWidgetController {
   final ResizableWidgetModel _model;
   List<ResizableWidgetChildData> get children => _model.children;
 
-  ResizableWidgetController(ResizableWidgetArgsInfo info)
-      : _model = ResizableWidgetModel(info) {
+  ResizableWidgetController(ResizableWidgetArgsInfo info) : _model = ResizableWidgetModel(info) {
     _model.init(_separatorFactory);
   }
 
@@ -21,13 +20,25 @@ class ResizableWidgetController {
     _model.callOnResized();
   }
 
+  void resizeStart(int separatorIndex, DragDownDetails details) {
+    _model.resizeStart(separatorIndex, details);
+    eventStream.add(this);
+    _model.callResizedBegin(separatorIndex, details);
+  }
+
   void resize(int separatorIndex, Offset offset) {
     _model.resize(separatorIndex, offset);
 
     eventStream.add(this);
     _model.callOnResized();
   }
 
+  void resizeEnd(int separatorIndex, DragEndDetails details) {
+    _model.resizeEnd(separatorIndex, details);
+    eventStream.add(this);
+    _model.callResizedEnd(separatorIndex, details);
+  }
+
   void tryHideOrShow(int separatorIndex) {
     final result = _model.tryHideOrShow(separatorIndex);
 

lib/src/resizable_widget_model.dart

@@ -20,11 +20,9 @@ class ResizableWidgetModel {
   void init(SeparatorFactory separatorFactory) {
     final originalChildren = _info.children;
     final size = originalChildren.length;
-    final originalPercentages =
-        _info.percentages ?? List.filled(size, 1 / size);
+    final originalPercentages = _info.percentages ?? List.filled(size, 1 / size);
     for (var i = 0; i < size - 1; i++) {
-      children.add(ResizableWidgetChildData(
-          originalChildren[i], originalPercentages[i]));
+      children.add(ResizableWidgetChildData(originalChildren[i], originalPercentages[i]));
       children.add(ResizableWidgetChildData(
           separatorFactory.call(SeparatorArgsBasicInfo(
             2 * i + 1,
@@ -62,6 +60,10 @@ class ResizableWidgetModel {
     }
   }
 
+  void resizeStart(int separatorIndex, DragDownDetails details) {
+    _info.onResizeBegin?.call(separatorIndex, details);
+  }
+
   void resize(int separatorIndex, Offset offset) {
     final leftSize = _resizeImpl(separatorIndex - 1, offset);
     final rightSize = _resizeImpl(separatorIndex + 1, offset * (-1));
@@ -92,11 +94,21 @@ class ResizableWidgetModel {
     }
   }
 
+  void resizeEnd(int separatorIndex, DragEndDetails details) {
+    _info.onResizeEnd?.call(separatorIndex, details);
+  }
+
+  void callResizedBegin(int separatorIndex, DragDownDetails details) {
+    _info.onResizeBegin?.call(separatorIndex, details);
+  }
+
   void callOnResized() {
-    _info.onResized?.call(children
-        .where((x) => x.widget is! Separator)
-        .map((x) => WidgetSizeInfo(x.size!, x.percentage!))
-        .toList());
+    _info.onResized?.call(
+        children.where((x) => x.widget is! Separator).map((x) => WidgetSizeInfo(x.size!, x.percentage!)).toList());
+  }
+
+  void callResizedEnd(int separatorIndex, DragEndDetails details) {
+    _info.onResizeEnd?.call(separatorIndex, details);
   }
 
   bool tryHideOrShow(int separatorIndex) {

lib/src/separator.dart

@@ -39,7 +39,9 @@ class _SeparatorState extends State<Separator> {
             height: _info.isHorizontalSeparator ? _info.size : double.infinity,
           ),
         ),
+        onPanDown: (details) => _controller.onPanStart(details),
         onPanUpdate: (details) => _controller.onPanUpdate(details, context),
+        onPanEnd: (details) => _controller.onPanEnd(details),
         onDoubleTap: () => _controller.onDoubleTap(),
       );
 }

lib/src/separator_controller.dart

@@ -7,10 +7,18 @@ class SeparatorController {
 
   const SeparatorController(this._index, this._parentController);
 
+  void onPanStart(DragDownDetails details) {
+    _parentController.resizeStart(_index, details);
+  }
+
   void onPanUpdate(DragUpdateDetails details, BuildContext context) {
     _parentController.resize(_index, details.delta);
   }
 
+  void onPanEnd(DragEndDetails details) {
+    _parentController.resizeEnd(_index, details);
+  }
+
   void onDoubleTap() {
     _parentController.tryHideOrShow(_index);
   }