添加了PaintEvent

CHANGELOG.md

-## [0.0.1] - TODO: Add release date.
+## [0.1.0] - TODO: 改进了CupertionPopover和添加了CupertinoPopoverMenuItem
 
-* TODO: Describe initial release.
+* TODO: 改进了CupertionPopover箭头的位置
+* TODO: 改进了CupertinoPopoverMenuItem按下的动画，并且添加了onTap
 
 ## [0.0.9] - TODO: 添加了一些控件,改进了CupertionPopover
 
@@ -8,7 +9,7 @@
 * TODO: 添加了CupertinoPopoverMenuItem
 * TODO: 修改了CupertionPopover动画,
 
-## [0.1.0] - TODO: 改进了CupertionPopover和添加了CupertinoPopoverMenuItem
+## [0.0.1] - TODO: Add release date.
+
+* TODO: Describe initial release.
 
-* TODO: 改进了CupertionPopover箭头的位置
-* TODO: 改进了CupertinoPopoverMenuItem按下的动画，并且添加了onTap
\ No newline at end of file

example/lib/main.dart

 import 'package:cool_ui_example/cool_u_i_example_icons.dart';
+import 'package:cool_ui_example/pages/PaintEventDemo.dart';
 import 'package:cool_ui_example/pages/PopoverDemo.dart';
 import 'package:flutter/material.dart';
 
@@ -80,6 +81,12 @@ class _MyHomePageState extends State<MyHomePage> {
             onTap: (){
               Navigator.of(context).push(MaterialPageRoute(builder: (context)=>PopoverDemo()));
             },
+          ),
+          ListTile(
+            title: Text("PaintEvent"),
+            onTap: (){
+              Navigator.of(context).push(MaterialPageRoute(builder: (context)=>PaintEventDemo()));
+            },
           )
         ],
       )

example/lib/pages/PaintEventDemo.dart

+import 'package:flutter/material.dart';
+import 'package:flutter/cupertino.dart';
+import 'package:cool_ui/cool_ui.dart';
+
+
+class PaintEventDemo extends StatefulWidget{
+  @override
+  State<StatefulWidget> createState() {
+    // TODO: implement createState
+    return PaintEventDemoState();
+  }
+
+}
+
+class PaintEventDemoState extends State<PaintEventDemo>{
+  bool isPaintBackgroud = false;
+
+
+  @override
+  Widget build(BuildContext context) {
+    // TODO: implement build
+    return Scaffold(
+        appBar: AppBar(
+          title: Text("Popover Demo"),
+        ),
+        body: Row(
+          children: <Widget>[
+            FlatButton(onPressed: (){
+              setState((){
+                isPaintBackgroud = !isPaintBackgroud;
+              });
+            }, child: Text(isPaintBackgroud?"渲染前填充颜色":"渲染后填充颜色")),
+            PaintEvent(
+              child: Text("子Widget文字"),
+              paintAfter: (context,offset,size){
+                if(!isPaintBackgroud){
+                  final Paint paint = Paint();
+                  paint.color = Colors.red;
+                  context.canvas.drawRect(offset&size, paint);
+                }
+              },paintBefore: (context,offset,size){
+              if(isPaintBackgroud){
+                final Paint paint = Paint();
+                paint.color = Colors.red;
+                context.canvas.drawRect(offset&size, paint);
+              }
+            },
+            )
+          ],
+        )
+    );
+  }
+
+  Widget _buildPopoverButton(String btnTitle,String bodyMessage){
+    return Padding(
+        padding:  EdgeInsets.all(20.0),
+        child:CupertinoPopoverButton(
+
+            child: Container(
+              width: 80.0,
+              height: 40.0,
+              decoration: BoxDecoration(
+                  color: Colors.white,
+                  borderRadius: BorderRadius.all(Radius.circular(5.0)),
+                  boxShadow: [BoxShadow(color: Colors.black12,blurRadius: 5.0)]
+              ),
+              child: Center(child:Text(btnTitle)),
+            ),
+            popoverBuild: (context) {
+              return CupertinoPopoverMenuList(
+                children: <Widget>[
+                  CupertinoPopoverMenuItem(leading: Icon(Icons.add),child: Text("新增"),),
+                  CupertinoPopoverMenuItem(leading: Icon(Icons.edit),child: Text("修改"),),
+                  CupertinoPopoverMenuItem(leading: Icon(Icons.delete),child: Text("删除"),)
+                ],
+              );
+            },
+            popoverWidth: 150.0,
+            popoverHeight: 123.0)
+
+    );
+
+  }
+}
\ No newline at end of file

example/lib/pages/PopoverDemo.dart

@@ -52,6 +52,7 @@ class PopoverDemoState extends State<PopoverDemo>{
     return Padding(
         padding:  EdgeInsets.all(20.0),
         child:CupertinoPopoverButton(
+
             child: Container(
               width: 80.0,
               height: 40.0,
@@ -73,6 +74,8 @@ class PopoverDemoState extends State<PopoverDemo>{
             },
             popoverWidth: 150.0,
             popoverHeight: 123.0)
+
     );
+
   }
 }
\ No newline at end of file

lib/cool_ui.dart

 library cool_ui;
 import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
 
 part 'utils/screen_utils.dart';
 part 'utils/widget_utils.dart';
 
 part 'widgets/popover/cupertino_popover.dart';
 part 'widgets/popover/cupertino_popover_menu_item.dart';
+
+part 'widgets/utils/paint_event.dart';

lib/widgets/utils/paint_event.dart

+part of cool_ui;
+
+typedef PaintCallback = void Function(PaintingContext context, Offset offset,Size size);
+
+class PaintEvent extends SingleChildRenderObjectWidget{
+
+
+  final PaintCallback paintBefore;
+  final PaintCallback paintAfter;
+
+
+  const PaintEvent({
+    Key key,
+    this.paintBefore,
+    this.paintAfter,
+    Widget child
+  }) :
+        super(key: key, child: child);
+  @override
+  PaintEventProxyBox createRenderObject(BuildContext context) {
+    return PaintEventProxyBox(
+      paintAfter: paintAfter,
+      paintBefore: paintBefore
+    );
+  }
+
+  @override
+  void updateRenderObject(BuildContext context, PaintEventProxyBox renderObject) {
+    renderObject..paintAfter = paintBefore
+          ..paintAfter = paintAfter;
+  }
+
+}
+
+
+class PaintEventProxyBox extends RenderProxyBox{
+  PaintCallback paintBefore;
+  PaintCallback paintAfter;
+
+  PaintEventProxyBox({
+    RenderBox child,
+    this.paintBefore,
+    this.paintAfter
+  }):super(child);
+
+  @override
+  void detach() {
+    super.detach();
+    markNeedsPaint();
+  }
+
+  @override
+  void paint(PaintingContext context, Offset offset) {
+    assert(size.width != null);
+    assert(size.height != null);
+
+    if(this.paintBefore != null){
+      this.paintBefore(context,offset,size);
+    }
+
+    super.paint(context, offset);
+
+
+
+    if(this.paintAfter != null){
+      this.paintAfter(context,offset,size);
+    }
+
+  }
+}
\ No newline at end of file