Android 在颤振中绘制应用程序。被重新绘制卡住了

这是我的应用程序的主.dart文件：

import 'package:flutter/material.dart';

main() {
  runApp(
    new MaterialApp(
      title: 'Flutter Database Test',
      theme: ThemeData(
        textTheme: TextTheme(
          display1: TextStyle(fontSize: 24.0, color: Colors.white),
          display2: TextStyle(fontSize: 24.0, color: Colors.grey),
          display3: TextStyle(fontSize: 18.0, color: Colors.black),
        ),
      ),
      home: new MyHomePage(),
    ),
  );
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  List<Color> color = [
    Colors.white,
    Colors.black,
    Colors.pink,
    Colors.blue,
    Colors.red,
    Colors.yellow,
    Colors.orange,
    Colors.green,
    Colors.cyan,
    Colors.purple,
    Colors.brown,
    Colors.indigo,
    Colors.teal,
    Colors.grey,
  ];

  Color _pencolor = Colors.white;
  Color _canvasclr = Colors.black;
  bool ispen = true;
  Color bc = Colors.black54;
  List<Offset> points = List<Offset>();
  GlobalKey<ScaffoldState> _skey = GlobalKey<ScaffoldState>();
  int cchanged = change[1];

  static var change = [1, 2, 0];

  @override
  Widget build(BuildContext context) {
    MyPainter _painter = MyPainter(color: cchanged, canvasp: points, changed: color.indexOf(_pencolor));
    _painter.addListener(() {
      print('hello');
    });
    return new Scaffold(
      resizeToAvoidBottomPadding: true,
      key: _skey,
      appBar: AppBar(
        backgroundColor: bc,
        elevation: 0.0,
        title: Text(
          'Draw',
          style: Theme.of(context).textTheme.display1,
        ),
        centerTitle: true,
        actions: <Widget>[
          IconButton(
              icon: Icon(Icons.content_paste),
              onPressed: () {
                _skey.currentState.showSnackBar(SnackBar(
                    backgroundColor: Colors.transparent,
                    content: Center(
                        child: Text(
                      'Choose Canvas Color',
                      textScaleFactor: 0.7,
                      style: Theme.of(context).textTheme.display3,
                    ))));
                ispen = false;
              }),
          IconButton(
              icon: Icon(Icons.edit),
              onPressed: () {
                _skey.currentState.showSnackBar(SnackBar(
                  content: Center(
                      child:
                          Text('Choose Pen Color', textScaleFactor: 0.7, style: Theme.of(context).textTheme.display3)),
                  backgroundColor: Colors.transparent,
                ));
                ispen = true;
              })
        ],
      ),
      drawer: Drawer(
        child: ListView(
          children: <Widget>[
            ListTile(
              title: Text('Create Canvas'),
              leading: Icon(Icons.add),
              onTap: () {
                //TODO
              },
            ),
            ListTile(
              title: Text('Connect to Canvas'),
              leading: Icon(Icons.compare_arrows),
              onTap: () {
                //TODO
              },
            )
          ],
        ),
      ),
      body: Container(
        color: bc,
        child: Column(
          children: <Widget>[
            Expanded(
              child: Padding(
                padding: const EdgeInsets.only(left: 8.0, right: 8.0, top: 10.0),
                child: ClipRRect(
                  child: Container(
                    color: _canvasclr,
                    child: GestureDetector(
                      onPanStart: (DragStartDetails d) {
                        points.add(Offset(d.globalPosition.dx, d.globalPosition.dy - 100));
                        cchanged = change[2];
                        print('${d.globalPosition},$points');
                        setState(() {});
                      },
                      onPanUpdate: (DragUpdateDetails d) {
                        points.add(Offset(d.globalPosition.dx, d.globalPosition.dy - 100));
                        print('${d.globalPosition}');
                        cchanged = change[0];
                        setState(() {});
                      },
                      child: CustomPaint(
                        isComplex: true,
                        willChange: false,
                        child: Container(),
                        painter: _painter,
                      ),
                    ),
                  ),
                  borderRadius: BorderRadius.circular(25.0),
                ),
              ),
            ),
            Container(
              height: 75.0,
              child: ListView.builder(
                scrollDirection: Axis.horizontal,
                shrinkWrap: true,
                itemCount: color.length,
                itemBuilder: (BuildContext context, int index) {
                  return InkWell(
                    splashColor: Colors.white,
                    onTap: () {
                      ispen ? _pencolor = color[index] : _canvasclr = color[index];
                      setState(() {});
                    },
                    child: Padding(
                      padding: const EdgeInsets.all(12.0),
                      child: CircleAvatar(
                        backgroundColor: color[index],
                      ),
                    ),
                  );
                },
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class MyPainter extends CustomPainter {
  final int color;
  final List<Offset> canvasp;
  Paint p = Paint();
  List<Paint> _paint = [
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.white,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.black,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.pink,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.blue,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.red,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.yellow,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.orange,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.green,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.cyan,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.purple,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.brown,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.indigo,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.teal,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.grey,
  ];

  final int changed;

  MyPainter({
    this.color,
    this.canvasp,
    this.changed,
  });

  @override
  void paint(Canvas canvas, Size size) {
    print('painting .......     $canvasp');
    for (int i = 0; i < canvasp.length; i++) {
      canvas.drawCircle(canvasp[i], 10.0, _paint[color]);
    }
  }

  @override
  bool shouldRepaint(MyPainter oldDelegate) {
    return oldDelegate.canvasp.length != canvasp.length;
  }
}

导入“包装：颤振/材料.省道”；
main（）{
runApp(
新材料聚丙烯(
标题：“颤振数据库测试”，
主题：主题数据(
textTheme:textTheme(
display1:TextStyle（fontSize:24.0，颜色：Colors.white），
display2:TextStyle（fontSize:24.0，颜色：Colors.grey），
display3:TextStyle（fontSize:18.0，颜色：Colors.black），
),
),
主页：新建MyHomePage（），
),
);
}
类MyHomePage扩展StatefulWidget{
@凌驾
_MyHomePageState createState（）=>new_MyHomePageState（）；
}
类_MyHomePageState扩展状态{
列表颜色=[
颜色，白色，
颜色，黑色，
颜色，粉色，
颜色，蓝色，
颜色，红色，
颜色，黄色，
颜色，橙色，
颜色，绿色，
颜色。青色，
颜色，紫色，
颜色，棕色，
蓝色，靛蓝，
蓝绿色，
颜色，灰色，
];
颜色_pencolor=Colors.white；
颜色_canvasclr=Colors.black；
bool-ispen=true；
颜色bc=颜色。黑色54；
列表点=列表（）；
GlobalKey _skey=GlobalKey（）；
int cchanged=变更[1]；
静态var变化=[1,2,0]；
@凌驾
小部件构建（构建上下文）{
MyPainter\u painter=MyPainter（颜色：更改，画布：点，更改：color.indexOf（\u pencolor））；
_painter.addListener（）{
打印（“你好”）；
});
归还新脚手架(
resizeToAvoidBottomPadding:true，
钥匙：_skey，
appBar:appBar(
背景颜色：bc，
标高：0.0，
标题：正文(
“画”，
样式：Theme.of（context）.textTheme.display1，
),
标题：对，
行动：[
图标按钮(
图标：图标（图标、内容和粘贴），
已按下：（）{
_skey.currentState.showSnackBar（SnackBar(
背景颜色：颜色。透明，
内容：中心(
子：文本(
“选择画布颜色”，
textScaleFactor:0.7，
样式：Theme.of（context）.textTheme.display3，
))));
ispen=假；
}),
图标按钮(
图标：图标（Icons.edit），
已按下：（）{
_skey.currentState.showSnackBar（SnackBar(
内容：中心(
儿童：
Text（'Choose Pen Color'，textScaleFactor:0.7，style:Theme.of（context.textTheme.display3）），
背景颜色：颜色。透明，
));
ispen=真；
})
],
),
抽屉(
子：ListView(
儿童：[
列表砖(
标题：文本（“创建画布”），
前导：图标（Icons.add），
onTap:（）{
//待办事项
},
),
列表砖(
标题：文本（“连接到画布”），
前导：图标（图标。比较箭头），
onTap:（）{
//待办事项
},
)
],
),
),
主体：容器(
颜色：公元前，
子：列(
儿童：[
扩大(
孩子：填充(
填充：仅限常量边集（左：8.0，右：8.0，顶：10.0），
孩子：ClipRRect(
子：容器(
颜色：_canvasclr，
儿童：手势检测器(
onPanStart：（DragStartD）{
添加（偏移量（d.globalPosition.dx，d.globalPosition.dy-100））；
cchanged=变更[2]；
打印（“${d.globalPosition}，$points”）；
setState（（）{}）；
},
onPanUpdate：（DragUpdate详细信息d）{
添加（偏移量（d.globalPosition.dx，d.globalPosition.dy-100））；
打印（“${d.globalPosition}”）；
cchanged=变更[0]；
setState（（）{}）；
},
孩子：定制油漆(
是的，
willChange:错，
子级：容器（），
画家：画家，
),
),
),
边界半径：边界半径。圆形（25.0），
),
),
),
容器(
身高：75.0，
子项：ListView.builder(
滚动方向：轴水平，
收缩膜：对，
itemCount:color.length，
itemBuilder:（构建上下文，int索引）{
回墨槽(
颜色：颜色。白色，
onTap:（）{
ispen？_pencolor=color[index]：_canvasclr=color[index]；
setState（（）{}）；
},
孩子：填充(
填充：常数边集全部（12.0），
孩子：圆环星(
背景颜色：颜色[索引]，
),
),
);
},
),
),
],
),
),
);
}
}
类MyPainter扩展了CustomPainter{
最终int颜色；
最后名单拉票；
油漆p=油漆（）；
列表_油漆=[
油漆（）
..strokeCap=strokeCap.round
..strokeJoin=strokeJoin.round
..冲程宽度=2.0
…颜色=颜色。白色，
油漆（）
..strokeCap=strokeCap.round
..strokeJoin=strokeJoin.round
..冲程宽度=2.0
…颜色=颜色。黑色，
油漆（）
..strokeCap=strokeCap.round
..strokeJoin=strokeJoin.round
@override
bool shouldRepaint(MyPainter oldDelegate) {
  return oldDelegate.canvasp.length != canvasp.length;
}

import 'package:flutter/material.dart';

main() {
  runApp(
    new MaterialApp(
      title: 'Flutter Database Test',
      theme: ThemeData(
        textTheme: TextTheme(
          display1: TextStyle(fontSize: 24.0, color: Colors.white),
          display2: TextStyle(fontSize: 24.0, color: Colors.grey),
          display3: TextStyle(fontSize: 18.0, color: Colors.black),
        ),
      ),
      home: new MyHomePage(),
    ),
  );
}

class MyHomePage extends StatefulWidget {
  @override
  _MyHomePageState createState() => new _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  List<Color> color = [
    Colors.white,
    Colors.black,
    Colors.pink,
    Colors.blue,
    Colors.red,
    Colors.yellow,
    Colors.orange,
    Colors.green,
    Colors.cyan,
    Colors.purple,
    Colors.brown,
    Colors.indigo,
    Colors.teal,
    Colors.grey,
  ];

  Color _pencolor = Colors.white;
  Color _canvasclr = Colors.black;
  bool ispen = true;
  Color bc = Colors.black54;
  List<Offset> points = List<Offset>();
  GlobalKey<ScaffoldState> _skey = GlobalKey<ScaffoldState>();
  int cchanged = change[1];
  int _revision = 0;

  static var change = [1, 2, 0];

  @override
  Widget build(BuildContext context) {
    MyPainter _painter =
        MyPainter(color: color.indexOf(_pencolor), canvasp: points, changed: cchanged, revision: _revision);
    _painter.addListener(() {
      print('hello');
    });
    return new Scaffold(
      resizeToAvoidBottomPadding: true,
      key: _skey,
      appBar: AppBar(
        backgroundColor: bc,
        elevation: 0.0,
        title: Text(
          'Draw',
          style: Theme.of(context).textTheme.display1,
        ),
        centerTitle: true,
        actions: <Widget>[
          IconButton(
            icon: Icon(Icons.content_paste),
            onPressed: !ispen
                ? null
                : () {
                    _skey.currentState.showSnackBar(
                      SnackBar(
                        backgroundColor: Colors.transparent,
                        content: Center(
                          heightFactor: 1.0,
                          child: Text(
                            'Choose Canvas Color',
                            textScaleFactor: 0.7,
                            style: Theme.of(context).textTheme.display3,
                          ),
                        ),
                      ),
                    );
                    setState(() {
                      ispen = false;
                    });
                  },
          ),
          IconButton(
            icon: Icon(Icons.edit),
            onPressed: ispen
                ? null
                : () {
                    _skey.currentState.showSnackBar(
                      SnackBar(
                        content: Center(
                            heightFactor: 1.0,
                            child: Text('Choose Pen Color',
                                textScaleFactor: 0.7, style: Theme.of(context).textTheme.display3)),
                        backgroundColor: Colors.transparent,
                      ),
                    );
                    setState(() {
                      ispen = true;
                    });
                  },
          )
        ],
      ),
      drawer: Drawer(
        child: ListView(
          children: <Widget>[
            ListTile(
              title: Text('Create Canvas'),
              leading: Icon(Icons.add),
              onTap: () {
                //TODO
              },
            ),
            ListTile(
              title: Text('Connect to Canvas'),
              leading: Icon(Icons.compare_arrows),
              onTap: () {
                //TODO
              },
            )
          ],
        ),
      ),
      body: Container(
        color: bc,
        child: Column(
          children: <Widget>[
            Expanded(
              child: Padding(
                padding: const EdgeInsets.only(left: 8.0, right: 8.0, top: 10.0),
                child: ClipRRect(
                  child: Container(
                    color: _canvasclr,
                    child: GestureDetector(
                      onPanStart: (DragStartDetails d) {
                        setState(() {
                          points.add(Offset(d.globalPosition.dx, d.globalPosition.dy - 100));
                          cchanged = change[2];
                          _revision++;
                        });
                        print('${d.globalPosition},$points');
                      },
                      onPanUpdate: (DragUpdateDetails d) {
                        print('${d.globalPosition}');
                        setState(() {
                          points.add(Offset(d.globalPosition.dx, d.globalPosition.dy - 100));
                          cchanged = change[0];
                          _revision++;
                        });
                      },
                      child: CustomPaint(
                        isComplex: true,
                        willChange: false,
                        child: Container(),
                        painter: _painter,
                      ),
                    ),
                  ),
                  borderRadius: BorderRadius.circular(25.0),
                ),
              ),
            ),
            Container(
              height: 75.0,
              child: ListView.builder(
                scrollDirection: Axis.horizontal,
                shrinkWrap: true,
                itemCount: color.length,
                itemBuilder: (BuildContext context, int index) {
                  return InkWell(
                    splashColor: Colors.white,
                    onTap: () {
                      setState(() {
                        ispen ? (_pencolor = color[index]) : (_canvasclr = color[index]);
                      });
                    },
                    child: Padding(
                      padding: const EdgeInsets.all(12.0),
                      child: CircleAvatar(
                        backgroundColor: color[index],
                      ),
                    ),
                  );
                },
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class MyPainter extends CustomPainter {
  final int color;
  final List<Offset> canvasp;
  final int revision;
  Paint p = Paint();
  List<Paint> _paint = [
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.white,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.black,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.pink,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.blue,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.red,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.yellow,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.orange,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.green,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.cyan,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.purple,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.brown,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.indigo,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.teal,
    Paint()
      ..strokeCap = StrokeCap.round
      ..strokeJoin = StrokeJoin.round
      ..strokeWidth = 2.0
      ..color = Colors.grey,
  ];

  final int changed;

  MyPainter({this.color, this.canvasp, this.changed, this.revision});

  @override
  void paint(Canvas canvas, Size size) {
    print('painting .......     $canvasp');
    for (int i = 0; i < canvasp.length; i++) {
      canvas.drawCircle(canvasp[i], 10.0, _paint[color]);
    }
  }

  @override
  bool shouldRepaint(MyPainter oldDelegate) {
    return oldDelegate.revision != revision;
  }
}