【问题标题】:A RenderFlex overflowed by 729 pixels on the bottom. in SingleChildScrollView一个 RenderFlex 在底部溢出了 729 个像素。在 SingleChildScrollView
【发布时间】:2020-02-18 02:12:58
【问题描述】:

一个 RenderFlex 在底部溢出了 676 像素。在 SingleChildScrollView 中

小部件仪表板(上下文){ 返回动画定位( 持续时间:持续时间, 顶部:0, 底部:0, 左:是折叠? 0 : 0.6 * 屏幕宽度, 对:isCollapsed 吗? 0 : -0.2 * 屏幕宽度, 孩子:ScaleTransition( 规模:_scaleAnimation, 孩子:材料( 动画持续时间:持续时间, 边界半径:边界半径.all( 半径.圆形(40), ), 海拔:8, 颜色:背景颜色, 孩子:列( crossAxisAlignment:CrossAxisAlignment.start, 孩子们: [ 容器( 填充:const EdgeInsets.only(左:16,右:16,上:48), 孩子:行( mainAxisAlignment: MainAxisAlignment.spaceBetween, mainAxisSize: MainAxisSize.max, 孩子们:[ 墨水井( 孩子:图标( 图标.菜单, 颜色:颜色.白色 ), 点按:(){ 设置状态((){ 如果(已折叠) _controller.forward(); 别的 _controller.reverse();

                        isCollapsed = !isCollapsed;
                      });
                    },
                  ),
                  Text(
                    " Técnico",
                    style: TextStyle(
                      fontSize: 24,
                      color: Colors.white,
                    ),
                  ),
                  Icon(
                    Icons.settings,
                    color: Colors.white,
                  ),
                ]),
          ),
          Container(
              child: SingleChildScrollView(
                scrollDirection: Axis.vertical,
                physics: ClampingScrollPhysics(),
                child: Column(
                  children: <Widget>[
                  SizedBox(
                    height: 5,
                  ),
                  SizedBox(
                    height:20 ,
                  ),
                  Text("Chamados",
                  style: TextStyle(
                    color: Colors.white,
                    fontSize: 20,
                  ) ,
                  ),
                  SizedBox(
                    height:5 ,
                  ),
                  ListView.separated(
                      shrinkWrap: true,
                      itemBuilder: (context,index){
                    return ListTile(
                      title: Text("Falta de Sinal"),
                      subtitle: Text("João"),
                      trailing: Text("20mb"),
                    );
                  }, separatorBuilder: (context,index){
                    return Divider(
                      height: 16,
                    );
                  }, itemCount: 16),
                ],
                ),
              ),
          ),
      ],
      ),
    ),
  ),
);

}

【问题讨论】:

标签: flutter dart


【解决方案1】:
  1. 如果您在列或行内使用SingleChildScrollView,则使用Expanded Widget 包装。

    e.g. Column(
         childreen[
            Expanded(
                child : SingleChildScrollView(
                     // your code ...
              ),                  
           ]),
    
  2. 或者您可以为容器提供高度。

      e.g. -> Container(
                  height : 300.0,
                  child : SingleChildScrollView(
                    // your code ...              
                     ),
                  ),
    

编码愉快... :)

【讨论】:

    【解决方案2】:

    用Container包裹ListView.separated并添加约束,设置maxHeight有效,如下图

    代码sn-p

    Container(
                  constraints: BoxConstraints(
                    maxHeight: 300.0,
                  ),
                  child: ListView.separated(
                      shrinkWrap: true,
                      itemBuilder: (context, index) {
                        return ListTile(
                          title: Text("Falta de Sinal"),
                          subtitle: Text("João"),
                          trailing: Text("20mb"),
                        );
                      },
                      separatorBuilder: (context, index) {
                        return Divider(
                          height: 16,
                        );
                      },
                      itemCount: 16),
                ),
    

    完整的测试代码

        import 'package:flutter/material.dart';
    
    void main() => runApp(MyApp());
    
    class MyApp extends StatelessWidget {
      // This widget is the root of your application.
      @override
      Widget build(BuildContext context) {
        return MaterialApp(
          title: 'Flutter Demo',
          theme: ThemeData(
            // This is the theme of your application.
            //
            // Try running your application with "flutter run". You'll see the
            // application has a blue toolbar. Then, without quitting the app, try
            // changing the primarySwatch below to Colors.green and then invoke
            // "hot reload" (press "r" in the console where you ran "flutter run",
            // or simply save your changes to "hot reload" in a Flutter IDE).
            // Notice that the counter didn't reset back to zero; the application
            // is not restarted.
            primarySwatch: Colors.blue,
          ),
          home: MyHomePage(title: 'Flutter Demo Home Page'),
        );
      }
    }
    
    class MyHomePage extends StatefulWidget {
      MyHomePage({Key key, this.title}) : super(key: key);
    
      // This widget is the home page of your application. It is stateful, meaning
      // that it has a State object (defined below) that contains fields that affect
      // how it looks.
    
      // This class is the configuration for the state. It holds the values (in this
      // case the title) provided by the parent (in this case the App widget) and
      // used by the build method of the State. Fields in a Widget subclass are
      // always marked "final".
    
      final String title;
    
      @override
      _MyHomePageState createState() => _MyHomePageState();
    }
    
    class _MyHomePageState extends State<MyHomePage> {
      int _counter = 0;
    
      void _incrementCounter() {
        setState(() {
          // This call to setState tells the Flutter framework that something has
          // changed in this State, which causes it to rerun the build method below
          // so that the display can reflect the updated values. If we changed
          // _counter without calling setState(), then the build method would not be
          // called again, and so nothing would appear to happen.
          _counter++;
        });
      }
    
      @override
      Widget build(BuildContext context) {
        // This method is rerun every time setState is called, for instance as done
        // by the _incrementCounter method above.
        //
        // The Flutter framework has been optimized to make rerunning build methods
        // fast, so that you can just rebuild anything that needs updating rather
        // than having to individually change instances of widgets.
        return Scaffold(
          appBar: AppBar(
            // Here we take the value from the MyHomePage object that was created by
            // the App.build method, and use it to set our appbar title.
            title: Text(widget.title),
          ),
          body: Center(
            // Center is a layout widget. It takes a single child and positions it
            // in the middle of the parent.
            child: Column(
              // Column is also a layout widget. It takes a list of children and
              // arranges them vertically. By default, it sizes itself to fit its
              // children horizontally, and tries to be as tall as its parent.
              //
              // Invoke "debug painting" (press "p" in the console, choose the
              // "Toggle Debug Paint" action from the Flutter Inspector in Android
              // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
              // to see the wireframe for each widget.
              //
              // Column has various properties to control how it sizes itself and
              // how it positions its children. Here we use mainAxisAlignment to
              // center the children vertically; the main axis here is the vertical
              // axis because Columns are vertical (the cross axis would be
              // horizontal).
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                dashboard(context),
                Text(
                  'You have pushed the button this many times:',
                ),
                Text(
                  '$_counter',
                  style: Theme.of(context).textTheme.display1,
                ),
              ],
            ),
          ),
          floatingActionButton: FloatingActionButton(
            onPressed: _incrementCounter,
            tooltip: 'Increment',
            child: Icon(Icons.add),
          ), // This trailing comma makes auto-formatting nicer for build methods.
        );
      }
    
      Widget dashboard(context) {
        return Container(
          child: SingleChildScrollView(
            scrollDirection: Axis.vertical,
            physics: ClampingScrollPhysics(),
            child: Column(
              children: <Widget>[
                SizedBox(
                  height: 5,
                ),
                SizedBox(
                  height: 20,
                ),
                Text(
                  "Chamados",
                  style: TextStyle(
                    color: Colors.black,
                    fontSize: 20,
                  ),
                ),
                SizedBox(
                  height: 5,
                ),
                Container(
                  constraints: BoxConstraints(
                    maxHeight: 300.0,
                  ),
                  child: ListView.separated(
                      shrinkWrap: true,
                      itemBuilder: (context, index) {
                        return ListTile(
                          title: Text("Falta de Sinal"),
                          subtitle: Text("João"),
                          trailing: Text("20mb"),
                        );
                      },
                      separatorBuilder: (context, index) {
                        return Divider(
                          height: 16,
                        );
                      },
                      itemCount: 16),
                ),
              ],
            ),
          ),
        );
      }
    }
    

    【讨论】:

    【解决方案3】:

    添加高度是一个不错的选择,但你应该使用 Expanded inside 列

    【讨论】:

      【解决方案4】:

      我正在回答它,因为没有人提到我们为什么会得到这个,

      所以,这通常是因为内容对于 RenderFlex 来说太大了。 通过应用 flex 因子(例如,使用 Expanded 小部件或 Flexibel,它也是 Expanded 小部件的一种)来强制 Widget 的子级 RenderFlex 适应可用空间,而不是调整到它们的自然大小。 你甚至可以访问这个以获得更清晰的信息 Flutter (Dart): Exceptions caused by rendering / A RenderFlex overflowed。还有这个https://docs.flutter.dev/testing/common-errors,希望对你有帮助。

      【讨论】:

        【解决方案5】:

        在您的专栏中使用 mainAxisSize,将防止该问题 柱子( mainAxisSize: MainAxisSize.min, 孩子们: [ ) ], ),

        【讨论】:

          【解决方案6】:

          Column( mainAxisSize: MainAxisSize.min, children: &lt;Widget&gt;[ Text( filename, style: TextStyle( color: dsecondaryColor, fontWeight: FontWeight.bold), ) ], ),

          【讨论】:

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