How to scroll page in flutter

问题:

My code for a page is like this. i need to scroll part below appbar.

@override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(... ),
      body: new Stack(
        children: <Widget>[
          new Container(
            decoration: BoxDecoration(
                image: DecorationImage(...),
          new Column(children: [
            new Container(...),
            new Container(...... ),
            new Padding(
              child: SizedBox(
                child: RaisedButton(..),
            ),
            new Divider(),
            new Column(
              children: <Widget>[
                new Container(
                  child: new Row(
                    children: <Widget>[
                      new Expanded(
                        child: new Text(  ),
                      ),
                      new IconButton(
                        icon: IconButton(..),
                        onPressed: () {
                          _changed(true, "type");
                        },
                      ),
                    ],
                  ),
                ),
                visibilityPropertyType
                    ? new Container(
                        margin: EdgeInsets.all(24.0),
                        child: new Column(
                          children: <Widget>[
                            new Row(
                              children: <Widget>[
                                new Expanded(... ),
                                new RaisedButton(..)
                              ],
                            ),
                            new Padding(
                              padding: const EdgeInsets.only(top: 10.0),
                              child: new Row(
                                mainAxisAlignment:
                                    MainAxisAlignment.spaceEvenly,
                                children: <Widget>[
                                  new Column(
                                    children: <Widget>[
                                      new Row(  
                                        children: <Widget>[.. ]),
                                      new Row(
                                        children: <Widget>[]),
                                      new Row(
                                        children: <Widget>[]),
                                      new Row(
                                        children: <Widget>[],
                                  ),
                                  new Column(
                                    children: <Widget>[
                                      new Row(
                                        children: <Widget>[],
                                      ),
                                    ],
                                  ),
                                ],
                              ),
                            ),
                          ],
                        ))
                    : new Container(),
              ],
            ),
            new Divider(
              color: Colors.white,
            )
          ])
        ],
      ),
    );
  }

I need to make body part scrollable. How can i implement that scroll. If there is any custom scroll method existing. i have tried Scrollable and SingleChildScrollView but does not meet up with my needs. When i used SinglechildScrollView it occurs an error BoxConstraints forces an infinite height. if i removed LayoutBuilder it causes A RenderFlex overflowed by 22 pixels on the bottom error

回答1:

Wrap your widget tree inside a SingleChildScrollView

 body: SingleChildScrollView(
child: Stack(
    children: <Widget>[
      new Container(
        decoration: BoxDecoration(
            image: DecorationImage(...),
      new Column(children: [
        new Container(...),
        new Container(...... ),
        new Padding(
          child: SizedBox(
            child: RaisedButton(..),
        ),
....
...
 ); // Single child scroll view

Remember, SingleChildScrollView can only have one direct widget (Just like ScrollView in Android)

回答2:

Thanks guys for help. From your suggestions i reached a solution like this.

new LayoutBuilder(
        builder:
            (BuildContext context, BoxConstraints viewportConstraints) {
          return SingleChildScrollView(
            child: ConstrainedBox(
              constraints:
                  BoxConstraints(minHeight: viewportConstraints.maxHeight),
              child: Column(children: [
             // remaining stuffs
              ]),
            ),
          );
        },
      )

回答3:

You can try CustomScrollView. Put your CustomScrollView inside Column Widget.

Just for example -

class App extends StatelessWidget {

 App({Key key}): super(key: key);

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: AppBar(
          title: const Text('AppBar'),
      ),
      body: new Container(
          constraints: BoxConstraints.expand(),
          decoration: new BoxDecoration(
            image: new DecorationImage(
              alignment: Alignment.topLeft,
              image: new AssetImage('images/main-bg.png'),
              fit: BoxFit.cover,
            )
          ),
          child: new Column(
            children: <Widget>[               
              Expanded(
                child: new CustomScrollView(
                  scrollDirection: Axis.vertical,
                  shrinkWrap: false,
                  slivers: <Widget>[
                    new SliverPadding(
                      padding: const EdgeInsets.symmetric(vertical: 0.0),
                      sliver: new SliverList(
                        delegate: new SliverChildBuilderDelegate(
                          (context, index) => new YourRowWidget(),
                          childCount: 5,
                        ),
                      ),
                    ),
                  ],
                ),
              ),
            ],
          )),
    );
  }
}

In above code I am displaying a list of items ( total 5) in CustomScrollView. YourRowWidget widget gets rendered 5 times as list item. Generally you should render each row based on some data.

You can remove decoration property of Container widget, it is just for providing background image.

回答4:

Two way to add Scroll in page

1. Using SingleChildScrollView :

     SingleChildScrollView(
          child: Column(
            children: [
              Container(....),
              SizedBox(...),
              Container(...),
              Text(....)
            ],
          ),
      ),

2. Using ListView : ListView is default provide Scroll no need to add extra widget for scrolling

     ListView(
          children: [
            Container(..),
            SizedBox(..),
            Container(...),
            Text(..)
          ],
      ),