The Expanded component allows Row, Column, Flex and other sub-components to expand in the direction of their main axis and fill the available space. Similar usage of widget properties in Android
Expanded will be distributed as full as possible in the main axis direction of Row, Column, or Flex
If Column contains two childs and two widgets are expanded, both share the
available vertical space evenly.
If only one is expanded, the expanded one takes up
all the available vertical space.
If neither is expanded, the available vertical space
goes unfilled
Example:
|
class ExpandedWidget extends StatelessWidget { @override Widget build(BuildContext context) { // TODO: implement build return MaterialApp( home: Scaffold( appBar: AppBar(backgroundColor: Colors.pink,title: Text("Expanded Widget"),), body: new Row( children: <Widget>[ new Expanded( flex: 2, child: new Container( child: new Text('Text1', textAlign: TextAlign.center), height: 100, alignment: AlignmentDirectional.center, color: Colors.yellow, ), ), new Expanded( flex: 1, child: new Container( child: new Text('Text2', textAlign: TextAlign.center), height: 100, alignment: AlignmentDirectional.center, color: Colors.lightGreen, ), ), new Expanded( flex: 1, child: new Container( child: new Text('Text3', textAlign: TextAlign.center), height: 100, alignment: AlignmentDirectional.center, color: Colors.deepPurple, ), ), ], ), )); } } |
It is actually Expanded inheritance Flexible. Use Flexible widgets to Row, Column or Flex provided in the main shaft expands to fill the available space in flexibility (e.g., horizontal filling sub assembly Row or perpendicular filled Column), but Expandeddifferent, Flexible is not required to fill the available space sub components.
Flexible The control must be Row, Column or Flex a descendant of Row, the path from the control to its closure , Column or Flex the path must contain only Stateless Widgets or Stateful Widget these, and cannot be other types of widgets (for example Render ObjectWidget)
This widget is used to center a Widget within its parent
Widget.
