flutter row 里面的元素分别居左和居右对齐

1.new Row(

  mainAxisAlignment: MainAxisAlignment.spaceBetween,

  children: [

    new Text("left"),

    new Text("right")

  ]

);

2.Row(

  children: <Widget>[

    FlutterLogo(),//左对齐

    Expanded(child: SizedBox()),//自动扩展挤压

    FlutterLogo(),//右对齐

  ],

);

3.Row(

  children: <Widget>[

    FlutterLogo(),

    Spacer(),

    FlutterLogo(),

  ],

);

4.Row(

  children: <Widget>[

    FlutterLogo(),

    Flexible(fit: FlexFit.tight, child: SizedBox()),

    FlutterLogo(),

  ],

);