Display and style text Text: StatelessWidgetRichText : LeafRenderObjectW...

Single-child layout widgets：{ContainerPaddingCenterAlignFittedBoxAspectR...

Basic Widgets: {ContainerRowColumnImageTextIconRaisedButtonScaffoldAppba...

对应关系：View - Widget 区别：StatefulWidget 有状态 StateStatelessWidget 无状态