Container 组件
padding: const EdgeInsets.fromLTRB(10, 0, 30, 0),//外边距
margin: const EdgeInsets.all(10),// 内边距
decoration: new BoxDecoration(
gradient: const LinearGradient(
colors: [
Colors.lightBlue,
Colors.greenAccent,
Colors.purple
]
)
),//渐变