flutter设置铺满

1. container的fit

Container(
  width: MediaQuery.of(context).size.width, // 屏幕宽度
  height: MediaQuery.of(context).size.height, // 屏幕高度
  child: Image.asset(
    "assets/icons/bg.png",
     fit: BoxFit.cover,
  ),
)

2. Position的构造函数fill

Stack(
  children: [
    Positioned.fill(
      child: Image.asset(
         "assets/icons/bg.png",
         fit: BoxFit.cover,
      ),
    ),
  ],
)

3. ConstrainedBox 的 constraints

ConstrainedBox(
  constraints: BoxConstraints.expand(), // 自适应屏幕
  child: Image.asset(
    "assets/icons/bg.png",
     fit: BoxFit.cover,
  ),
)