build method

@override Widget build(BuildContext context)

根据屏幕尺寸返回对应的Widget

Implementation

@override
Widget build(BuildContext context) {
  final Size size = MediaQuery.of(context).size;
  final double width = size.width;

  if (width >= 1100) {
    // 桌面端优先显示
    if (desktop != null) return desktop!;
    if (tablet != null) return tablet!;
    return mobile;
  }
  if (width >= 650) {
    // 平板端
    if (tablet != null) return tablet!;
    if (desktop != null) return desktop!;
    return mobile;
  }
  // 移动端
  return mobile;
}