安卓一般View有三种显示方式gone visible invisible
fultter也要提供相应的支持，这个是验证可用的
import 'package:flutter/widgets.dart';
import 'package:meta/meta.dart';
enum VisibilityFlag {
visible,
invisible,
offscreen,
gone,
}
class Visibility extends StatelessWidget {
final VisibilityFlag visibility;
final Widget child;
final Widget removeChild;
Visibility({
@required this.child,
@required this.visibility,
}) : this.removeChild = Container();
@override
Widget build(BuildContext context) {
if (visibility == VisibilityFlag.visible) {
return child;
} else if (visibility == VisibilityFlag.invisible) {
return new IgnorePointer(
ignoring: true, child: new Opacity(opacity: 0.0, child: child));
} else if (visibility == VisibilityFlag.offscreen) {
return new Offstage(offstage: true, child: child);
} else {
return removeChild;
}
}
}
