當我appbar抽出來的時候。如：
class getAppBarWidget extends StatelessWidget {
@override
Widget build(BuildContext context) {
// TODO: implement build
return new AppBar(
title: new Text(this.name),
);
}
final String name;
getAppBarWidget({Key key, @required this.name}) :super(key: key);
}
引用的時候會出現問題
'getAppBarWidget' can't be assigned to the parameter type 'PreferredSizeWidget'.
解決方法
class getAppBarWidget extends StatelessWidget implements PreferredSizeWidget {
@override
Widget build(BuildContext context) {
// TODO: implement build
return new AppBar(
title: new Text(this.name),
);
}
final String name;
getAppBarWidget({Key key, @required this.name}) :super(key: key);
@override
// TODO: implement preferredSize
Size get preferredSize => getSize();
Size getSize() {
return new Size(100.0, 100.0);
}
}
Scaffold需要appbar作為實現PreferredSizeWidget的類
