Flutter main() runs twice

Question

When i was debugging why widgets are building again and again, and found this issue.

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    print('Inside build');
    return MaterialApp( home: Container(child: Text('Hello World')));
 }
}

Output: flutter: Inside build

flutter: Inside build

Can someone explain why it printed twice? is it really rebuilding the MyApp() twice?

Answer 1

Fluttermain()不会运行两次，但由于print()已放置在 内部Widget build，因此可能的情况是某些原因导致屏幕重建。常见原因是setState()已调用或更改了屏幕方向。