let the FLBViewController re-layout when it will be appear

example/ios/Runner/NativeViewController.m

@@ -48,7 +48,7 @@
 - (void)viewDidAppear:(BOOL)animated{
     [super viewDidAppear:animated];
     //注意这行代码不可缺少
-    [self.flutterContainer.view setNeedsLayout];
+//    [self.flutterContainer.view setNeedsLayout];
 //    [self.flutterContainer.view layoutIfNeeded];
 }
 /*

ios/Classes/container/FLBFlutterViewContainer.m

@@ -183,6 +183,7 @@ static NSUInteger kInstanceCounter = 0;
     }
  
     [super viewWillAppear:animated];
+    [self.view setNeedsLayout];
     //instead of calling [super viewWillAppear:animated];, call super's super
 //    struct objc_super target = {
 //        .super_class = class_getSuperclass([FlutterViewController class]),