从背景回来时困在UIImageView上

Question

我一直在寻找一种解决方案，即在输入背景时不捕获缓存中的屏幕截图。我发现我可以通过调用UIImageView中的AppDelegate来捕获我的屏幕而不是自定义图像。

- (void)applicationDidEnterBackground:(UIApplication *)application {

      UIImageView *imageView = [[UIImageView alloc] initWithFrame:self.window.bounds];

      imageView.tag = 101;    
      imageView.backgroundColor = [UIColor blackColor];

      [UIApplication.sharedApplication.keyWindow.subviews.lastObject addSubview:imageView];   
}

- (void)applicationWillEnterForeground:(UIApplication *)application {

UIImageView *imageView = (UIImageView *)[UIApplication.sharedApplication.keyWindow.subviews.lastObject viewWithTag:101];   
[imageView removeFromSuperview];
}  

我的应用程序在一段时间后注销用户，显示用户已注销并返回主视图的错误。但是现在当应用程序在后台注销时，它不会在返回应用时删除UIImageView。我该如何删除UIImageView？

Answer 1

用强大的指针握住你的imageView！

@property (strong, nonatomic) UIImageView *imageView;
//...
- (void)applicationDidEnterBackground:(UIApplication *)application {

      self.imageView = [[UIImageView alloc] initWithFrame:self.window.bounds];
      self.imageView.backgroundColor = [UIColor blackColor];

      [UIApplication.sharedApplication.keyWindow.subviews.lastObject addSubview:imageView];   
}

- (void)applicationWillEnterForeground:(UIApplication *)application {
    [self.imageView removeFromSuperview];
}