iOS 在显示另一个之前关闭 UIAlertView

Question

我有一个 Utils 类，它在触发某些通知时显示 UIAlertView。有没有办法在显示新的 UIAlertView 之前关闭任何打开的 UIAlertView？

当前我在应用程序进入后台使用时执行此操作

[self checkViews:application.windows];

在 applicationDidEnterBackground 上

- (void)checkViews:(NSArray *)subviews {
    Class AVClass = [UIAlertView class];
    Class ASClass = [UIActionSheet class];
    for (UIView * subview in subviews){
        if ([subview isKindOfClass:AVClass]){
            [(UIAlertView *)subview dismissWithClickedButtonIndex:[(UIAlertView *)subview cancelButtonIndex] animated:NO];
        } else if ([subview isKindOfClass:ASClass]){
            [(UIActionSheet *)subview dismissWithClickedButtonIndex:[(UIActionSheet *)subview cancelButtonIndex] animated:NO];
        } else {
            [self checkViews:subview.subviews];
        }
    }
}

这使得 applicationDidEnterBackground 变得容易，因为我可以使用 application.windows

我可以使用 AppDelegate 或类似的东西来获取所有 View ，遍历它们并关闭任何 UIAlertViews 吗？

Answer 1

for (UIWindow* window in [UIApplication sharedApplication].windows) {
  NSArray* subviews = window.subviews;
  if ([subviews count] > 0)
    if ([[subviews objectAtIndex:0] isKindOfClass:[UIAlertView class]])
      [(UIAlertView *)[subviews objectAtIndex:0] dismissWithClickedButtonIndex:[(UIAlertView *)[subviews objectAtIndex:0] cancelButtonIndex] animated:NO];
}