如何知道是否有UIActionSheet顯示在視圖層次結構中？

Question

如何知道View Hierarchy中是否有UIActionSheet？ 另外我想獲得一個參考UIActionSheet，有什麼好主意？

Answer 1

請注意，在iOS6上，您需要遞歸搜索來查找UIActionSheet，它現在不是UIWindow的直接子視圖。

static UIView *actionSheet = nil; 
-(void)findActionSheetInSubviewsOfView:(id)view 
{ 
    if (actionSheet) { 
     return; 
    } 
    if ([[view valueForKey:@"subviews"] count] != 0) { 
     for (id subview in [view valueForKey:@"subviews"]) { 
      if ([subview isKindOfClass:[UIActionSheet class]]) { 
       actionSheet = subview; 
      } 
      else 
       [self findActionSheetInSubviewsOfView:subview]; 
     } 
    } 
} 

-(UIActionSheet*) actionSheetShowing { 
    actionSheet = nil; 
    for (UIWindow* window in [UIApplication sharedApplication].windows) { 
     [self findActionSheetInSubviewsOfView:window]; 
    } 

    if (actionSheet) { 
     return (UIActionSheet*)actionSheet; 
    } 
    return nil; 
}