IOS 如何將UIAlertController 顯示在viewController.view.window 最上面

要將UIAlertController放置windows最上面,這現象目前並不常見,但既然開發上遇到了,我還是寫下步驟好了,其實也很簡單.



1.首先先創建一個windows:

@property (strong, nonatomic) UIWindow *alertWindow;

- (UIWindow *)alertWindow { if (!_alertWindow) { _alertWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds]; UIViewController *viewController = [[UIViewController alloc] init]; _alertWindow.rootViewController = viewController; } return _alertWindow;}

2.當我們要切換presentViewController至windows時,輸入如下:

[self.alertWindow makeKeyAndVisible];
[self.alertWindow.rootViewController presentViewController:alertController animated:YES completion:nil];

3.至於要如何切回來原本的windows呢？只要在要切換的地方,輸入以下程式就可以了:

AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;
[appDelegate.window makeKeyAndVisible];