UIAlertController显示空白标题的UIAlertActions

Question

最近，我终于重构了一个传统项目，并已将所有UIAlertViews和UIActionSheets转换为UIAlertControllers。但我已经开始接受客户的问题，他们说有时UIAlertController操作标题是空白的。像这样：

我不能重现这个bug在我的设备，你有没有对可能的原因，任何想法？

UPDATE：

我相信，这个问题被覆盖的代码，也许主窗口莫名其妙不是默认的tintColor，并UIAlertController继承呢？

@implementation UIAlertController (WMC) 

    - (void)show:(BOOL)animated { 
     self.alertWindow = [[UIWindow alloc] initWithFrame:[UIScreen 
    mainScreen].bounds]; 
     self.alertWindow.rootViewController = [[UIViewController alloc] init]; 

     id<UIApplicationDelegate> delegate = [UIApplication sharedApplication].delegate; 
     // Applications that does not load with UIMainStoryboardFile might not have a window property: 
     if ([delegate respondsToSelector:@selector(window)]) { 
      // we inherit the main window's tintColor 
      self.alertWindow.tintColor = delegate.window.tintColor; 
     } 

     // window level is above the top window (this makes the alert, if it's a sheet, show over the keyboard) 
     UIWindow *topWindow = [UIApplication sharedApplication].windows.lastObject; 
     self.alertWindow.windowLevel = topWindow.windowLevel + 1; 

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

    @end 

Answer 1

最后，我已经找到了解决办法。经过一些实验后，我意识到，设置tintColor财产为UIWindow结果在所有UIAlertActions改变tintColor在UIWindow呈现。所以，我已经改变了UIAlertController扩展的代码（注意：原始代码不是我的，我在SoF上发现它，这要感谢它的作者），我用这种方式显示我的提醒：

#import "UIAlertController+WMC.h" 

@implementation UIAlertController (Private) 

@dynamic alertWindow; 

- (void)setAlertWindow:(UIWindow *)alertWindow { 
    objc_setAssociatedObject(self, @selector(alertWindow), alertWindow, OBJC_ASSOCIATION_RETAIN_NONATOMIC); 
} 

- (UIWindow *)alertWindow { 
    return objc_getAssociatedObject(self, @selector(alertWindow)); 
} 

@end 

@implementation UIAlertController (WMC) 

- (void)show { 
    [self show:YES]; 
} 

- (void)show:(BOOL)animated { 
    self.alertWindow = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds]; 
    self.alertWindow.rootViewController = [[UIViewController alloc] init]; 

    // window level is above the top window (this makes the alert, if it's a sheet, show over the keyboard) 
    UIWindow *topWindow = [UIApplication sharedApplication].windows.lastObject; 
    self.alertWindow.windowLevel = topWindow.windowLevel + 1; 

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

- (void)viewDidDisappear:(BOOL)animated { 
    [super viewDidDisappear:animated]; 

    // precaution to insure window gets destroyed 
    self.alertWindow.hidden = YES; 
    self.alertWindow = nil; 
} 

我刚刚做的是删除了继承主窗口tintColor的部分。呈现警报的这种复杂方式是我的项目中导致架构不良的结果。感谢所有评论员对这个问题感兴趣。

Answer 2

试试这个代码

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Title" message:@"Title Message" preferredStyle:UIAlertControllerStyleActionSheet]; 

    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:NSLocalizedString(@"Cancel", @"Cancel action") style:UIAlertActionStyleCancel handler:^(UIAlertAction *action){ 
     NSLog(@"Cancle Tapped"); 
     [alertController dismissViewControllerAnimated:YES completion:nil]; 
    }]; 

    [alertController addAction:cancelAction]; 

    UIAlertAction *yesAction = [UIAlertAction actionWithTitle:NSLocalizedString(@"Yes", @"Yes action") style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){ 
     NSLog(@"Yes Tapped"); 
    }]; 
    [alertController addAction:yesAction]; 

    UIAlertAction *noAction = [UIAlertAction actionWithTitle:NSLocalizedString(@"No", @"No action") style:UIAlertActionStyleDefault handler:^(UIAlertAction *action){ 
     NSLog(@"No Tapped"); 
    }]; 
    [alertController addAction:noAction]; 
    [self presentViewController:alertController animated:YES completion:nil];