UIAlertView和UIAlertController标题不显示

Question

我创建了一个警告如下：

// UIAlertView
UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"WARNING" message:@"Are you sure you want to quit ?" delegate:nil cancelButtonTitle:@"Confirm" otherButtonTitles:@"Cancel", nil];
[alertView show];

// or UIAlertController
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"WARNING" message:@"Are you sure you want to quit ?" preferredStyle:UIAlertControllerStyleAlert];
[alertController addAction:[UIAlertAction actionWithTitle:@"Confirm" style:UIAlertActionStyleDefault handler:NULL]];
[alertController addAction:[UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:NULL]];
[self presentViewController:alertController animated:YES completion:NULL];

但两种效果都是这样的：

我尝试记录alert的标题，但结果为null：

我该如何解决这个问题？

Answer 1

他们两个都在我这边工作。

尝试使用此代码：

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"WARNING" message:@"Are you sure you want to quit ?" delegate:nil cancelButtonTitle:@"Confirm" otherButtonTitles:@"Cancel", nil];
    [alertView show];

    [self.view addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(grHandler)]];
}

-(void)grHandler{
    // UIAlertController
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"WARNING" message:@"Are you sure you want to quit ?" preferredStyle:UIAlertControllerStyleAlert];
    [alertController addAction:[UIAlertAction actionWithTitle:@"Confirm" style:UIAlertActionStyleDefault handler:NULL]];
    [alertController addAction:[UIAlertAction actionWithTitle:@"Cancel" style:UIAlertActionStyleCancel handler:NULL]];
    [self presentViewController:alertController animated:YES completion:NULL];
}

@end