Question

我想在屏幕上显示警报时暂停屏幕，然后在警报解除时撤消暂停。我该怎么办？这是我的视图控制器：

- (void)viewDidLoad
{NSLog(@"viewDidLoad");
[super viewDidLoad];

[self generate];

[self.answer becomeFirstResponder];

UIAlertView *alert;
{alert = [[UIAlertView alloc]
          initWithTitle:@"Welcome to iCanMultiply!" 
          message:@"Tap 'Start' to start the game" 
          delegate: self
          cancelButtonTitle:@"Start" 
          otherButtonTitles: nil];
}

[alert show];
[alert release];

alertTimer = [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:@selector(showAlert) userInfo:nil repeats:YES];
}

-(void)showAlert {
    UIAlertView *alert = [[UIAlertView alloc] 
                      initWithTitle:@"Game Over" 
                      message:@"You ran out of time" 
                      delegate:self 
                      cancelButtonTitle:@"Try Again" 
                      otherButtonTitles: nil];

[alert show];
[alert release];
}

- (IBAction)submit:(id)sender {
int num = [answer.text intValue];


UIAlertView *alert;
if (num == label.tag)
{
    NSUInteger messageCount = [messagesCorrect count];
    int randomMessageIndex = arc4random() % messageCount;

    alert = [[UIAlertView alloc] 
             initWithTitle:@"Correct!" 
             message:[messagesCorrect objectAtIndex:randomMessageIndex]
             delegate:self 
             cancelButtonTitle:@"Next Question" 
             otherButtonTitles: nil];

    alert.tag = 1;

} else 
{
    NSUInteger messageCount = [messagesIncorrect count];
    int randomMessageIndex = arc4random() % messageCount;

    alert = [[UIAlertView alloc] 
             initWithTitle:@"Wrong!" 
             message:[messagesIncorrect objectAtIndex:randomMessageIndex]
             delegate:self 
             cancelButtonTitle:@"Try Again" 
             otherButtonTitles: nil];
    }

    [alert show];
    [alert release];
}

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if (alertView.tag == 1)
    {
        [self generate];

        answer.text = @"";
    }
}

-(void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex {

    }

请注意，我的App Delegate与我刚开始使用该应用程序时的相同。

Answer 1

抱歉，我没有看过你的代码，但一般来说这就是你暂停NSTimer的方式。

你设置了一个ivar（在你的.h中）：

NSTimer *theTimer;

当你想要开始时：

if (!theTimer) {
    theTimer = [NSTimer scheduledTimerWithTimeInterval:10 target:self selector:@selector(showAlert) userInfo:nil repeats:YES];
}

当你想要阻止它时

if (theTimer) {
    [theTimer invalidate];
    theTimer = nil;
}

如何在屏幕上显示警报时暂停应用程序？

1 个答案: