iphone - 当我调用 [Timer isValid] 或 [Timer invalidate] 时，NSTimer 崩溃

Question

我的 iPhone 应用程序中有两个 NSTimer。DecreaseTimer 工作正常，但当我调用 [timerCountSeconds isValid] 或 [timerCountSeconds invalidate] 时，TimerCountSeconds 崩溃了。它们是这样使用的:

-(id)initialize { //Gets called, when the app launches and when a UIButton is pressed
 if ([timerCountSeconds isValid]) {
  [timerCountSeconds invalidate];
 } 
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { //Gets called, when you begin touching the screen
 //....
 if ([decreaseTimer isValid]) {
   [decreaseTimer invalidate];
  }
 timerCountSeconds = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(runTimer) userInfo:nil repeats:YES];
 //....
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {//Gets called, when you stop touching the screen(not if you press the UIButton for -(id)initialize)
 //...
 decreaseTimer = [NSTimer scheduledTimerWithTimeInterval:0.05 target:self selector:@selector(decrease) userInfo:nil repeats:YES];
 //...
}
-(void)comept3 { //Gets calles when you rubbed the screen a bit
    if ([timerCountSeconds isValid]) {
    [timerCountSeconds invalidate];
    }
}

我做错了什么？你能帮帮我吗？

Answer 1

您应该在invalidate 之后将NSTimer 对象设置为nil，因为invalidate 方法调用也会执行 release(根据 Apple 文档)。如果你不这样做，调用一个像 isValid 这样的方法可能会导致你的崩溃。