objective-c - cancelPreviousPerformRequestsWithTarget 不工作

Question

我在一个类中使用这个方法来开始一个 Action :

[self performSelector:@selector(startRolling) withObject:nil afterDelay:0.1f];

为了阻止它，我正在使用:

[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(startRolling) object:nil];

但从未停止。

这两个调用都在同一个类和同一个线程中实现。

我也用过这个但是没有解决:

-(void)stopRolling
{
    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(startRolling) object:nil];
    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(commitAnimation) object:nil];

    [NSObject cancelPreviousPerformRequestsWithTarget:self];
    [[NSRunLoop currentRunLoop] cancelPerformSelectorsWithTarget:self];
}

我错过了什么？

谢谢。

---编辑---

要知道我正在使用的是不是主线程:

-(void)stopRolling
{
    if ([NSThread isMainThread])
        NSLog(@"Is Main Thread");

    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(startRolling) object:nil];
    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(commitAnimation) object:nil];

    [NSObject cancelPreviousPerformRequestsWithTarget:self];
    [[NSRunLoop currentRunLoop] cancelPerformSelectorsWithTarget:self];
}

什么时候工作正常，什么时候不总是在日志中出现是主线程。

正在执行我正在启动的选择器(startRolling 和 commitAnimations)的是使用 [UIView beginAnimation:context:) 的动画

有没有可能是这个原因？

这里是方法:

-(void)startRolling
{
    currentPic++;

    if (currentPic > count)
        currentPic = 1;

    [UIView beginAnimations:@"fadeIn" context:nil];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDuration:RDFadeInDelay];

    NSLog(@"RollUp: %@",[NSString stringWithFormat:@"RDInitialRollUp_%d",currentPic]);

    background.image = [UIImage imageNamed:[NSString stringWithFormat:@"RDInitialRollUp_%d.jpg",currentPic]];

    background.alpha = 1.0f;    

    [UIView commitAnimations];

}
- (void)animationDidStop:(NSString *)animationID finished:(NSNumber *) finished context:(void *) context
{
    if ([animationID isEqualToString:@"fadeIn"])
    {
        [self performSelector:@selector(commitAnimation) withObject:nil afterDelay:RDOnScreenDelay];
    }
    else
    {
        [self performSelector:@selector(startRolling) withObject:nil afterDelay:0.1f];

    }
}
-(void)commitAnimation
{
    [UIView beginAnimations:@"fadeOut" context:nil];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDuration:RDFadeOutDelay];

    background.alpha = 0.0f;    

    [UIView commitAnimations];
}
-(void)stopRolling
{
    if ([NSThread isMainThread])
        NSLog(@"Is Main Thread");

    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(startRolling) object:nil];
    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(commitAnimation) object:nil];

    [NSObject cancelPreviousPerformRequestsWithTarget:self];
    [[NSRunLoop currentRunLoop] cancelPerformSelectorsWithTarget:self];
}

正在使用 performOnMainThread 调用调用 stopRolling 方法的方法:

谢谢。

--编辑---

我已经根据建议修改了方法，但仍然无法正常工作:

-(void)stopRolling
{
    if ([NSThread isMainThread])
        NSLog(@"Is Main Thread");
    else
        NSLog(@"Is NOT Main Thread");

    [self.layer removeAllAnimations];

    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(startRolling) object:nil];
    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(commitAnimation) object:nil];

    [NSObject cancelPreviousPerformRequestsWithTarget:self];
    [[NSRunLoop currentRunLoop] cancelPerformSelectorsWithTarget:self];
}

我观察到，如果用户在执行图像之间的转换时点击屏幕是不起作用的。但是如果用户在图像出现在屏幕上时(2 秒内)点击屏幕，一切正常。

始终在主线程上。

:(我很绝望，这让程序因为内存而崩溃。

--编辑--

最后，我使用 BOOL 标志解决了问题。但我认为这是一个糟糕的解决方案，因为这必须没有。执行动画时会发生一些奇怪的事情，因为这仅在动画未执行时有效。

这适用于所有情况:

- (void)animationDidStop:(NSString *)animationID finished:(NSNumber *) finished context:(void *) context
{
    if (!mustAnimate) return;

    if ([animationID isEqualToString:@"fadeIn"])
    {
        [self performSelector:@selector(commitAnimation) withObject:nil afterDelay:RDOnScreenDelay];
    }
    else
    {
        [self performSelector:@selector(startRolling) withObject:nil afterDelay:0.1f];

    }
}
-(void)commitAnimation
{
    [UIView beginAnimations:@"fadeOut" context:nil];
    [UIView setAnimationDelegate:self];
    [UIView setAnimationDuration:RDFadeOutDelay];

    background.alpha = 0.0f;    

    [UIView commitAnimations];
}
-(void)stopRolling
{
    mustAnimate = NO;

    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(startRolling) object:nil];
    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(commitAnimation) object:nil];

}

谢谢你所做的一切。

Answer 1

如图所示更改传递给两个方法的参数，

[self performSelector:@selector(SampleMethod) withObject:self afterDelay:delayTime];     
[NSObject cancelPreviousPerformRequestsWithTarget:self];