如何取消UIView的旋轉塊動畫

Question

（

- (void)viewDidLoad 
{ 
[super viewDidLoad]; 
label = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 100, 50)]; 
label.layer.cornerRadius = 5.0f; 
label.text = @"hello world"; 
label.textAlignment = NSTextAlignmentCenter; 
[self.view addSubview:label]; 
[label release]; 
[self startAnimation]; 

UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect]; 
btn.frame = CGRectMake(0, 0, 60, 30); 
[btn addTarget:self action:@selector(btnPressed:) forControlEvents:UIControlEventTouchUpInside]; 
[self.view addSubview:btn]; 
} 

- (void)startAnimation 
{ 
CGAffineTransform transForm = CGAffineTransformMakeRotation(angel * M_PI/180.0f); 
[UIView animateWithDuration:0.1f delay:0.0f options:UIViewAnimationOptionCurveLinear animations:^(void){ 
    label.transform = transForm; 
} completion:^(BOOL finished) { 
    NSLog(@"1"); 
    angel = angel + 5; 
    [self startAnimation]; 
}]; 
} 

- (void)btnPressed:(id)sender 
{ 
    //method 1 :[label.layer removeAllAnimations]; not work... 
//method 2 : CGAffineTransform transForm = CGAffineTransformMakeRotation(M_PI/180.0f); 
//label.transform = transForm;  not work... 
} 

）

我旋轉的標籤，現在我想取消它，我搜索的網站可能的問題，並發現了大約兩個解決方案，我試過了，但是這兩個解決方案不起作用。

Answer 1

當您使用[label.layer removeAllAnimations]時，動畫不會停止，因爲無論finished變量的值是多少，都會調用[self startAnimation]。即使您取消了動畫，這也會導致動畫繼續。

您應該在動畫完成塊更改爲以下：

- (void)startAnimation 
{ 
    CGAffineTransform transForm = CGAffineTransformMakeRotation(angel * M_PI/180.0f); 
    [UIView animateWithDuration:0.1f delay:0.0f options:UIViewAnimationOptionCurveLinear  animations:^(void){ 
    label.transform = transForm; 
    } completion:^(BOOL finished) { 
    if (finished) { 
     NSLog(@"1"); 
     angel = angel + 5; 
     [self startAnimation]; 
    } 
    }]; 
} 

使用[label.layer removeAllAnimations]在btnPressed