用CGAffineTransformIdentity逆时针转为顺时针方向

Question

我有一个电话轮。在发言中，它以动画的形式出现在他的位置上。

直到角度小于180°，它会顺时针返回。没问题，用此代码：

 - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { 
[UIView setAnimationBeginsFromCurrentState:YES]; 
[UIView beginAnimations:nil context:NULL]; 
[UIViewsetAnimationDuration:0.5]; 
wheel.transform = CGAffineTransformIdentity; 
[UIView commitAnimations]; 
}

但它出错后继续旋转完成转。

我试图做出动画像这样：

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { 
[UIView setAnimationBeginsFromCurrentState:YES]; 
[UIView beginAnimations:nil context:NULL]; 
[UIView setAnimationDuration:0.2]; 
wheel.transform = CGAffineTransformRotate(wheel.transform, degreesToRadians(-130)); 
[UIView commitAnimations]; 
[self performSelector:@selector(animatewheelViewToCenter) withObject:nil afterDelay:0.3]; 
} 

- (void)animatewheelViewToCenter{ 
[UIView setAnimationBeginsFromCurrentState:YES]; 
[UIView beginAnimations:nil context:NULL]; 
[UIViewsetAnimationDuration:0.3]; 
wheel.transform = CGAffineTransformIdentity; 
[UIView commitAnimations]; 
}

它的工作原理，但动画不是流体;该变化是可见的。

Answer 1

我不确定touchesEnded（根据旋转角度）是什么状态，而我正在琢磨你选择degreesToRadians（-130）来尝试部分地完成它，并期望下一个方法完成剩下的工作。这应该是一个更好的解决方案，希望能产生你期待的结果。我不确定什么是卡特兰，为什么你在旋转，所以我只是旋转轮子。

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { 
    [UIView setAnimationBeginsFromCurrentState:YES]; 
    [UIView beginAnimations:nil context:NULL]; 
    [UIView setAnimationDuration:0.2]; 
    wheel.transform = CGAffineTransformMakeRotation(degreesToRadians(-130)); 
    // I would recommend that the degrees you rotate be half of whatever your rotation is. 
    // this would make the wheel rotate to the home position more evenly 
    [UIView setAnimationDelegate:self]; 
    [UIView setAnimationDidStopSelector:@selector(animatewheelViewToCenter:finished:context:)]; 
    [UIView commitAnimations]; 
} 

- (void)animatewheelViewToCenter:(NSString *)animationID finished:(NSNumber *)finished context:(id)context { 
    [UIView setAnimationBeginsFromCurrentState:YES]; // you might need to make this NO 
    [UIView beginAnimations:nil context:NULL]; 
    [UIViewsetAnimationDuration:0.2]; 
    wheel.transform = CGAffineTransformIdentity; 
    [UIView commitAnimations]; 
} 

编辑：其实，我很可能会令旋转（在本例-130度）比一半会略多，因为CGAffineTransformIdentity是要去走最短路径回到正规，所以如果你完全按照1/2的方式走，它可能不会沿着你想要的正确方向（顺时针或逆时针）。