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核心动画:为什么我不能合成两个动画?

core-animation ios animation

P i · 技术社区 · 15 年前

我正试图制作一个轮子的动画

当手指停留>0.1秒时,车轮“弹出”,即I动画比例从1.0到1.2。

当手指移动时,轮子随之转动(只有当它被弹出时)。

但我遇到了一个问题:一旦它开始旋转,刻度就减小到1.0。

- (void) spin: (Direction) direction
{
 float thetaOld = thetaWheel;

 float k = (direction == AntiClockwise) ? -1 : 1;
 float t = 2 * M_PI * ( k / 12.0 );
 thetaWheel += t;

 CABasicAnimation * anim = [CABasicAnimation animationWithKeyPath:@"transform"];

 anim.fromValue = [NSNumber numberWithDouble: thetaOld];
 anim.toValue = [NSNumber numberWithDouble: thetaWheel];

 anim.valueFunction = [CAValueFunction functionWithName: kCAValueFunctionRotateZ];

 anim.timingFunction = [CAMediaTimingFunction functionWithName: kCAMediaTimingFunctionEaseInEaseOut]; 

 anim.duration = 0.1f;
 anim.fillMode = kCAFillModeForwards;
 anim.removedOnCompletion = NO;

 [self.wheelLayer addAnimation: anim forKey:@"transform"];
}

- (void) popOut
{
 CABasicAnimation * anim = [CABasicAnimation animationWithKeyPath:@"transform.scale"];

 anim.fromValue = [NSNumber numberWithDouble: 1.0];
 anim.toValue = [NSNumber numberWithDouble: 1.2];

 anim.timingFunction = [CAMediaTimingFunction functionWithName: kCAMediaTimingFunctionEaseInEaseOut]; 

 anim.duration = 0.25f;
 anim.fillMode = kCAFillModeForwards;
 anim.removedOnCompletion = NO;

 [self.wheelLayer addAnimation: anim forKey:@"transform.scale"];
}

// doesnt get used yet
- (void) popBack
{
 CABasicAnimation * anim = [CABasicAnimation animationWithKeyPath:@"transform.scale"];

 anim.fromValue = [NSNumber numberWithDouble: 1.2];
 anim.toValue = [NSNumber numberWithDouble: 1.0];

 anim.timingFunction = [CAMediaTimingFunction functionWithName: kCAMediaTimingFunctionEaseInEaseOut]; 

 anim.duration = 0.1f;
 anim.fillMode = kCAFillModeForwards;
 anim.removedOnCompletion = NO;

 [self.wheelLayer addAnimation: anim forKey:@"transform.scale"];
}

最后一个程序此时无法使用!所以我看不出是什么把比例缩小到1…

看起来第二个动画覆盖了第一个…

如何正确执行此操作?