CoreAnimation导致内存泄漏

案例:

执行关键帧动画如下:

    CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];
    anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];
    anim.keyPath = @"position";
    CGPoint controlPoint = CGPointMake(startPoint.x+50, self.endPoint.y+50);
    
    UIBezierPath *path = [UIBezierPath bezierPath];
    [path moveToPoint:startPoint];
    [path addQuadCurveToPoint:self.endPoint controlPoint:controlPoint];
    
    anim.path = path.CGPath;
    anim.duration = [self durationWithStartPoint:startPoint controlPoint:controlPoint endPoint:self.endPoint];
    anim.delegate = self;
    anim.fillMode = kCAFillModeForwards;
    anim.removedOnCompletion = NO;
    [self.playIcon.layer addAnimation:anim forKey:@"animationTest"];

- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{
   //do something
}

self对象无法释放.

分析:

查询CAAnimation的delegate:

/* The delegate of the animation. This object is retained for the
 * lifetime of the animation object. Defaults to nil. See below for the
 * supported delegate methods. */

@property(nullable, strong) id <CAAnimationDelegate> delegate;

在动画的生命周期delegate都会被强引用.

一般情况执行完毕动画后,会自动释放.

/* When true, the animation is removed from the render tree once its
 * active duration has passed. Defaults to YES. */

@property(getter=isRemovedOnCompletion) BOOL removedOnCompletion;

但当设置为NO时,anim.removedOnCompletion = NO;的时候, 需要我们手动释放.

解决:

动画结束时,手动移除动画.

- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag{
    [self.playIcon.layer removeAnimationForKey:@"animationTest"];
    //do something
}

拓展:

类似也有UIWebView的delegate, 需要手动释放.