ios - CALayer 子类不对属性更改进行动画处理

Question

我有一个 CALayer 子类，带有浮点 animAngle 作为标记为 @dynamic 的属性。我已经为子类实现了方法 actionForKey、initWithLayer、needsDisplayForKey 和 drawInContext。actionForKey的定义如下

- (id<CAAction>)actionForKey:(NString *)event {
    if([event isEqualToString:@"animAngle"]) {
        return [self animationForKey:event];
    }
    return [super actionForKey:event];
}

和

- (CABasicAnimation *)animationForKey:(NSString *)key
{
    NSString *animValue = [[self presentationLayer] valueForKey:key];// Logs as 0
    CABasicAnimation *anim;

    if([key isEqualToString:@"animAngle"]) {
        anim = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
        anim.repeatCount = HUGE_VAL;
        anim.autoreverses = YES;
        //anim.fromValue = [[self presentationLayer] valueForKey:key]; // setting animation value from layer property as in here does not work.
        anim.fromValue = [NSNumber numberWithFloat:0.5f];            // This works
    }
    anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
    anim.duration = 0.11;
    return anim;
}

在其他类中:

myCASublayer.animAngle = 0.5f;

返回的 CABasicAnimation 无法正确使用图层“animAngle”属性。我在这里可能做错了什么？

Answer 1

CocoaHeads Session: Rob Napier on Animating Custom Layer Properties是关于自定义动画的一个很好的介绍。

CALayers 讨厌绘制 ;)