Question

到目前为止，这是我的代码：

    CAGradientLayer *gradient = [CAGradientLayer layer];
    gradient.frame = twoDrums.bounds;
    gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor grayColor] CGColor], (id)[[UIColor blackColor] CGColor], nil];
    gradient.locations = [NSArray arrayWithObjects: [NSNumber numberWithFloat:0.00], [NSNumber numberWithFloat:0.70] , nil];
    [twoDrums.layer insertSublayer:gradient atIndex:0];

    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"colors"];
    animation.fromValue = [NSArray arrayWithObjects:(id)[[UIColor redColor] CGColor], (id)[[UIColor blackColor] CGColor], nil];
    animation.toValue = [NSArray arrayWithObjects:(id)[[UIColor blueColor] CGColor], (id)[[UIColor blackColor] CGColor], nil];
    animation.duration = 15.0;
    animation.removedOnCompletion = NO;
    animation.autoreverses = YES;
    animation.fillMode = kCAFillModeForwards;
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
    [gradient addAnimation:animation forKey:@"animateGradient"];

这是一个渐变，从红色/黑色变为蓝色/黑色再向后变化。我想做的是在同一个动画中从红色/黑色变为黄色/黑色到蓝色/黑色再到绿色/黑色等。

非常感谢任何帮助。谢谢，圣诞快乐！

Answer 1

我知道你要求多个动画，但这就是我最后只用一个渐变色变化的方法。也许你可以从中构建。

首先我像这样制作渐变层：

CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = _view.frame;
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor yellowColor] CGColor], (id)[[UIColor orangeColor] CGColor], nil];
UIView *gradientView = [[UIView alloc] initWithFrame:_view.frame];
[gradientView setBackgroundColor:[UIColor clearColor]];
[gradientView.layer insertSublayer:gradient atIndex:0];
[gradientView setHidden:NO];
[_window addSubview:gradientView];

然后我设置颜色变化的动画：

- (void)animateViewToTransparent:(UIView *)view {

NSArray *sublayers = [view.layer sublayers];
CAGradientLayer *gradientLayer = [sublayers objectAtIndex:0];

CABasicAnimation *gradientAnimation = [CABasicAnimation animationWithKeyPath:@"colors"];
gradientAnimation.toValue = [NSArray arrayWithObjects:(id)[[UIColor clearColor] CGColor], [[UIColor clearColor] CGColor], nil];
gradientAnimation.duration = 0.4f;
URAnimationDelegate *delegate = [[URAnimationDelegate alloc] init];
[gradientAnimation setDelegate:delegate];
[gradientLayer addAnimation:gradientAnimation forKey:@"colors"];

}

现在动画将起作用，但动画完成后颜色变化将不会停留。 URAnimationDelegate类的最后一步是设置layer.colors属性。

NSArray *sublayers = [_view.layer sublayers];
CAGradientLayer *gradientLayer = [sublayers objectAtIndex:0];
gradientLayer.colors = [NSArray arrayWithObjects:(id)[[UIColor clearColor] CGColor], [[UIColor clearColor] CGColor], nil];

Etvoilà！

Answer 2

使用CAAnimationGroup结束运行。因为每个动画都必须设置一个beginTime，所以它们不会同时启动。

如何使用多个颜色过渡为渐变设置动画？

2 个答案: