如何在视图的图层颜色发生变化时使不同的颜色外观 [英] How to make the different colour appearance while layer color of the view is changing

问题描述

我正在做一些自定义下载进度栏（子类） UIButton （或）我也可以在 UIView ，一切都很好，现在我想改变标题的颜色作为收益的进度，例如你可以在下面的图片中看到显示我现在得到的，

I am doing some custom download progresses bar in side the (subclassed) UIButton (or) i can also do that in UIView, every thing is fine, now i want change the colour of the title as the progress the proceeds, for example as u can see in the below image shows what is now i am getting,

我想要的是如下图像

我希望在下载过程中将标题的颜色更改为白色或其他颜色，有什么方法我可以做，任何示例代码这个。

i want change the color of the title to white or some other color as download proceeds, is there any way i can do, any sample code for this.

我通过使用以下代码实现这一目标

i am achieving this by using below code

 - (void)drawInContext:(CGContextRef)progressContext
  {

     CGContextSetFillColorWithColor(progressContext, self.progressLayerColor.CGColor);
     CGMutablePathRef Path = CGPathCreateMutable();
     CGRect boundsRect = self.bounds;
     CGPathMoveToPoint(Path, NULL, boundsRect.origin.x, boundsRect.origin.y);

     CGPathAddRect(Path, NULL, CGRectMake(0, 0, self.progress, 35));
     CGPathCloseSubpath(Path);
     CGContextAddPath(progressContext, Path);
     CGContextFillPath(progressContext);
     CGContextSetBlendMode(progressContext, kCGBlendModeClear);
     CGContextFillPath(progressContext);

     CGPathRelease(Path);

  }

推荐答案

随着帮助@jrturton建议我能够制作这种进度条吧，

With the help of what @jrturton suggested i am able to make this kind of progress bar,

CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame = _labelGreen.bounds;//it the label on top with green background and white text color
CGMutablePathRef mutPath = CGPathCreateMutable();
CGPathMoveToPoint(mutPath, NULL, 0, 0);
CGPathAddRect(mutPath, NULL, CGRectMake( 0, 0, progress, _labelGreen.frame.size.height)); //as the progress cganges the width of mask layer also changes
maskLayer.path = mutPath;//set the path

_labelGreen.layer.mask = maskLayer;

结果输出将如下图所示

the resulted output will be like below image

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