带渐变颜色的环形进度条

创建一个circleView，以后要用到环形进度条实例化之就可以

#import"cycleView.h"

@implementationcycleView

- (void)drawRect:(CGRect)rect

{

//使用CAShapeLayer绘制出渐变层，因为它只能指定两个点之间进行渐变，所以这里需要两个CAShapeLayer，左右各一个

//生成渐变色

CALayer*gradientLayer = [CALayerlayer];

//左侧渐变色

CAGradientLayer*leftLayer = [CAGradientLayerlayer];

leftLayer.frame=CGRectMake(0,0,self.bounds.size.width/2,self.bounds.size.height);

//分段设置渐变色

leftLayer.locations=@[@0.3,@0.9,@1];

leftLayer.colors=@[(id)[UIColoryellowColor].CGColor,(id)[UIColorgreenColor].CGColor];

[gradientLayeraddSublayer:leftLayer];

//右侧渐变色

CAGradientLayer*rightLayer = [CAGradientLayerlayer];

rightLayer.frame=CGRectMake(self.bounds.size.width/2,0,self.bounds.size.width/2,self.bounds.size.height);

//分段设置渐变色

rightLayer.locations=@[@0.3,@0.9,@1];

rightLayer.colors=@[(id)[UIColoryellowColor].CGColor,(id)[UIColorredColor].CGColor];

[gradientLayeraddSublayer:rightLayer];

CGPointcenter =CGPointMake(100,100);

CGFloatradius =90;

CGFloatstartA = -M_PI_2;

CGFloatendA = -M_PI_2+M_PI*2*_progress;

CAShapeLayer*progressLayer = [CAShapeLayerlayer];

progressLayer.frame=self.bounds;

progressLayer.fillColor= [UIColorclearColor].CGColor;

progressLayer.strokeColor= [UIColorredColor].CGColor;

progressLayer.opacity=1;

progressLayer.lineCap=kCALineCapRound;

progressLayer.lineWidth=10;

UIBezierPath*path = [UIBezierPathbezierPathWithArcCenter:centerradius:radiusstartAngle:startAendAngle:endAclockwise:YES];

progressLayer.path= path.CGPath;

[self.layeraddSublayer:progressLayer];

[gradientLayersetMask:progressLayer];

[self.layeraddSublayer:gradientLayer];

/*

//获取上下文

CGContextRef ctx = UIGraphicsGetCurrentContext();

//获取圆心的位置

CGPoint center = CGPointMake(100, 100);

//设置半径

CGFloat radius = 90;

//圆起始点位置

CGFloat startA = - M_PI_2;

//圆终点位置

CGFloat endA = - M_PI_2 + M_PI * 2 *_progress;

//

UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center radius:radius startAngle:startA endAngle:endA clockwise:YES];

//设置线条宽度

CGContextSetLineWidth(ctx, 10);

//设置描边颜色

[[UIColor blueColor] setStroke];

//把路径添加到上下文

CGContextAddPath(ctx, path.CGPath);

//渲染

CGContextStrokePath(ctx);

*/

}

//drawRect方法只在视图刚出现执行一次，所以需要使用[self setNeedDisplay];

- (void)drawProgress:(CGFloat)progress

{

_progress= progress;

[selfsetNeedsDisplay];

}

效果图：