CAGradientLayer实现圆环的颜色渐变

效果图

函数代码：

#pragma mark彩色的圆

-(void)recordingCircleOverlayView

{

self.backgroundColor=[UIColorpurpleColor];

//根图层

CALayer*thelayer=[CALayerlayer];

thelayer.frame=CGRectMake(0,0,CGRectGetWidth(self.frame)/2.,CGRectGetWidth(self.frame)/2.);

thelayer.backgroundColor=[UIColorwhiteColor].CGColor;

[self.layeraddSublayer:thelayer];

//画圆

UIBezierPath*theCirclePath1=[UIBezierPathbezierPathWithArcCenter:CGPointMake(thelayer.position.x, thelayer.position.y)radius:90startAngle:M_PIendAngle:-M_PIclockwise:NO];

CAShapeLayer*theBigLayer=[CAShapeLayerlayer];

theBigLayer.path=theCirclePath1.CGPath;

theBigLayer.strokeColor=[UIColorpurpleColor].CGColor;

theBigLayer.fillColor=[UIColorclearColor].CGColor;

theBigLayer.lineWidth=5;

theBigLayer.strokeStart=0;

//分块颜色

CAGradientLayer*theGradien=[CAGradientLayerlayer];

theGradien.frame=thelayer.bounds;

theGradien.colors=@[

(__bridgeid)[UIColoryellowColor].CGColor,

(__bridgeid)[UIColorredColor].CGColor,

(__bridgeid)[UIColorblueColor].CGColor

];

theGradien.locations=@[@.25,@.5,@.8];

[thelayeraddSublayer:theGradien];

//遮罩

thelayer.mask=theBigLayer;

//动画

CABasicAnimation*baseAnim=[CABasicAnimationanimationWithKeyPath:@"strokeStart"];

baseAnim.fromValue=[NSNumbernumberWithFloat:0.];

baseAnim.toValue=[NSNumbernumberWithFloat:1.];

baseAnim.duration=5;

baseAnim.repeatCount=9;

[theBigLayeraddAnimation:baseAnimforKey:@"stro"];

}