- (CAShapeLayer *)shapeLayer {

    if (!_shapeLayer) {

        _shapeLayer = [CAShapeLayer layer];

        CGRect rect = {,,,};

        //bezierPathWithOvalInRect圆形路径 bezierPathWithRect 方形路径

        UIBezierPath * path = [UIBezierPath bezierPathWithOvalInRect: rect];

        _shapeLayer.strokeColor = [UIColor orangeColor].CGColor;

        _shapeLayer.lineWidth = ;

        _shapeLayer.fillColor = [UIColor clearColor].CGColor;

        _shapeLayer.lineCap = kCALineCapRound;

        _shapeLayer.path = path.CGPath;

    }

    return _shapeLayer;

}

- (CAShapeLayer *)progressLayer {

    if (!_progressLayer) {

        _progressLayer = [CAShapeLayer layer];

        _progressLayer.frame = self.shapeLayer.bounds;

        _progressLayer.fillColor = [UIColor clearColor].CGColor;

        _progressLayer.strokeColor = [UIColor whiteColor].CGColor;

        _progressLayer.lineWidth = ;

        _progressLayer.lineCap = kCALineCapRound;

        CGRect rect = {,,,};

        UIBezierPath * path = [UIBezierPath bezierPathWithOvalInRect: rect];

        _progressLayer.path = path.CGPath;

    }

    return _progressLayer;

}

[self.view.layer addSublayer: self.shapeLayer];

    [self.view.layer addSublayer: self.progressLayer];

    CAGradientLayer * gradientLayer1 = [CAGradientLayer layer];

    gradientLayer1.frame = self.view.bounds;

    CGColorRef red = [UIColor redColor].CGColor;

    CGColorRef purple = [UIColor purpleColor].CGColor;

    CGColorRef yellow = [UIColor yellowColor].CGColor;

    CGColorRef orange = [UIColor orangeColor].CGColor;

    gradientLayer1.colors = @[(__bridge id)red,(__bridge id)purple,(__bridge id)yellow,(__bridge id)orange];

    gradientLayer1.locations = @[@0.3, @0.6,@0.8,@1.0];

    gradientLayer1.startPoint = CGPointMake(0.5, );

    gradientLayer1.endPoint = CGPointMake(0.5, );

    //一定要设置gradientLayer.mask = self.progressLayer;这样才能显示中间的内容，如果不设置mask，那么就只有渐变图层了

    gradientLayer1.mask = self.progressLayer;

    [self.view.layer addSublayer: gradientLayer1]; //添加渐变

- (IBAction)change:(UISlider * )sender {

    CGFloat cV = sender.value * ;

    [self updateProgressWithNumber: cV];

}

- (void)updateProgressWithNumber:(NSUInteger)number {

    [CATransaction begin];

    [CATransaction setAnimationTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn]];

    [CATransaction setAnimationDuration:0.5];

    self.progressLayer.strokeEnd =  number / 100.0;

    NSLog(@"%@",[NSString stringWithFormat:@"%@%%", @(number)]);

    [CATransaction commit];

}