viewController.m
#import "ViewController.h"
#import "TBCycleView.h"
@interface ViewController ()
@property (weak, nonatomic) IBOutlet TBCycleView *cycleView;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (IBAction)slider:(UISlider *)sender {
self.cycleView.label.text = [NSString stringWithFormat:@"%.2f%%", sender.value*100];
[self.cycleView drawProgress:sender.value];
}
@end
TBCycleView.h
#import@interface TBCycleView : UIView
@property (nonatomic, strong) UILabel *label;
- (void)drawProgress:(CGFloat )progress;
@end
TBCycleView.m
#import "TBCycleView.h"
@interface TBCycleView ()
@property (nonatomic, assign) CGFloat progress;
@property (nonatomic, strong) CAShapeLayer *progressLayer;
@end
@implementation TBCycleView
- (UILabel *)label
{
if (_label == nil) {
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
label.textAlignment = NSTextAlignmentCenter;
label.center = CGPointMake(self.frame.size.width / 2, self.frame.size.height / 2);
[self addSubview:label];
_label = label;
}
return _label;
}
- (void)drawProgress:(CGFloat )progress
{
_progress = progress;
_progressLayer.opacity = 0;
[self setNeedsDisplay];
}
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect {
[self drawCycleProgress];
}
- (void)drawCycleProgress
{
CGPoint center = CGPointMake(100, 100);
CGFloat radius = 90;
CGFloat startA = - M_PI_2; //设置进度条起点位置
CGFloat endA = -M_PI_2 + M_PI * 2 * _progress; //设置进度条终点位置
//获取环形路径（画一个圆形，填充色透明，设置线框宽度为10，这样就获得了一个环形）
_progressLayer = [CAShapeLayer layer];//创建一个track shape layer
_progressLayer.frame = self.bounds;
_progressLayer.fillColor = [[UIColor clearColor] CGColor]; //填充色为无色
_progressLayer.strokeColor = [[UIColor redColor] CGColor]; //指定path的渲染颜色,这里可以设置任意不透明颜色
_progressLayer.opacity = 1; //背景颜色的透明度
_progressLayer.lineCap = kCALineCapRound;//指定线的边缘是圆的
_progressLayer.lineWidth = 10;//线的宽度
UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:center radius:radius startAngle:startA endAngle:endA clockwise:YES];//上面说明过了用来构建圆形
_progressLayer.path =[path CGPath]; //把path传递給layer，然后layer会处理相应的渲染，整个逻辑和CoreGraph是一致的。
[self.layer addSublayer:_progressLayer];
//生成渐变色
CALayer *gradientLayer = [CALayer layer];
//左侧渐变色
CAGradientLayer *leftLayer = [CAGradientLayer layer];
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)[UIColor yellowColor].CGColor, (id)[UIColor greenColor].CGColor];
[gradientLayer addSublayer:leftLayer];
//右侧渐变色
CAGradientLayer *rightLayer = [CAGradientLayer layer];
rightLayer.frame = CGRectMake(self.bounds.size.width / 2, 0, self.bounds.size.width / 2, self.bounds.size.height);
rightLayer.locations = @[@0.3, @0.9, @1];
rightLayer.colors = @[(id)[UIColor yellowColor].CGColor, (id)[UIColor redColor].CGColor];
[gradientLayer addSublayer:rightLayer];
[gradientLayer setMask:_progressLayer]; //用progressLayer来截取渐变层
[self.layer addSublayer:gradientLayer];
}
@end
