- (void)viewDidLoad {
    [super viewDidLoad];
   
    for (NSInteger i=0; i<5; i++) {
        [self itemViewWithOne:72*i*M_PI/180.0 two:72*(i+1)*M_PI/180.0];
    }
}
- (UIView *)bgView
{
    if (!_bgView) {
        _bgView = [[UIView alloc] init];
        _bgView.backgroundColor = [UIColor grayColor];
        _bgView.bounds = CGRectMake(0, 0, 100, 100);
        _bgView.center = self.view.center;
        [self.view addSubview:_bgView];
        
    }
    return _bgView;
}
- (void)itemViewWithOne:(CGFloat)starAngle two:(CGFloat)endAngle
{
    
    
    /*让半径等于期望半径的一半  lineWidth等于期望半径 就可以画圆*/
    
    CAShapeLayer *layer = [CAShapeLayer layer];
    
    UIBezierPath *bezierPath = [UIBezierPath bezierPath];
    [bezierPath addArcWithCenter:CGPointMake(50,50) radius:25 startAngle:starAngle endAngle:endAngle clockwise:YES];
    
    layer.path = bezierPath.CGPath;
//    bezierPath.lineCapStyle = kCGLineCapButt;

    
    layer.lineWidth = 50;
    UIColor *color = [UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0 blue:arc4random()%256/255.0 alpha:1];
//    UIColor *color1 = [UIColor colorWithRed:arc4random()%256/255.0 green:arc4random()%256/255.0 blue:arc4random()%256/255.0 alpha:1];

    
    layer.strokeColor = color.CGColor;
    // 最好 为clearColor 设置颜色是方便观察
    layer.fillColor = [UIColor yellowColor].CGColor;

    //默认
    layer.lineCap = kCALineCapButt;
    [self.bgView.layer addSublayer:layer];
    
    CABasicAnimation *basic = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    basic.duration = 1.1;
    basic.fromValue = @(0.1f);
    basic.toValue = @(1.0f);
    [layer addAnimation:basic forKey:@"basic"];
    
}