i0S-CAShaperLayer结合UIBezierPath画

实例：

- (void)drawRoundView:(CGPoint)centerPoint withStartAngle:(CGFloat)startAngle withEndAngle:(CGFloat)endAngle withRadius:(CGFloat)radius {
    UIBezierPath *path = [UIBezierPath bezierPath];
    [path addArcWithCenter:centerPoint radius:radius startAngle:startAngle endAngle:endAngle  clockwise:YES];
    self.arcLayer = [CAShapeLayer layer];
    self.arcLayer.path = path.CGPath;
    self.arcLayer.strokeColor = [UIColor blueColor].CGColor;
    //arcLayer.strokeColor可设置画笔颜色
    self.arcLayer.lineWidth = 10;
    self.arcLayer.frame = self.view.bounds;
    self.arcLayer.fillColor = [UIColor clearColor].CGColor;
    [self.view.layer addSublayer:self.arcLayer];
    
//    动画显示圆则调用
    [self drawLineAnimation:self.arcLayer];
}

- (void)drawLineAnimation:(CALayer*)layer {
    CABasicAnimation *bas = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    bas.duration = 1;
    bas.fromValue = [NSNumber numberWithInteger:0];
    bas.toValue = [NSNumber numberWithInteger:1];
    [layer addAnimation:bas forKey:@"key"];
}