CAShapeLayer使用

UIView *showView = [[UIView alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];

[self.view addSubview:showView];

showView.backgroundColor = [UIColor whiteColor];

UIBezierPath *path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(100 / 2.f, 100 / 2.f)

radius:100 / 2.f

startAngle:0

endAngle:1.5*M_PI

clockwise:YES];

CAShapeLayer *layer = [CAShapeLayer layer];

layer.frame         = showView.bounds;                // 与showView的frame一致

layer.strokeColor   = [UIColor greenColor].CGColor;   // 边缘线的颜色

layer.fillColor     = [UIColor greenColor].CGColor;   // 闭环填充的颜色

layer.lineCap       = kCALineCapRound;               // 边缘线的类型

layer.path          = path.CGPath;                    // 从贝塞尔曲线获取到形状

layer.lineWidth     = 9.0f;                           // 线条宽度

layer.strokeStart   = 0.0f;

layer.strokeEnd     = 0.0f;

[showView.layer addSublayer:layer];

CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];

pathAnimation.duration = 5.0;

pathAnimation.fromValue = [NSNumber numberWithFloat:0.0f];

pathAnimation.toValue = [NSNumber numberWithFloat:1.0f];

[layer addAnimation:pathAnimation forKey:nil];