使用前导入框架AVFoundation

- (void)viewDidLoad {
    [super viewDidLoad];
    UIView *view = [[UIView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];
    view.backgroundColor = [UIColor redColor];
    
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:UIRectCornerAllCorners cornerRadii:view.bounds.size];
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc]init];
    maskLayer.frame = view.bounds;
    maskLayer.path = maskPath.CGPath;
    view.layer.mask = maskLayer;
    
    [self.view addSubview:view];
}