UIButton *button = [[UIButton alloc] initWithFrame:CGRectMake(50, 60, 80, 40)];button.backgroundColor = [UIColor orangeColor];[self.view addSubview:button]; //這里設置的是左上和左下角UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:button.bounds byRoundingCorners:UIRectCornerBottomLeft | UIRectCornerTopLeft cornerRadii:CGSizeMake(8, 8)];CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];maskLayer.frame = button.bounds;maskLayer.path = maskPath.CGPath;button.layer.mask = maskLayer;