直接上代码
UIButton * button = [UIButton buttonWithType:UIButtonTypeCustom];
button.frame = CGRectMake(100, 100, 100, 50);
[button setTitle:@"点我啊" forState:UIControlStateNormal];
button.backgroundColor = [UIColor redColor];
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:button.bounds byRoundingCorners:UIRectCornerBottomLeft|UIRectCornerBottomRight cornerRadii:CGSizeMake(10.0, 10.0)];
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame = button.bounds;
maskLayer.path = maskPath.CGPath;
button.layer.mask = maskLayer;
[self.view addSubview:button];
