给Button设置圆角

//UIButtonTypeRoundedRect 四个角是圆弧形状

UIButton *button = [UIButton
buttonWithType:UIButtonTypeRoundedRect];

//设置圆角

[button.layer setMasksToBounds:YES];

[button.layer setCornerRadius:20.0];

//设置边框的宽度(1.0的效果就很不错了)


[button.layer
setBorderWidth:1.0];