在iOS 11之前設(shè)置button的圓角，使用的方法如下

 btn.layer.cornerRadius = 15;
 btn.layer.masksToBounds = YES;
//這個(gè)方法設(shè)置的圓角是針對(duì)于四個(gè)圓角一起設(shè)置，對(duì)于個(gè)性化UI樣式來說不好使用

iOS 11之后button新增了一個(gè)屬性 maskedCorners

typedef NS_OPTIONS (NSUInteger, CACornerMask)
{
  kCALayerMinXMinYCorner = 1U << 0,      //左上角
  kCALayerMaxXMinYCorner = 1U << 1,      //右上角
  kCALayerMinXMaxYCorner = 1U << 2,      //左下角
  kCALayerMaxXMaxYCorner = 1U << 3,      //右下角
};

@property CACornerMask maskedCorners
  CA_AVAILABLE_STARTING (10.13, 11.0, 11.0, 4.0);

使用方式如下

    UIButton *btn = [[UIButton alloc] initWithFrame:CGRectMake(50, 100, 300, 50)];
    [self.view addSubview:btn];
    btn.backgroundColor = [UIColor redColor];
    [btn setTitle:@"button" forState:UIControlStateNormal];
    [btn setTitleColor:[UIColor greenColor] forState:UIControlStateNormal];
    btn.layer.cornerRadius = 15;
    btn.layer.maskedCorners = kCALayerMinXMinYCorner;

FCD4ACD1-024D-4415-B9C5-374BB32D1991.png

//四個(gè)角
btn.layer.maskedCorners = kCALayerMaxXMinYCorner | kCALayerMaxXMaxYCorner | kCALayerMinXMaxYCorner | kCALayerMinXMinYCorner;

C64D0531-20CA-4AE5-AEE9-591919A03258.png

mark?。?！