今天因为工程里面的view设置的是左上边没有圆角，所以特别写了一个UIiView的分类方法，来实现UIview的某一边带有圆角

方法如下：
.h里

import <UIKit/UIKit.h>

typedef NS_ENUM(NSInteger,UILayoutCornerRadiusType) {
UILayoutCornerRadiusTop = 0,
UILayoutCornerRadiusLeft = 1,
UILayoutCornerRadiusBottom = 2,
UILayoutCornerRadiusRight = 3,
UILayoutCornerRadiusAll = 4,
UILayoutCornerdeleteTopleft = 5,
};
@interface UIView (CornerRadius)
/**

• @author
• 设置不同边的圆角
• @param sideType 圆角类型
• @param cornerRadius 圆角半径
  */
  -(void)UILayoutCornerRadiusType:(UILayoutCornerRadiusType)radiusType withCornerRadius:(CGFloat)cornerRadius;
  @end

.m里

import "UIView+CornerRadius.h"

@implementation UIView (CornerRadius)

• (void)UILayoutCornerRadiusType:(UILayoutCornerRadiusType)sideType withCornerRadius:(CGFloat)cornerRadius
  {

  CGSize cornerSize = CGSizeMake(cornerRadius, cornerRadius);
  UIBezierPath *maskPath;

  switch (sideType) {
  case UILayoutCornerRadiusTop:
  {
  maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds
  byRoundingCorners:(UIRectCornerTopLeft|UIRectCornerTopRight)
  cornerRadii:cornerSize];
  }
  break;
  case UILayoutCornerRadiusLeft:
  {
  maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds
  byRoundingCorners:(UIRectCornerTopLeft|UIRectCornerBottomLeft)
  cornerRadii:cornerSize];
  }
  break;
  case UILayoutCornerRadiusBottom:
  {
  maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds
  byRoundingCorners:(UIRectCornerBottomLeft|UIRectCornerBottomRight)
  cornerRadii:cornerSize];
  }
  break;
  case UILayoutCornerRadiusRight:
  {
  maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds
  byRoundingCorners:(UIRectCornerTopRight|UIRectCornerBottomRight)
  cornerRadii:cornerSize];
  }
  break;
  case UILayoutCornerdeleteTopleft:
  {
  maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds
  byRoundingCorners:(UIRectCornerTopRight|UIRectCornerBottomRight|UIRectCornerBottomLeft)
  cornerRadii:cornerSize];
  }
  break;
  default:
  {
  maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds
  byRoundingCorners:UIRectCornerAllCorners
  cornerRadii:cornerSize];
  }
  break;
  }

  // Create the shape layer and set its path
  CAShapeLayer *maskLayer = [CAShapeLayer layer];
  maskLayer.frame = self.bounds;
  maskLayer.path = maskPath.CGPath;

  // Set the newly created shape layer as the mask for the image view's layer
  self.layer.mask = maskLayer;

  [self.layer setMasksToBounds:YES];
  }
  @end

//调用

• (void)viewDidLoad {
  [super viewDidLoad];

  UIView *whiteView =[[UIView alloc]init];
  whiteView.backgroundColor = [UIColor whiteColor];
  whiteView.frame = CGRectMake(30, 300, 200, 200);
  [whiteView UILayoutCornerRadiusType:5 withCornerRadius:3];
  [self.view addSubview:whiteView];
  }
  此处声明一下：可以修改代码，让其中三边有圆角，只需要添加类型然再在Case里添加 其实主要是添加 UIRectCornerTopRight|UIRectCornerBottomRight|UIRectCornerBottomLeft这里面的类型