在开发过程中，有时候系统给的searchBar和项目的风格不相同，有时候需要圆弧边角的searchBar，如图：

屏幕快照 2016-08-19 下午6.00.18.png

现在分享他的实现。
方法一：用系统自带的searchBar：

    UISearchBar *searchBar = [[UISearchBar alloc] init];
    searchBar.delegate = self;
    searchBar.frame = CGRectMake(10, 28, SCREEN_WIDTH - 20, 32);
    searchBar.backgroundColor = [UIColor redColor];
    searchBar.layer.cornerRadius = 16;
    searchBar.layer.masksToBounds = YES;
    [searchBar.layer setBorderWidth:8];
    [searchBar.layer setBorderColor:[UIColor whiteColor].CGColor];  //设置边框为白色
    searchBar.placeholder = @"请输入关键词来查找房源";
    [self.view addSubview:searchBar];

方法二：用UITextField改装成searchBar：

UIView *searchView = [[UIView alloc] initWithFrame:CGRectMake(0, 64, self.view.frame.size.width, 40*(self.view.frame.size.height/568))];
searchView.backgroundColor = [UIColor clearColor];

UIImageView *searchBg = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"citySelectbg"]];
searchBg.frame = CGRectMake(0, 0, searchView.frame.size.width, searchView.frame.size.height);
[searchView addSubview:searchBg];

//搜索框
_searchText = [[UITextField alloc]initWithFrame:CGRectMake(30*(self.view.frame.size.width/320), 0, self.view.frame.size.width-30, searchView.frame.size.height)];
_searchText.backgroundColor = [UIColor greenColor];
_searchText.font = [UIFont systemFontOfSize:13];
_searchText.placeholder  = @"请输入城市名称或首字母查询";
_searchText.returnKeyType = UIReturnKeySearch;
_searchText.textColor    = [UIColor colorWithRed:58/255.0 green:58/255.0 blue:58/255.0 alpha:1];
_searchText.delegate     = self;
[_searchText addTarget:self action:@selector(textChange:) forControlEvents:UIControlEventEditingChanged];
[searchView addSubview:_searchText];
[self.view addSubview:searchView];

第二个方法实现的界面如图：

屏幕快照 2016-08-19 下午6.14.18.png

把绿色改成clearColor后：

屏幕快照 2016-08-19 下午6.16.11.png

@"citySelectbg"：

citySelectbg@2x.png