在导航栏上放UISearchBar并且做圆角

UIView *titleView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 150, 35)]; //allocate titleView
        UIColor *color =   self .navigationController.navigationBar.tintColor;
        [titleView setBackgroundColor:color];

        UISearchBar *searchBar = [[UISearchBar alloc] init];
        searchBar.delegate = self ;
        searchBar.frame = CGRectMake(0, 0, 150, 35);
        searchBar.backgroundColor = color;
        searchBar.layer.cornerRadius = 18;
        searchBar.layer.masksToBounds = YES ;
        [titleView addSubview:searchBar];

        //Set to titleView
        self .navigationItem.titleView = titleView; 片:屏幕快照 2014-01-17 下午2.30.12.png