ios开发之--调整UISearchBar的输入框的背景颜色

遍历UISearchBar的子视图，找到输入框坐在的view，添加背景颜色即可。

代码如下：

    UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(10, 22, kScreenW - 10, 30)];
    searchBar.tintColor = [UIColor darkGrayColor];
    searchBar.barTintColor = [UIColor whiteColor];
    searchBar.placeholder = @"请输入关键字";
    searchBar.searchBarStyle = UISearchBarStyleMinimal;
    [searchBar positionAdjustmentForSearchBarIcon:UISearchBarIconSearch];
    searchBar.delegate = self;
    [barView addSubview:searchBar];
    self.searchBar = searchBar;  

    // 改变UISearchBar内部输入框样式
    UIView *searchTextField = nil;
    if (kIOSVersion >= 7.0)
    {
        searchTextField = [[[self.searchBar.subviews firstObject] subviews] lastObject];
    }
    else
    {
        // iOS6以下版本searchBar内部子视图的结构不一样
        for(UIView *subview in self.searchBar.subviews)
        {
            if ([subview isKindOfClass:NSClassFromString(@"UISearchBarTextField")])
            {
                searchTextField = subview;
            }
        }
    }
    // 改变输入框背景色
    searchTextField.subviews[0].backgroundColor = [UIColor whiteColor];
    searchTextField.layer.cornerRadius = 5.0;