修改UISearchBar的背景

5.0之前：

思路：将原来的背景删除掉，添加新的

代码：

for(UIView *subView  in   searchBar.subviews){//NSLog(@"subView:%@",subView);if([subView isKindOfClass:NSClassFromString(@"UISearchBarBackground")]){[subView removeFromSuperview];}}UIImage *searchBarBackImage = [UIImage imageNamed:@"searchbar_bg"];searchBarBackImage.frame = searchBar.frame;searchBarBackImage.userInteractionEnabled = YES;[searchBar  insertSubview:searchBarBackImage atIndex:0];

5.0之后：

[searchBar setBackgroundImage:[UIImage imageNamed:@"searchbar_bg"]];