seachBar=[[ UISearchBar alloc] init];
//修改搜索框背景
seachBar.backgroundColor =[UIColor clearColor ];
//去掉搜索框背景
//1.
[[searchbar. subviews objectAtIndex : 0 ]removeFromSuperview ];
//2.
for ( UIView *subview in seachBar. subviews) 
{  
if ([subview isKindOfClass :NSClassFromString ( @"UISearchBarBackground" )])
{  
[subview removeFromSuperview ];  
break;  
}  
} 
//3自定义背景
UIImageView *p_w_picpathView = [[UIImageView alloc ] initWithImage :[UIImage p_w_picpathNamed : @"40-di.png" ]];
    [mySearchBar insertSubview:p_w_picpathView atIndex: 1];
    [p_w_picpathView release];
//4输入搜索文字时隐藏搜索按钮，清空时显示
- ( BOOL)searchBarShouldBeginEditing:( UISearchBar *)searchBar {  
searchBar. showsScopeBar = YES;  
[searchBar sizeToFit];  
[searchBar setShowsCancelButton : YES animated : YES ];  
return YES ;  
}  
- ( BOOL)searchBarShouldEndEditing:( UISearchBar *)searchBar {  
searchBar. showsScopeBar = NO;  
[searchBar sizeToFit];  
[searchBar setShowsCancelButton : NO animated : YES ];  
return YES ;  
}  
//改变搜索按钮文字
// 改变UISearchBar 取消按钮字体
for( id cc in [searchBar subviews])
    {
if ([cc isKindOfClass :[ UIButton class ]])
        {
            UIButton *btn = ( UIButton *)cc;
            [btn setTitle : @" 搜索 "   forState :UIControlStateNormal ];
        }
    }