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];
        }
    }