uisearchBar 支持空搜索

//支持空搜索

- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar

{

    UITextField *searchBarTextField =nil;

    NSArray *views = ([[[UIDevicecurrentDevice] systemVersion]floatValue] < 7.0) ? searchBar.subviews : [[searchBar.subviewsobjectAtIndex:0]subviews];

    for (UIView *subviewin views)

    {

        if ([subviewisKindOfClass:[UITextFieldclass]])

        {

            searchBarTextField = (UITextField *)subview;

            break;

        }

    }

    searchBarTextField.enablesReturnKeyAutomatically =NO;

}