/** SearchBar开始编辑 */- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar {    // 隐藏导航栏    [self.navigationController setNavigationBarHidden:YES animated:YES];        // 显示遮罩    UIView *cover = [[UIView alloc] init];    cover.backgroundColor = [UIColor blackColor];    cover.alpha = 0.2;    cover.frame = self.cityTableView.frame;    cover.tag = DJCoverTag;        // 由于UIView 不是UIControl,所以没有addTarget方法，可以使用UITapGestureRecognizer代替    // 当conver被点击时，移除第一响应者    [cover addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:searchBar action:@selector(resignFirstResponder)]];        [self.view addSubview:cover];}/** SearchBar结束编辑 */- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar {    // 显示导航栏    [self.navigationController setNavigationBarHidden:NO animated:YES];    // 隐藏遮罩    [[self.view viewWithTag:DJCoverTag] removeFromSuperview];    }