圖
//----
searchController.delegate = self;
// --searchbar的代理方法
- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar
{
// --取消按鈕
searchBar.showsCancelButton = YES;
UIButton *btn = [searchBar valueForKey:@"_cancelButton"];
[btn setTitle:@"取消" forState:UIControlStateNormal];
return YES;
}