objective-c uisearchbar一次只允许一个字符

I have created the following code but there's still one thing that's bugging me. For some reason, when I press any key on the keyboard, it immediately goes away, my cancel bar is disabled, but the code works and it correctly sorts and displays the cells in my table view that have those letters that the user typed in, though only one at a time. Is there something I'm missing? Thanks.I have created the following code but there's s