iOS 重写pop跳转的方法

UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"back" style:UIBarButtonItemStylePlain target:self action:@selector(popController)];
self.navigationItem.leftBarButtonItem = backItem;</span>

<-(void)popController
{
[self.navigationController popToRootViewControllerAnimated:YES];
[_delegate changeText:_textView.text];
}