在要修改按钮的UIview的Controller里面。

添加下面代码

- (void)addBackBtn{    UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@"返回" style:UIBarButtonItemStylePlain target:self action:@selector(backtoPre)];    self.navigationItem.leftBarButtonItem = backItem;}- (void)backtoPre{    [self resignFirstResponder];    [self.navigationController popToRootViewControllerAnimated:YES];}