去掉navigationcontroller返回键文字

//去掉navigationController返回键文字
self.navigationController.navigationBar.topItem.title = @“";

具体可以这样写：

- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
self.navigationController.navigationBar.topItem.title = @"";
}

- (void)viewWillDisappear:(BOOL)animated
{
[super viewWillDisappear:animated];
self.navigationController.navigationBar.topItem.title = @"上一级标题";
}