Iphone 自定义后退按钮图像在导航栏上不起作用

我创建了一个自定义导航返回按钮。但当我添加这段代码时，我的背部动画不起作用，它会随着动画一起返回。为什么？我想这取决于我的@selector操作

- (void)viewDidLoad {


    UIButton *button =  [UIButton buttonWithType:UIButtonTypeCustom];
    [button setImage:[UIImage imageNamed:@"goback.png"] forState:UIControlStateNormal];
    [button addTarget:self action:@selector(//HERE ! i don't know put what thing !) forControlEvents:UIControlEventTouchUpInside];
    [button setFrame:CGRectMake(0, 0, 32, 32)];
    self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithCustomView:button];
}

---

好的，我创建了一个函数，工作正常：D:

-(void)pushNav {
[self.navigationController popViewControllerAnimated:YES];  
}

---

只是一张纸条。。。无需编写self.navigationItem.leftBarButtonItem=[[UIBarButtonItem alloc]initWithCustomView:button]；您可以直接编写self.navigationItem.leftBarButtonItem=buttonMethod可能应该称为popNav以适应功能