带有自定义后退按钮的UINavigationController子类

Question

I know I can set custom back button from the view controller itself, something like:

- (void)setBackButton
{
    UINavigationBar* navBar = self.navigationController.navigationBar;
    UIButton* backButton = [navBar backButtonWith:[UIImage imageNamed:@"navigationBarBackButton.png"] 
                                        highlight:nil 
                                     leftCapWidth:14.0];

    [backButton addTarget:self action:@selector(backButtonTapped:) forControlEvents:UIControlEventTouchUpInside];

    self.navigationItem.leftBarButtonItem = [[[UIBarButtonItem alloc] initWithCustomView:backButton] autorelease];
}

- (void)backButtonTapped:(id)sender
{
    [self.navigationController popViewControllerAnimated:YES];
}  

The problem is that I need to do it for all my view controllers...
One solution is to put this code in some BasicViewController and all my view controllers will subclass it.

But my question is can I subclass the UINavigationCotroller itself and set it's nab bar left button to this custom button?

Answer 1

The right way to do this is using UIAppearance

It provides methods on UIBarButtonItem such as

- (void)setBackButtonBackgroundImage:(UIImage *)backgroundImage forState:(UIControlState)state barMetrics:(UIBarMetrics)barMetrics

and

- (void)setBackButtonBackgroundVerticalPositionAdjustment:(CGFloat)adjustment forBarMetrics:(UIBarMetrics)barMetrics

Answer 2

不。最好有一个自定义的UIViewController来处理这种行为。