Custom back button on navigation bar

问题:

In my application there are many UIViewControllers with UINavigationControllers. There must be a "back" button and a "home" UIButton on the UINavigationBar. All of this works fine.

But some of my UIViewControllers have long names, and sometimes there is too small place left for it. I'm trying to replace the original label of the "back" button (it shows the title of the previous view) with a custom "Back", but whatever I tried it didn't work:

// Title didn't change
[self.navigationItem.backBarButtonItem setTitle:@"Back"];

// Action didn't set, no response from button ( button didn't do anything )
[self.navigationItem.leftBarButtonItem
   setAction:self.navigationItem.backBarButtonItem.action];

And I need the "back" button to have a style like in this question: Draw custom Back button on iPhone Navigation Bar

回答1:

Try this

UIBarButtonItem *backBarBtnItem = [[UIBarButtonItem alloc] initWithTitle:@"Back" style:UIBarButtonItemStylePlain target:self action:@selector(popViewController)];
[self.navigationItem setBackBarButtonItem:backBarBtnItem];

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

回答2:

Try the following. It will definitely work:

- (void)viewDidLoad {
    [super viewDidLoad];

    UIImage *buttonImage = [UIImage imageNamed:@"back.png"];
    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    [button setImage:buttonImage forState:UIControlStateNormal];
    button.frame = CGRectMake(0, 0, buttonImage.size.width, buttonImage.size.height);
    [button addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];

    UIBarButtonItem *customBarItem = [[UIBarButtonItem alloc] initWithCustomView:button];
    self.navigationItem.leftBarButtonItem = customBarItem;
    [customBarItem release];
}

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

Make sure you have an button image with the size of a navigation bar back button in your resource folder with name back.png.

Feel free if any other assistance is required.

回答3:

Target: customizing all back button on UINavigationBar to an white icon

Steps: 1. in "didFinishLaunchingWithOptions" method of AppDelete：

UIImage *backBtnIcon = [UIImage imageNamed:@"navBackBtn"];

if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0")) {
    [UINavigationBar appearance].tintColor = [UIColor whiteColor];
    [UINavigationBar appearance].backIndicatorImage = backBtnIcon;
    [UINavigationBar appearance].backIndicatorTransitionMaskImage = backBtnIcon;
}else{

    UIImage *backButtonImage = [backBtnIcon resizableImageWithCapInsets:UIEdgeInsetsMake(0, backBtnIcon.size.width - 1, 0, 0)];
    [[UIBarButtonItem appearance] setBackButtonBackgroundImage:backButtonImage  forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];

    [[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -backButtonImage.size.height*2) forBarMetrics:UIBarMetricsDefault];
}

2.in the "viewDidLoad" method of the common super ViewController class:

 if (SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"7.0")) {
        UIBarButtonItem *backItem = [[UIBarButtonItem alloc] initWithTitle:@""
                                                                     style:UIBarButtonItemStylePlain
                                                                    target:nil
                                                                    action:nil];
        [self.navigationItem setBackBarButtonItem:backItem];
    }else{
        //do nothing
    }

回答4:

If you're doing this all over the place like I am, you're better off implementing Anil's solution as a category:

@interface UIViewController (CustomBackButton)

- (void) setCustomBackButton;
- (void) back;

@end

@implementation UIViewController (CustomBackButton)

- (void) setCustomBackButton
{
    UIImage *buttonImage = [UIImage imageNamed:@"back.png"];
    UIButton *button = [UIButton buttonWithType:UIButtonTypeCustom];
    [button setImage:buttonImage forState:UIControlStateNormal];
    button.frame = CGRectMake(0, 0, buttonImage.size.width, buttonImage.size.height);
    [button addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *customBarItem = [[UIBarButtonItem alloc] initWithCustomView:button];
    self.navigationItem.leftBarButtonItem = customBarItem;
}

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

@end

回答5:

More simply:

UIBarButtonItem *barBtnItem = 
  [[UIBarButtonItem alloc]initWithTitle:@"Indietro"
                                  style:UIBarButtonItemStyleBordered
                                 target:self
                                 action:@selector(pop)];
[barBtnItem setTintColor:[UIColor whiteColor]];
self.navigationItem.leftBarButtonItem = barBtnItem;

回答6:

Suppose you have two controllers - Controller1 and Controller2. Controller2 is pushed from Controller1. So before pushing the Controller2 on the navigationController from Controller1

Controller2 *controller2 = [[[Controller2 alloc]  init]autorelease];
self.navigationItem.hidesBackButton = YES;   

Now, in the viewDidLoad: method of Controller2, add the following snippet

UIBarButtonItem *backBarButtonItem =[[[UIBarButtonItem alloc]initWithTitle:@"Back" style:UIBarButtonItemStyleBordered target:self action:@selector(goBackToAllPets:)]autorelease];
self.navigationItem.leftBarButtonItem = backBarButtonItem;

and in the backButtonClicked method, you can perform the checks you want to.