How do I hide/show the right button in the Navigat

问题:

I need to hide the right button in the Navigation Bar, then unhide it after the user selects some options.

Unfortunately, the following doesn't work:

NO GOOD: self.navigationItem.rightBarButtonItem.hidden = YES;  // FOO CODE

Is there a way?

回答1:

Hide the button by setting the reference to nil, however if you want to restore it later, you'll need to hang onto a copy of it so you can reassign it.

UIBarButtonItem *oldButton = self.navigationItem.rightBarButtonItem;
[oldButton retain];
self.navigationItem.rightBarButtonItem = nil;

//... later
self.navigationItem.rightBarButtonItem = oldButton;
[oldButton release];

Personally, in my apps I make my nav buttons into @properties, so that I can trash & recreate them at will, so something like:

//mycontroller.h
UIBarButtonItem *rightNavButton;
@property (nonatomic, retain) UIBarButtonItem *rightNavButton;

//mycontroller.m
@synthesize rightNavButton;
- (UIBarButtonItem *)rightNavButton {
    if (!rightNavButton) {
        rightNavButton = [[UIBarButtonItem alloc] init];
        //configure the button here
    }
    return rightNavButton;
}

//later, in your code to show/hide the button:
self.navigationItem.rightBarButtonItem = self.rightNavButton;

回答2:

For Swift 3

if let button = self.navigationItem.rightBarButtonItem {
                    button.isEnabled = false
                    button.tintColor = UIColor.clear
                }`

回答3:

Set reference to nil:

current_controller_in_navcontroller.navigationItem.rightBarButtonItem =  nil;

Also be sure to call this in the controller currently shown by the navController, not for the navController itself.

回答4:

Show:

[self.navigationItem.rightBarButtonItem.customView setAlpha:1.0];

Hide:

[self.navigationItem.rightBarButtonItem.customView setAlpha:0.0];

You can even animate its showing/hiding

[UIView animateWithDuration:0.2 animations:^{
        [self.navigationItem.rightBarButtonItem.customView setAlpha:1.0];

    }];

回答5:

Here's Matt's solution updated for Storyboards & ARC. Remember, IBOutlets are __weak by default, so you need to change that to strong for it not to be released too early.

@interface MAGTableViewController () <UITextFieldDelegate>

@property (strong, nonatomic) IBOutlet UIBarButtonItem *rightBarButton;

@end

@implementation MAGTableViewController

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self.navigationItem setRightBarButtonItem:nil];
}

- (IBAction)rightBarButtonItemTapped:(id)sender
{
    [self.view endEditing:YES];
}

- (void)textFieldDidBeginEditing:(UITextField *)textField
{
    [self.navigationItem setRightBarButtonItem:self.rightBarButton];
}

- (void)textFieldDidEndEditing:(UITextField *)textField
{
    [self.navigationItem setRightBarButtonItem:nil];
}

@end

回答6:

SWIFT 2.2

In swift 2.2 self.navigationItem does not work. Instead create an outlet of the NavigationItem (I named it below "nav") and use it.

Also the following suggestion did not work for me using Xcode 7.3 and swift 2.2

 nav.leftBarButtonItem?.customView?.hidden = true

So I used the idea of @Matt J above as follows (I have 2 items on the left):

1. Create outlets for the items in the navigation bar and variables to store them

   @IBOutlet weak var settingItem: UIBarButtonItem!
   @IBOutlet weak var logoItem: UIBarButtonItem!
   
   var sav_settingItem: UIBarButtonItem = UIBarButtonItem()
   var sav_logoItem: UIBarButtonItem = UIBarButtonItem()
   

2. Save the items in viewDidLoad()

   sav_settingItem = nav.leftBarButtonItems![0]
   sav_logoItem = nav.leftBarButtonItems![1]
   

3. To HIDE set them to nil

   nav.leftBarButtonItem = nil
   nav.leftBarButtonItem = nil
   

4. To SHOW them

   if (nav.leftBarButtonItem == nil) {
       nav.leftBarButtonItem = sav_settingItem
       nav.leftBarButtonItems?.append(sav_logoItem)
       return
   }
   

回答7:

Credit has to go to learner for this answer which the answer is from this question:

hide and show left navigation bar button on demand in iOS-7

This is the answer, which is far more simple.

//hide and reveal bar buttons
-(void) hideAndDisableLeftNavigationItem
{
    [self.navigationItem.leftBarButtonItem setTintColor:[UIColor clearColor]];
    [self.navigationItem.leftBarButtonItem setEnabled:NO];
}

-(void) showAndEnableLeftNavigationItem
{
    [self.navigationItem.leftBarButtonItem setTintColor:[UIColor blueColor]];
    [self.navigationItem.leftBarButtonItem setEnabled:YES];
}

Then you just reference the method where you require it like within an (IBAction) like so:

[self hideAndDisableLeftNavigationItem];//[self showAndEnableLeftNavigationItem]; to show again

I tried all other methods and none worked, even referencing my button as a @property (...) UIBarButtonItem.... and nothing worked until I found this.

回答8:

Show:

[self.navigationItem.rightBarButtonItem.customView setHidden:NO];

Hide:

[self.navigationItem.rightBarButtonItem.customView setHidden:YES];

回答9:

Swift 2:

Trick!

Hide:

if let btn = self.tabBarController!.navigationItem.rightBarButtonItem {
        btn.enabled = false
        btn.title = ""
}

Show:

if let btn = self.tabBarController!.navigationItem.rightBarButtonItem {
        btn.enabled = true
        btn.title = "ButtonName"
}

回答10:

My solution:

self.navigationItem.rightBarButtonItem.customView.hidden=NO;

回答11:

Show:

//set navigationItem tint color white
self.navigationItem.rightBarButtonItem.tintColor = [UIColor whiteColor];

Hide:

//set navigationItem tint clear white
self.navigationItem.rightBarButtonItem.tintColor = [UIColor clearColor];

回答12:

1. Assume you can reference the specific bar button as variable xxxButton

(please open Assistant Editor, Control+Drag xxx button to YourViewController class as outlet "xxxButton").

or you can use something like let xxxButton = navigationBar.buttons[1]

2. Hide xxxButton.customView = UIView() or navigationItem.rightBarButtonItems?.remove(at: (navigationItem.rightBarButtonItems?.index(of:xxxButton)!)!)

3. Show xxxButton.customView = nil or navigationItem.rightBarButtonItems?.insert(newElement: xxxButton, at:SOME_INDEX)

Hope helpful.

回答13:

To hide:

if let topItem = self.navigationController?.navigationBar.topItem {
    topItem.rightBarButtonItem = nil
}

回答14:

In swift 4 I has a trick to show / hide right or left button:

Step 1: Create a IBOutlet button in view controller:

@IBOutlet var navigationItemButton: UIBarButtonItem!

Step 2: Create Hide button function:

func hideNavigationButton() {
    navigationItemButton.isEnabled = false
    navigationItemButton.tintColor = UIColor.clear
}

Step 3: Create Show button function:

func showNavigationButton() {
    navigationItemButton.isEnabled = true
    navigationItemButton.tintColor = UIColor.white
}

Step 4: Just call the functions that you want, use hideNavigationButton() to hide, and showNavigationButton() to show the button.

Regards!

回答15:

Set the the title to empty first and after swlwction just set again.