How do I show/hide a UIBarButtonItem?

Question

I created a toolbar in IB with several buttons. I would like to be able to hide/show one of the buttons depending on the state of the data in the main window.

Answer 1

It is possible to hide a button in place without changing its width or removing it from the bar. If you set the style to plain, remove the title, and disable the button, it will disappear. To restore it, just reverse your changes.

-(void)toggleBarButton:(bool)show
{
    if (show) {
        btn.style = UIBarButtonItemStyleBordered;
        btn.enabled = true;
        btn.title = @"MyTitle";
    } else {
        btn.style = UIBarButtonItemStylePlain;
        btn.enabled = false;
        btn.title = nil;
    }
}

Answer 2

Below is my solution though i was looking it for Navigation Bar.

navBar.topItem.rightBarButtonItem = nil;

Here "navBar" is a IBOutlet to the NavigationBar in the view in XIB Here i wanted to hide the button or show it based on some condition. So i m testing for the condition in "If" and if true i am setting the button to nil in viewDidLoad method of the target view.

This may not be relevant to your problem exactly but something similar incase if you want to hide buttons on NavigationBar

Answer 3

I'll add my solution here as I couldn't find it mentioned here yet. I have a dynamic button whose image depends on the state of one control. The most simple solution for me was to set the image to nil if the control was not present. The image was updated each time the control updated and thus, this was optimal for me. Just to be sure I also set the enabled to NO.

Setting the width to a minimal value did not work on iOS 7.

Answer 4

I discovered another wrinkle in the tintColor and isEnabled approach suggested by Max and others - when VoiceOver is enabled for accessibility and the button is logically hidden, the accessibility cursor will still focus on the bar button, and state that it is "dimmed" (i.e. because isEnabled is set to false). The approach in the accepted answer doesn't suffer from this side-effect, but another work around I found was to set isAccessibilityElement to false when "hiding" the button:

deleteButton.tintColor = UIColor.clear
deleteButton.isEnabled = false
deleteButton.isAccessibilityElement = false

And then setting isAccessibilityElement back to true when "showing" the button:

deleteButton.tintColor = UIColor.blue
deleteButton.isEnabled = true
deleteButton.isAccessibilityElement = true

Having the bar button item still take up space was not an issue in my case, since we were hiding/showing the left-most of right bar button items.

Answer 5

Complementing Eli Burke`s response, if your UIBarButtonItemhas a background image instead of a title, you can use the code:

-(void)toggleLogoutButton:(bool)show{
    if (show) {
        self.tabButton.style = UIBarButtonItemStyleBordered;
        self.tabButton.enabled = true;
        UIImage* imageMap = [UIImage imageNamed:@"btn_img.png"];
        [((UIButton *)[self.tabButton customView]) setBackgroundImage:imageMap forState:UIControlStateNormal];
    } else {
        self.tabButton.style = UIBarButtonItemStylePlain;
        self.tabButton.enabled = false;
        [((UIButton *)[self.tabButton customView]) setBackgroundImage:nil forState:UIControlStateNormal];
    }
}

Answer 6

In IB if you leave the button's title blank it will not appear (never initialized?). I do this often during development during UI updates if I want a bar button item to temp disappear for a build without deleting it and trashing all its outlet references.

This does not have the same effect during runtime, setting the button's title to nil will not cause it the whole button to disappear. Sorry doesn't really answer your question, but may be useful to some.

Edit: This trick only works if the button's style is set to plain