iPad - Show/Hide UIBarButton

Is there a way开发者_如何学C to hide or show a UIBarButtonItem?

USe this to hide barbutton item.

self.navigationItem.rightBarButtonItem = nil;

Actually, UIBarButtonItem does not respond to .hidden. It is not a subclass of UIButton.

Here is a quick example of how you can switch three buttons a left button a middle button and a right button.

//So, in the proper place

IBOutlet UIToolbar *bottomToolbar;
IBOutlet UIBarButtonItem *leftButton;
IBOutlet UIBarButtonItem *flexerSpace;
IBOutlet UIBarButtonItem *middleButton;
IBOutlet UIBarButtonItem *rightButton;

//Then this in the proper place

@property (retain, nonatomic) IBOutlet UIToolbar *bottomToolbar;
@property (retain, nonatomic) IBOutlet UIBarButtonItem *leftButton;
@property (retain, nonatomic) IBOutlet UIBarButtonItem *flexerSpace;
@property (retain, nonatomic) IBOutlet UIBarButtonItem *middleButton;
@property (retain, nonatomic) IBOutlet UIBarButtonItem *rightButton;

//Then in the proper place

@synthesize bottomToolbar;
@synthesize leftButton;
@synthesize flexerSpace;
@synthesize middleButton;
@synthesize rightButton;

then reload your class in IB or Xcode4 IB in your nib

// then in your

view_switcher/controller methods

-(IBAction)switchToLeft:(id)sender {

NSArray *newButtonArray = [NSArray arrayWithObjects: middleButton, flexerSpace, rightButton, nil];

[bottomToolbar setItems:newButtonArray animated:NO]; //YES or NO either way it
}

-(IBAction)switchToMiddle:(id)sender {

NSArray *newButtonArray = [NSArray arrayWithObjects: leftButton, flexerSpace, rightButton, nil];

[bottomToolbar setItems:newButtonArray animated:NO]; //YES or NO either way it
}

-(IBAction)switchToRight:(id)sender {

NSArray *newButtonArray = [NSArray arrayWithObjects: leftButton, flexerSpace, middleButton, nil];

[bottomToolbar setItems:newButtonArray animated:NO]; //YES or NO either way it
}

then connect the buttons and add your view switching, this should do it ...

Assuming you can fill in some parts

This is my UIBarButtonItem subclass to expose a setHidden method. I use it whenever I have an "optional" button on my bars. It works for textual or image buttons.

class AltoUIBarButtonItem: UIBarButtonItem {

var originalImage : UIImage?
var originalTitle : String?

override func awakeFromNib() {

    originalTitle = self.title
    originalImage = self.image
}

func setHidden(_ hidden: Bool)
{
    if hidden
    {
        if originalImage != nil { self.image = nil}
        if originalTitle != nil { self.title = ""}
        self.isEnabled = false
    }
    else
    {
        if originalImage != nil { self.image = originalImage}
        if originalTitle != nil { self.title = originalTitle}
        self.isEnabled = true
    }
}

func setOriginalTitle(_ originalTitle: String?)
{
    self.originalTitle = originalTitle
}

}