iPad - 显示/隐藏 UIBarButton

Question

有没有办法隐藏或显示 UIBarButtonItem？

Answer 1

使用它来隐藏栏按钮项目。

self.navigationItem.rightBarButtonItem = nil;

Answer 2

实际上，UIBarButtonItem 并不响应 .hidden。它不是 UIButton 的子类。

以下是如何切换三个按钮（左按钮、中按钮和右按钮）的快速示例。

//所以，在正确的位置

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

//然后在正确的位置

@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;

//然后在正确的位置

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

然后在笔尖中的 IB 或 Xcode4 IB 中重新加载您的类

// 然后在您的

view_switcher/controller 方法

-(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
}

中然后连接按钮并添加你的视图切换，这应该可以......

假设你可以填写一些部分

Answer 3

这是我的 UIBarButtonItem 子类，用于公开 setHidden 方法。每当我的栏上有“可选”按钮时我就会使用它。
它适用于文本或图像按钮。

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
}

}