Question

在viewDidload方法中，我声明了一个按钮并设置了RightBarButton ......

    let btnFavourite = UIButton(frame: CGRectMake(0,0,30,30))
    btnFavourite.addTarget(self, action: "btnFavourite:", forControlEvents: .TouchUpInside)
    btnFavourite.setImage(UIImage(named: "star"), forState: .Normal)
    btnFavourite.setImage(UIImage(named: "star_filled"), forState: .Highlighted)
    let rightButton = UIBarButtonItem(customView: btnFavourite)
    self.navigationItem.setRightBarButtonItems([rightButton], animated: true)

如何从图像'star.png'按下按钮然后更改为'star_filled.png'？然后按'star_filled.png'中的按钮到'star.png'？

如何制作两个功能，如

func btnFavourite()
{
    //clicked the favourite button then image change to star_filled.png
}

fun btnUnfavourite()
{
    //clicked the button then the bar button image change to star.png
}

Answer 1

创建方法，根据self.isFavourited

的状态更新Button

var isFavourited = false;//declare this above the viewDidload()

func updateRighBarButton(isFavourite : Bool){
    let btnFavourite = UIButton(frame: CGRectMake(0,0,30,30))
    btnFavourite.addTarget(self, action: "btnFavouriteDidTap", forControlEvents: .TouchUpInside)


    if isFavourite {
         btnFavourite.setImage(UIImage(named: "star_filled"), forState: .Normal)
    }else{
        btnFavourite.setImage(UIImage(named: "star"), forState: .Normal)
    }
    let rightButton = UIBarButtonItem(customView: btnFavourite)
    self.navigationItem.setRightBarButtonItems([rightButton], animated: true)
}



func btnFavouriteDidTap()
{
    //do your stuff
    self.isFavourited = !self.isFavourited;
    if self.isFavourited {
        self.favourite();
    }else{
        self.unfavourite();
    }
    self.updateRighBarButton(self.isFavourited);
}


func favourite()
{
    //do your favourite stuff/logic
}

func unfavourite(){
    //do your unfavourite logic
}

在viewDidload方法中，第一次调用，即

self.updateRighBarButton(self.isFavourited);//first time self.isFavourited will be false

Answer 2

我确信这是一种更优雅的方式，但这对我有用：

在viewDidLoad（）中：

    let share_button = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(shareTapped))
    let fave_button = UIBarButtonItem(image: UIImage(named: "icon-star"), style: .plain, target: self, action: #selector(favorite))
    let faved_button = UIBarButtonItem(image: UIImage(named: "icon-star-filled"), style: .plain, target: self, action: #selector(unfavorite))
    if YOUROBJECT.faved{
        navigationItem.rightBarButtonItems = [share_button, faved_button]
    }
    else{
        navigationItem.rightBarButtonItems = [share_button, fave_button]
    }

然后创建两个#selector函数：

@objc func favorite(){
    let share_button = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(shareTapped))
    let faved_button = UIBarButtonItem(image: UIImage(named: "icon-star-filled"), style: .plain, target: self, action: #selector(unfavorite))
    navigationItem.rightBarButtonItems = [share_button, faved_button]
    YOUROBJECT.faved = true
}
@objc func unfavorite(){
    let share_button = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(shareTapped))
    let fave_button = UIBarButtonItem(image: UIImage(named: "icon-star"), style: .plain, target: self, action: #selector(favorite))
    navigationItem.rightBarButtonItems = [share_button, fave_button]
    YOUROBJECT.faved = false
}

按下iOS swift后更改UIBarButtonItem图标

2 个答案: