ios - 有没有办法在 Swift 中立即更改 UIBarButtonItem？

Question

我在顶部导航栏中添加了一个“最喜欢的图标”(一颗心):

var faveMeItem = UIBarButtonItem (title: dua.isFavorite() ? "❤️" : "💔", style: .Plain, target: self, action: "toggleFav")

有没有办法确保它在被点击后立即改变(变成 splinter 的心)？

我必须返回 tableView 并返回详细信息，然后我会看到更新的图标。点击它会执行逻辑，但心脏不会更新。这些是我的 Dua 类中的函数。

func removeFromFavorites() {
    //retrieve all favorites
    let favoriteDuaIds = NSUserDefaults.standardUserDefaults().objectForKey(Dua.favoriteDuasKey) as! [Int]?
    if let favoriteDuaIds = favoriteDuaIds {
        //iterate through all Duas and comapre their IDs
        let newFavoriteDuaIds = favoriteDuaIds.filter { favoriteDuaId in
            return favoriteDuaId != duaId
        }
        NSUserDefaults.standardUserDefaults().setObject(newFavoriteDuaIds, forKey: Dua.favoriteDuasKey)
    }
}

func isFavorite() -> Bool {
    //retrieve all favorites
    let favoriteDuaIds = NSUserDefaults.standardUserDefaults().objectForKey(Dua.favoriteDuasKey) as! [Int]?
    if let favoriteDuaIds = favoriteDuaIds {
        //iterate through all Duas and comapre their IDs
        for favoriteDuaId in favoriteDuaIds {
            print (favoriteDuaId)
            if favoriteDuaId == duaId {
                return true
            }
        }
    }
    return false
}

func toggleFavorite() {
    if isFavorite() {
        removeFromFavorites()
    } else {
        addToFavorites()
    }
}

class func favorites() -> [Dua] {
    let favoriteDuaIds = NSUserDefaults.standardUserDefaults().objectForKey(favoriteDuasKey) as! [Int]?
    if let favoriteDuaIds = favoriteDuaIds {
        return DuasDataSource.duas.filter { dua in
            return favoriteDuaIds.contains(dua.duaId)
        }
    } else {
        return []
    }
  }

}

Answer 1

func toggleFavorite() {
    if isFavorite() {
        removeFromFavorites()
    } else {
        addToFavorites()
    }
faveMeItem.title = dua.isFavorite() ? "❤️" : "💔" //Add this
}