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Ios 如何检查核心数据是否为空?_Ios_Swift_Core Data - Fatal编程技术网

Ios 如何检查核心数据是否为空?

Ios 如何检查核心数据是否为空?,ios,swift,core-data,Ios,Swift,Core Data,我正在使用核心数据填充集合视图。现在我想检查它是否为空。如果它是空的,我想做额外的事情。我怎样才能做到这一点 if myJokes.isEmpty == true { noFavorites.isHidden = false } 我尝试过这样检查,但不起作用: class ViewController2: UIViewController, UICollectionViewDelegateFlowLayout, UICollectionViewDelegate, UICollect

我正在使用核心数据填充集合视图。现在我想检查它是否为空。如果它是空的,我想做额外的事情。我怎样才能做到这一点

if myJokes.isEmpty == true {
    noFavorites.isHidden = false
  }
我尝试过这样检查,但不起作用:

class ViewController2: UIViewController, UICollectionViewDelegateFlowLayout, UICollectionViewDelegate, UICollectionViewDataSource {

    var myJokes : [MyJokes] = []

    override func viewDidLoad() {
        super.viewDidLoad()

        getData()
        myCollectionView.reloadData()
    }

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return myJokes.count
    }

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = myCollectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! CollectionViewCell2
        if myJokes.isEmpty == true {
            noFavorites.isHidden = false
        }
        cell.backView.layer.cornerRadius = 10
        let task = myJokes[indexPath.row]
        cell.textLabel.text = task.favoriteJokes!
        return cell
    }

    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: myCollectionView.frame.width, height: 58)
    }

    func getData() {
        let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
        do {
        myJokes = try context.fetch(MyJokes.fetchRequest())
        } catch {}
    }

    @IBAction func menuBtnPressed(_ sender: Any) {
        if menuShowing {
            menuConstraint.constant = -171
            UIView.animate(withDuration: 0.4, animations: {
                self.view.layoutIfNeeded()
            })
}

在我的笑话里,你得到了什么样的数据?像字典一样,数组etcAn字符串数组ID您可以尝试
mycrooks.count
?是的,不起作用either@Volkan然后使用like if myJokes.count>0{//here data}或者{//no data}