如果它是同一个类Swift，如何将数据传递给前一个视图控制器

Question

我有一个表格视图控制器，当我单击 navigationBarItem 中的按钮时，我打开了相同的视图控制器，但设置略有不同，具体取决于标志。通过关闭此视图控制器，我想将值传递给前一个并用新数据重新加载其数据，我该怎么做？委托在这里无济于事，因为它是同一个类。

class LibraryViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
...
var isContentFromPlaylist: Bool = false
...
//I open the same VC
@IBAction func addTracksButtonPressed(_ sender: Any) {
        let storyboard = UIStoryboard(name: "LibraryViewController", bundle: nil)
        let vc = storyboard.instantiateViewController(identifier: "Library") as! LibraryViewController
        ...
        navigationController?.showDetailViewController(vc, sender: nil)
    }
...
 @objc private func doneButtonPressed() {
        ...
        //Here I want to change value isContentFromPlaylist to true in previous VC when this VC will close

        dismiss(animated: true, completion: nil)
    }
}

Answer 1

您可以使用这种方法。向类添加属性

class LibraryViewController {
    //...
    var creator: LibraryViewController?
    //...
}

然后，在控制器实例化后设置该属性...

@IBAction func addTracksButtonPressed(_ sender: Any) {
    let storyboard = UIStoryboard(name: "LibraryViewController", bundle: nil)
    let vc = storyboard.instantiateViewController(identifier: "Library") as! LibraryViewController
    //...
    vc.creator = self // Here it is
    //...
    navigationController?.showDetailViewController(vc, sender: nil)
}

并以您喜欢的方式使用它：

@objc private func doneButtonPressed() {
        ...
        //Here I want to change value isContentFromPlaylist to true in previous VC when this VC will close
        creator?.isContentFromPlaylist = .........
            
        dismiss(animated: true, completion: nil)
    }
}

附：要重新加载数据，请使用 UI 线程：

DispatchQueue.main.async{
    creator?.tableView.reloadData()
}