如何理解与Android中的iOS关闭/回调等效

问题描述

我来自iOS开发人员，想知道我是否在Android中正确实现了闭包。

这是我要复制的iOS代码：

func playVideoAtCell(_ cellNumber: Int) {

    if (currentlyPlayingVideo) {return}

    getDownloadURL(cellNumber) { (url) in
        self.avPlayer = AVPlayer(url: url)
        self.avPlayerViewController.player = self.avPlayer
        self.avPlayerViewController.showsPlaybackControls = false

        NotificationCenter.default.addObserver(self, selector: #selector(self.videoItemFinished(_:)), name: NSNotification.Name.AVPlayerItemDidPlayToEndTime, object: self.avPlayer?.currentItem)

        self.present(self.avPlayerViewController, animated: true) { () -> Void in
            self.avPlayerViewController.player?.play()
        }
    }
}


func getDownloadURL (_ cellNumber: Int, callback: @escaping (URL) -> ()) {
    let mediaID = mediaIntroQueueList[cellNumber]["mediaID"] as? String

    Constants.storageMediaRef.child("\(mediaID!)").downloadURL(completion: { (URL, error) in
        if error != nil {
            self.showVideoErrorAlert()
            if let indexPath = self.tableView.indexPathForSelectedRow {
                self.tableView.deselectRow(at: indexPath, animated: true)
            }

        }
        if let downloadURL = URL {
            callback (downloadURL)
        }
    })
}

我用Java创建了一个接口：

public interface MeetActivityInterface {
    public void downloadURLCompleted(Uri url);
}

这是我在活动中的Java代码：

private void playVideoAtCell(int cellNumber){

    getDownloadURL(cellNumber, new MeetActivityInterface() {
        @Override
        public void downloadURLCompleted(Uri url) {
            // play video with url
        }
    });
}

private void getDownloadURL(int cellNumber, final MeetActivityInterface completion) {
    String mediaID = mediaIntroQueueList.get(cellNumber).getMediaID();

    // firebase storage
    Constants.storageMediaRef.child(mediaID).getDownloadUrl().addOnSuccessListener(new OnSuccessListener<Uri>()
    {
        @Override
        public void onSuccess(Uri downloadURL)
        {
            completion.downloadURLCompleted(downloadURL);
        }
    });
}

有人可以告诉我我走的路是否正确吗？ 我不确定自己在做什么。 谢谢。