Question

我在KVO上建立了具有循环播放功能的视频片段的自动播放序列。但是，除了自动播放外，我还想使用NSButton来推进所有剪辑。因此，如果在自动播放序列时按Next Video按钮，此操作会将我带到队列中的下一个剪辑。但这不是正确的方法。

问题是：当队列结束时，队列中的所有剪辑都没有循环。仅在第一个剪辑有一个循环（如果我按了Next Video按钮10次– 仅第一个剪辑循环了10次），之后所有剪辑都可以正常自动播放。

问题：如何（在前进时）使用NSButton循环浏览所有视频？

这是我的代码：

import Cocoa
import AVFoundation
import AVKit

class ViewController: NSViewController {

    @IBOutlet weak var avPlayerView: AVPlayerView!
    @IBOutlet weak var nextVideoButton: NSButton!
    @objc private let player = AVQueuePlayer()
    let clips = ["One", "Two", "Three", "Four"]
    private var token: NSKeyValueObservation?

    override func viewDidAppear() {
        super.viewDidAppear()
        addAllVideosToPlayer()
    }

    func addAllVideosToPlayer() {
        avPlayerView.player = player
        for clip in clips {
            let urlPath = Bundle.main.path(forResource: clip, ofType: "mov")!
            let url = URL(fileURLWithPath: urlPath)
            let playerItem = AVPlayerItem(url: url)
            player.insert(playerItem, after: player.items().last)

            token = player.observe(\.currentItem) { [weak self] player, _ in
                if self!.player.items().count == 1 { self?.addAllVideosToPlayer() }
            }
            player.play()
            avPlayerView.controlsStyle = .none
        }
    }

    @IBAction func nextVideo(_ sender: Any) {
        var number: Int = 0
        let clip = clips[number]

        let urlPath = Bundle.main.path(forResource: clip, ofType: "mov")!
        let url = URL(fileURLWithPath: urlPath)
        let playerItem = AVPlayerItem(url: url)
        player.insert(playerItem, after: player.items().last)

        player.advanceToNextItem()
        number += 1

        if number >= clips.count {
            number = 0
            player.advanceToNextItem()
            number += 1
        }
    }
}

这是我的ViewController：

Answer 1

您始终在此处访问第一个视频：

var quarters = [{
    beginning: 11,
    end: 1
  },
  {
    beginning: 2,
    end: 4
  },
  {
    beginning: 5,
    end: 7
  },
  {
    beginning: 8,
    end: 10
  }
];

function findQuarter(month) {
  // Sort your quarters
  quarters = quarters.sort(function(a, b) {
    return a.beginning < b.beginning;
  });

  return quarters.find(function(q) {
    if (q.beginning <= q.end)
      return q.beginning <= month && month <= q.end;
    if (q.beginning > q.end)
      return q.beginning <= month && month <= 12 ||
        1 <= month && month <= q.end;
  });
}

for (var i = 1; i <= 12; i++) {
  console.log("For month " + i + " quarter: " + JSON.stringify(findQuarter(i)));
}

数字始终为零。将其保留为该类的成员，并在需要时进行更新。

Answer 2

这是我的问题的解决方案（感谢@giorashc）：

class ViewController: NSViewController {

    var number: Int = 0                                         // class member

    .........................................
    .........................................

    @IBAction func nextVideo(_ sender: Any) {

        let clip = clips[number % 4]                            // modulus of 4   

        let urlPath = Bundle.main.path(forResource: clip, ofType: "mov")!
        let url = URL(fileURLWithPath: urlPath)
        let playerItem = AVPlayerItem(url: url)
        player.insert(playerItem, after: player.items().last)
        player.advanceToNextItem()
        number += 1
    }
}

“ advanceToNextItem（）”不允许循环浏览所有视频

2 个答案: