Android Kotlin ViewPager2 动态 Fragment ExoPlayer 实现上下滑动播放

要实现在Androidx Kotlin中使用ViewPager2和动态Fragment来实现上下滑动播放功能，可以按照以下步骤进行：\n\n1. 首先，确保你的项目中已经添加了ViewPager2和ExoPlayer的依赖。可以在项目的build.gradle文件中添加以下依赖：\n\nkotlin\nimplementation 'androidx.viewpager2:viewpager2:1.0.0'\nimplementation 'com.google.android.exoplayer:exoplayer:2.X.X'\n\n\n2. 创建一个包含ViewPager2的布局文件，例如activity_main.xml。在布局文件中添加ViewPager2组件：\n\nxml\n<androidx.viewpager2.widget.ViewPager2\n android:id="@+id/viewPager"\n android:layout_width="match_parent"\n android:layout_height="match_parent" />\n\n\n3. 创建一个动态Fragment，例如VideoFragment.kt，用于显示视频内容。在该Fragment中，可以使用ExoPlayer来加载和播放视频。\n\nkotlin\nclass VideoFragment : Fragment() {\n private lateinit var playerView: PlayerView\n private lateinit var exoPlayer: SimpleExoPlayer\n\n override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {\n val view = inflater.inflate(R.layout.fragment_video, container, false)\n playerView = view.findViewById(R.id.playerView)\n return view\n }\n\n override fun onViewCreated(view: View, savedInstanceState: Bundle?) {\n super.onViewCreated(view, savedInstanceState)\n exoPlayer = SimpleExoPlayer.Builder(requireContext()).build()\n playerView.player = exoPlayer\n }\n\n override fun onDestroyView() {\n super.onDestroyView()\n exoPlayer.release()\n }\n}\n\n\n4. 创建一个FragmentStateAdapter，用于提供ViewPager2的页面。在MyPagerAdapter.kt中，可以创建一个列表来保存所有的视频Fragment，并实现必要的方法。\n\nkotlin\nclass MyPagerAdapter(fragmentManager: FragmentManager, lifecycle: Lifecycle) : FragmentStateAdapter(fragmentManager, lifecycle) {\n private val fragments = mutableListOf<Fragment>()\n\n fun setFragments(newFragments: List<Fragment>) {\n fragments.clear()\n fragments.addAll(newFragments)\n notifyDataSetChanged()\n }\n\n override fun getItemCount(): Int {\n return fragments.size\n }\n\n override fun createFragment(position: Int): Fragment {\n return fragments[position]\n }\n}\n\n\n5. 在MainActivity中，初始化ViewPager2和Adapter，并设置Adapter到ViewPager2中：\n\nkotlin\nclass MainActivity : AppCompatActivity() {\n private lateinit var viewPager: ViewPager2\n private lateinit var pagerAdapter: MyPagerAdapter\n\n override fun onCreate(savedInstanceState: Bundle?) {\n super.onCreate(savedInstanceState)\n setContentView(R.layout.activity_main)\n\n viewPager = findViewById(R.id.viewPager)\n pagerAdapter = MyPagerAdapter(supportFragmentManager, lifecycle)\n viewPager.adapter = pagerAdapter\n\n val fragments = listOf(VideoFragment(), VideoFragment(), VideoFragment())\n pagerAdapter.setFragments(fragments)\n }\n}\n\n\n现在，你可以在ViewPager2中上下滑动来切换不同的视频播放页面。每个页面都有一个独立的ExoPlayer实例来加载和播放视频。