如何在 Android 中构建视频播放器的完整指南

在移动应用中，视频播放器是非常重要的一部分。在Android平台上，我们可以通过自定义视频播放器来实现更多自定义功能。本指南将为您提供在Android上构建视频播放器的完整指南。

准备工作

1. 在Android Studio上创建新项目。

2. 添加以下依赖项：

   dependencies {
       implementation 'com.google.android.exoplayer:exoplayer:2.12.1'
   }
   

3. 编写布局文件

   <?xml version="1.0" encoding="utf-8"?>
   <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
       android:layout_width="match_parent"
       android:layout_height="match_parent">
   
       <com.google.android.exoplayer2.ui.PlayerView
           android:id="@id/player_view"
           android:layout_width="match_parent"
           android:layout_height="match_parent"
           android:fitsSystemWindows="true"
           android:keepScreenOn="true"
           android:visibility="visible"
           app:resize_mode="fill"
           app:surface_type="texture_view" />
   
   </RelativeLayout>
   

加载视频

1. 创建一个播放器实例：

   private var player: SimpleExoPlayer? = null
   
   private fun initializePlayer() {
       if (player == null) {
           player = SimpleExoPlayer.Builder(context).build()
           playerView.player = player
       }
   }
   

2. 创建数据源：

   private fun buildMediaSource(uri: Uri): MediaSource {
       return ExtractorMediaSource.Factory(
           DefaultDataSourceFactory(context, "user-agent")
       ).createMediaSource(uri)
   }
   

3. 加载视频：

   private fun initializePlayer() {
       if (player == null) {
           player = SimpleExoPlayer.Builder(context).build()
           playerView.player = player
           val mediaSource = buildMediaSource(Uri.parse("https://www.example.com/video.mp4"))
           player?.setMediaSource(mediaSource)
           player?.prepare()
       }
   }
   

自定义播放器控件

1. 创建一个布局文件：

   <?xml version="1.0" encoding="utf-8"?>
   <com.google.android.exoplayer2.ui.PlayerView xmlns:android="http://schemas.android.com/apk/res/android"
       xmlns:app="http://schemas.android.com/apk/res-auto"
       android:id="@id/player_view"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:keepScreenOn="true"
       app:controller_layout_id="@layout/custom_player_control_view" />
   

2. 创建一个自定义控件：

   class CustomPlayerControlView : FrameLayout, PlayerControlView {
   
       private val binding = CustomPlayerControlBinding.inflate(LayoutInflater.from(context), this, true)
   
       override fun show() {
           isVisible = true
       }
   
       override fun hide() {
           isVisible = false
       }
   
       override fun setPlayer(player: Player?) {}
   
       override fun setVisibilityListener(visibilityListener: PlayerControlView.VisibilityListener?) {}
   
       override fun setControlDispatcher(controlDispatcher: ControlDispatcher?) {}
   
       override fun setRewindIncrementMs(rewindMs: Int) {}
   
       override fun setFastForwardIncrementMs(fastForwardMs: Int) {}
   
       override fun setRepeatToggleModes(repeatToggleModes: Int) {}
   
       override fun getRepeatToggleModes(): Int = REPEAT_TOGGLE_MODE_NONE
   
       override fun setShowMultiWindowTimeBar(show: Boolean) {}
   
       override fun setExtraAdGroupMarkers(extraAdGroupTimesMs: LongArray?, extraPlayedAdGroups: BooleanArray?, adGroupCount: Int) {}
   
       override fun setAspectRatioListener(listener: AspectRatioFrameLayout.AspectRatioListener?) {}
   
       override fun setUseArtwork(useArtwork: Boolean) {}
   
       override fun setErrorMessageProvider(errorMessageProvider: ErrorMessageProvider<in ExoPlaybackException>?) {}
   
       override fun setCustomErrorMessage(customErrorMessage: CharSequence?) {}
   
       override fun setAdGroupTimesMs(adGroupTimesMs: LongArray?, playedAdGroups: BooleanArray?, adGroupCount: Int) {}
   
       override fun setMaxSeekToPreviousPositionMs(maxSeekToPreviousPositionMs: Int) {}
   
       override fun setVisibilityListener(visibilityListener: VisibilityListener?) {}
   
       override fun setPlayWhenReady(playWhenReady: Boolean) {}
   
       override fun setRepeatToggleModes(@RepeatMode repeatToggleModes: Int) {}
   
       override fun setShowShuffleButton(showShuffleButton: Boolean) {}
   
       override fun setPlayer(player: Player) {}
   
       override fun setKeepContentOnPlayerReset(keepContentOnPlayerReset: Boolean) {}
   
       override fun setIsTouching(isTouching: Boolean) {}
   
       override fun setControlDispatcher(controlDispatcher: ControlDispatcher) {}
   
       override fun setFastForwardIncrementMs(fastForwardMs: Int) {}
   
       override fun setShowNextButton(showNextButton: Boolean) {}
   
       override fun setShowPreviousButton(showPreviousButton: Boolean) {}
   
       override fun setRewindIncrementMs(rewindMs: Int) {}
   
       override fun setShowFastForwardButton(showFastForwardButton: Boolean) {}
   
       override fun setExtraAdGroupMarkers(adGroupTimesMs: LongArray?, playedAdGroups: BooleanArray?, adGroupCount: Int, extraAdGroupTimesMs: LongArray?, extraPlayedAdGroups: BooleanArray?, extraAdGroupCount: Int) {}
   
       override fun setShowRewindButton(showRewindButton: Boolean) {}
   
       override fun setShowMultiWindowTimeBar(showMultiWindowTimeBar: Boolean) {}
   
       override fun setAspectRatioListener(listener: AspectRatioListener) {}
   
       override fun setTimeline(timeline: Timeline?) {}
   
       override fun setCustomFastForwardIncrementMs(customFastForwardMs: Long) {}
   
       override fun setCustomRewindIncrementMs(customRewindMs: Long) {}
   
       override fun setUseController(useController: Boolean) {}
   
   }
   

   在show()和hide()方法中，您可以添加控制视图的逻辑。在布局文件中，您可以设置app:controller_layout_id属性为您创建的自定义控件布局。

集成广告

要在Android中集成视频广告，您可以使用IMA插件。下面是集成视频广告的步骤：

1. 添加以下依赖项：

   implementation 'com.google.ads.interactivemedia.v3:interactivemedia:4.1.0'
   implementation 'com.google.android.exoplayer:extension-ima:2.12.1'
   

2. 创建IMA广告加载器：

   private fun createImaAdsLoader(context: Context, adTagUrl: String): AdsLoader {
       return ImaAdsLoader.Builder(context)
           .setAdEventListener(ImaEventListener())
           .setAdUiViewGroup(adViewGroup)
           .setAdDisplayContainer(adDisplayContainer)
           .setAdErrorListener(ImaErrorListener())
           .setAdTagProvider { adTagUrl }
           .build()
   }
   

3. 加载广告：

   private fun initializePlayer() {
       if (player == null) {
           player = SimpleExoPlayer.Builder(context)
               .setMediaSourceFactory(AdsMediaSourceFactory(context, createImaAdsLoader(context, "https://pubads.g.doubleclick.net/gampad/ads?sz=640x480&" +
                       "iu=/124319096/external/single_ad_samples&ciu_szs=300x250&impl=s&gdfp_req=1&env=vp&output=vast&" +
                       "unviewed_position_start=1&cust_params=deployment%3Ddevsite%26sample_ct%3Dlinear&correlator="))
               .build()
           playerView.player = player
           val mediaSource = buildMediaSource(Uri.parse("https://www.example.com/video.mp4"))
           player?.setMediaSource(mediaSource)
           player?.prepare()
       }
   }
   

   在createImaAdsLoader()方法中，您需要更改setAdUiViewGroup()和setAdDisplayContainer()方法的参数。在initializePlayer()方法中，您需要更改广告标记URL。

结论

通过本指南，您现在已经知道如何在Android中构建自定义视频播放器，自定义控件以及集成广告，并可以为用户提供更好的体验。有了这些知识，您将能够创建更具有创意和自定义性质的视频播放器。