Flutter中使用better_player出现MediaSource相关空指针异常求助

异常信息 #

E/MethodChannel#better_player_channel: Failed to handle method call
java.lang.NullPointerException: MediaSource.Factory#setDrmSessionManagerProvider no longer handles null by instantiating a new DefaultDrmSessionManagerProvider. Explicitly construct and pass an instance in order to retain the old behavior.
at com.google.android.exoplayer2.util.Assertions.checkNotNull(Assertions.java:174)
at com.google.android.exoplayer2.source.ProgressiveMediaSource$Factory.setDrmSessionManagerProvider(ProgressiveMediaSource.java:186)
at com.jhomlala.better_player.BetterPlayer.buildMediaSource(BetterPlayer.kt:430)
at com.jhomlala.better_player.BetterPlayer.setDataSource(BetterPlayer.kt:196)
at com.jhomlala.better_player.BetterPlayerPlugin.setDataSource(BetterPlayerPlugin.kt:277)
at com.jhomlala.better_player.BetterPlayerPlugin.onMethodCall(BetterPlayerPlugin.kt:151)
at com.jhomlala.better_player.BetterPlayerPlugin.onMethodCall(BetterPlayerPlugin.kt:138)
at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:262)
at io.flutter.embedding.engine.dart.DartMessenger.invokeHandler(DartMessenger.java:295)
at io.flutter.embedding.engine.dart.DartMessenger.lambda$dispatchMessageToQueue$0$io-flutter-embedding-engine-dart-DartMessenger(DartMessenger.java:319)
at io.flutter.embedding.engine.dart.DartMessenger$$ExternalSyntheticLambda0.run(Unknown Source:12)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:246)
at android.app.ActivityThread.main(ActivityThread.java:8633)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)
E/flutter: [ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: PlatformException(error, MediaSource.Factory#setDrmSessionManagerProvider no longer handles null by instantiating a new DefaultDrmSessionManagerProvider. Explicitly construct and pass an instance in order to retain the old behavior., null, java.lang.NullPointerException: MediaSource.Factory#setDrmSessionManagerProvider no longer handles null by instantiating a new DefaultDrmSessionManagerProvider. Explicitly construct and pass an instance in order to retain the old behavior.
at com.google.android.exoplayer2.util.Assertions.checkNotNull(Assertions.java:174)
at com.google.android.exoplayer2.source.ProgressiveMediaSource$Factory.setDrmSessionManagerProvider(ProgressiveMediaSource.java:186)
at com.jhomlala.better_player.BetterPlayer.buildMediaSource(BetterPlayer.kt:430)
at com.jhomlala.better_player.BetterPlayer.setDataSource(BetterPlayer.kt:196)
at com.jhomlala.better_player.BetterPlayerPlugin.setDataSource(BetterPlayerPlugin.kt:277)
at com.jhomlala.better_player.BetterPlayerPlugin.onMethodCall(BetterPlayerPlugin.kt:151)
at com.jhomlala.better_player.BetterPlayerPlugin.onMethodCall(BetterPlayerPlugin.kt:138)
at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:262)
at io.flutter.embedding.engine.dart.DartMessenger.invokeHandler(DartMessenger.java:295)
at io.flutter.embedding.engine.dart.DartMessenger.lambda$dispatchMessageToQueue$0$io-flutter-embedding-engine-dart-DartMessenger(DartMessenger.java:319)
at io.flutter.embedding.engine.dart.DartMessenger$$ExternalSyntheticLambda0.run(Unknown Source:12)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:246)
at android.app.ActivityThread.main(ActivityThread.java:8633)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:602)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1130)
)
#0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:653:7)
#1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:296:18)
#2      MethodChannelVideoPlayer.setDataSource (package:better_player/src/video_player/method_channel_video_player.dart:118:5)
#3      VideoPlayerController._setDataSource (package:better_player/src/video_player/video_player.dart:408:5)
#4      BetterPlayerController._setupDataSource (package:better_player/src/core/better_player_controller.dart:444:9)
#5      BetterPlayerController.setupDataSource (package:better_player/src/core/better_player_controller.dart:274:5)

问题原因 #

该异常源于ExoPlayer的API变更：MediaSource.Factory#setDrmSessionManagerProvider不再允许传入null值，也不会自动实例化DefaultDrmSessionManagerProvider，必须显式传入该类的实例。当前使用的better_player插件版本未适配此变更，导致调用该方法时传入null触发空指针异常。

解决方案 #

1. 更新better_player到最新版本 #

插件官方大概率已修复此适配问题，执行以下命令更新插件：

flutter pub upgrade better_player

更新完成后，清理项目缓存并重新运行：

flutter clean
flutter pub get
flutter run

2. 手动修改插件代码（应急方案） #

若无法更新插件，可临时修改插件源码：

• 找到项目中better_player插件的BetterPlayer.kt文件（路径通常为flutter/.pub-cache/hosted/pub.dev/better_player-xxx/lib/android/src/main/kotlin/com/jhomlala/better_player/BetterPlayer.kt）
• 定位到buildMediaSource方法（约第430行），找到调用setDrmSessionManagerProvider(null)的代码
• 将其替换为：

  .setDrmSessionManagerProvider(DefaultDrmSessionManagerProvider())
  

• 修改后重新编译项目

3. 排查依赖冲突 #

若更新插件后问题仍存在，可能是项目中其他依赖升级了ExoPlayer版本，导致版本不兼容。执行以下命令查看依赖树：

flutter pub deps

确认ExoPlayer的版本，必要时在pubspec.yaml中强制统一版本（需根据实际情况调整版本号）：

dependency_overrides:
  exoplayer_core: '2.X.X'
  exoplayer_dash: '2.X.X'

内容的提问来源于stack exchange，提问作者Omar Naser