我在 Android 上的音频播放器不工作 - Xamarin

Question

我使用 Xamarin 编写 C# Android 应用程序。我写了这段代码：

protected MediaPlayer player;
protected override void OnCreate(Bundle savedInstanceState)
{
    base.OnCreate(savedInstanceState);
    SetContentView(Resource.Layout.layout1);
    this.Window.AddFlags(WindowManagerFlags.Fullscreen);

    player = new MediaPlayer();
    player.Reset();
    var fileDescriptor = Assets.OpenFd("MySound.mp3");
    player.SetDataSource(fileDescriptor.FileDescriptor);
    player.Prepare();
    player.Start();
}

MySound.mp3 文件直接在Assets 文件夹中。当我运行应用程序出现错误时：

Java.IO.IOException Message=Prepare failed.: status=0x1

与player.Prepare();

一致

怎么了？为什么它不起作用？

Answer 1

这似乎是 Android 设备上 MediaPlayer.Prepare() 的常见异常。快速搜索发现了这个：

https://social.msdn.microsoft.com/Forums/en-US/15f9c371-1b8d-4927-9555-f40e2829c377/mediaplayer-prepare-failed-stauts0x1?forum=xamarinandroid

匿名引用：

Hi, I wasted a lot of time, trying to find a solution to this issue on my side too. So I post here, just in case it is helping some people. My situation : I wanted to load an audio file from my assets (so not registered in my resources). I am using a similar code as Ike Nwaogu, except that I am using an AssetFileDescriptor to open my file (in my activity class code, so I have access to "Assets") :
string path = "Audio/myfile.ogg";
Android.Content.Res.AssetFileDescriptor afd = Assets.OpenFd(path);
MediaPlayer soundPlayer = new MediaPlayer();
 
if (afd != null)
{
    soundPlayer.Reset();
    soundPlayer.SetDataSource(afd.FileDescriptor);
    soundPlayer.Prepare();
    soundPlayer.Enabled = true;
    afd.Close();
}
I was failing on the Prepare(). I tried to add the access to external storage permissions (but it did make sense since it was loaded from my assets directly, I tried just in case).

Just by chance, by seeing other people samples on the forums, I added the afd.StartOffset, afd.DeclaredLength to the parameters:

soundPlayer.SetDataSource(afd.FileDescriptor, afd.StartOffset, afd.DeclaredLength);

and it worked ... I don't know if it just luck and if is going to fail again later or if there is a bug in API ...

根据各种消息来源，在设置 DataSource 时使用 getStartOffset 和 getLength 应该可以解决这个问题：

player.setDataSource(fileDescriptor.getFileDescriptor(), fileDescriptor.getStartOffset(), fileDescriptor.getLength());

或者，这里还有一些想法： Android MediaPlayer throwing "Prepare failed.: status=0x1" on 2.1, works on 2.2

https://forum.processing.org/two/discussion/6722/andriod-mediaplayer-prepare-failed-status-0x1

我在 Android 上的音频播放器不工作 - Xamarin

My audio player on Android doesn't work - Xamarin

c#

audio

android

xamarin