在 Xamarin 中播放 .wav 音频

问题描述

我正在尝试播放 .wav 音频文件，为此我遵循了 answer。

我遵循了这个答案，但我在 audio.Load(stream); 上收到一条错误消息说 System.NullReferenceException: Object reference not set to an instance of an object。

对我来说，问题似乎在于，audio.load() 找不到位于 Resource/raw 路径中的音频文件。

完整代码

private void Counter(object sender,EventArgs e)
{
    timer_countdown = new Timer();
    timer_countdown.Interval = 1000;
    timer_countdown.Elapsed += OnTimedEventIDCamera;
    timer_countdown.Enabled = true;
    timer_countdown.AutoReset = true;
    timer_countdown.Start();
}

private void OnTimedEventIDCamera(object source,ElapsedEventArgs e)
{
    Seconds++;

    if (Seconds == 3)
    {
        var stream = GetStreamFromFile("beepSound.wav");
        var audio = Plugin.SimpleAudioPlayer.CrossSimpleAudioPlayer.Current;
        audio.Load(stream);
        audio.Play();
    }
}

Stream GetStreamFromFile(string filename)
{
    var assembly = typeof(App).GetTypeInfo().Assembly;

    var stream = assembly.GetManifestResourceStream("yourprojectname." + filename);

    return stream;
}

解决方法

根据您的描述和代码，您在Android平台Resource/raw文件夹中有一个音频文件。如果您使用上面提供的代码，则无法获取音频文件且流为空。

您可以将 .wav 音频文件放入 Forms shared 并将 Build Action 设置为 Embedded Resource

 private void Btnwav(object sender,EventArgs e)
    {
        var stream = GetStreamFromFile("xxx.wav");
        var audio = Plugin.SimpleAudioPlayer.CrossSimpleAudioPlayer.Current;
        audio.Load(stream);
        audio.Play();
    }
    Stream GetStreamFromFile(string filename)
    {
        var assembly = typeof(App).GetTypeInfo().Assembly;

        var stream = assembly.GetManifestResourceStream("yourprojectname." + filename);

        return stream;
    }

更新：

我的项目名称是playvideo，添加minions.mp4

 private void Btnwav(object sender,EventArgs e)
    {
        var stream = GetStreamFromFile("minions.mp4");
        var audio = Plugin.SimpleAudioPlayer.CrossSimpleAudioPlayer.Current;
        audio.Load(stream);
        audio.Play();
    }
    Stream GetStreamFromFile(string filename)
    {
        var assembly = typeof(App).GetTypeInfo().Assembly;

        var stream = assembly.GetManifestResourceStream("playvideo." + filename);

        return stream;
    }