如何在Xamarin.Forms中多选音视频文件并配置MediaPlugin创建播放列表

Hey there! Let's get your playlist feature up and running. You're on the right track with exploring plugins—since Xamarin.Forms doesn't have a built-in multi-file picker, third-party plugins are the way to go. Let's break down how to use MediaPlugin first, plus cover Android configuration and alternative options if needed.

Step 1: Finalize Android Configuration for MediaPlugin #

First, let's make sure your Android project is set up correctly, since that's where you're focusing right now:

1. Update AndroidManifest.xml:

   • Add these permissions inside the <manifest> tag (adjust based on Android version):

     <!-- For Android < 13 -->
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" android:maxSdkVersion="28" />
     <!-- For Android 13+ -->
     <uses-permission android:name="android.permission.READ_MEDIA_AUDIO" />
     <uses-permission android:name="android.permission.READ_MEDIA_VIDEO" />
     

   • Add android:requestLegacyExternalStorage="true" to your <application> tag (this helps with file access on Android 10+):

     <application android:requestLegacyExternalStorage="true" ...>
     

2. Handle Runtime Permissions:
   On Android 6.0+, you need to request storage permissions at runtime. You can use Xamarin.Essentials to do this easily:

   var status = await Permissions.CheckStatusAsync<Permissions.StorageRead>();
   if (status != PermissionStatus.Granted)
   {
       status = await Permissions.RequestAsync<Permissions.StorageRead>();
   }
   // For Android 13+, use Permissions.MediaAudio or Permissions.MediaVideo instead
   

Step 2: Use MediaPlugin to Select Multiple Files #

MediaPlugin does support multi-file selection—you just need to set the right option in PickMediaOptions:

Here's a code snippet you can use in your Xamarin.Forms page or ViewModel:

using Plugin.Media;
using Plugin.Media.Abstractions;

// Command to trigger file selection
public ICommand SelectMediaFilesCommand => new Command(async () =>
{
    // Check if media plugin is available
    if (!CrossMedia.Current.IsPickMediaSupported)
    {
        await Application.Current.MainPage.DisplayAlert("Oops", "Media picking isn't supported on this device.", "OK");
        return;
    }

    // Configure picker for multiple audio/video files
    var options = new PickMediaOptions
    {
        SelectionMode = MediaSelectionMode.Multiple,
        // Filter to only show audio/video files (optional but recommended)
        MediaType = MediaType.AllMedia // Or use MediaType.Audio / MediaType.Video
    };

    var selectedFiles = await CrossMedia.Current.PickMediaAsync(options);

    if (selectedFiles != null && selectedFiles.Any())
    {
        // Store these file paths for your playlist
        foreach (var file in selectedFiles)
        {
            var filePath = file.Path;
            // Add filePath to your playlist collection (e.g., ObservableCollection<string>)
            PlaylistItems.Add(filePath);
        }

        // Save the playlist to local storage (e.g., SQLite, JSON file)
        await SavePlaylistAsync(PlaylistItems);
    }
});

Step 3: Save Your Playlist #

Once you have the selected file paths, you'll want to persist the playlist. A simple way is to save it as a JSON file using Xamarin.Essentials:

using System.Text.Json;
using Xamarin.Essentials;

private async Task SavePlaylistAsync(List<string> playlistPaths)
{
    var json = JsonSerializer.Serialize(playlistPaths);
    await FileSystem.WriteAllTextAsync(FileSystem.AppDataDirectory + "/playlist.json", json);
}

// To load the playlist later
private async Task<List<string>> LoadPlaylistAsync()
{
    var filePath = FileSystem.AppDataDirectory + "/playlist.json";
    if (File.Exists(filePath))
    {
        var json = await FileSystem.ReadAllTextAsync(filePath);
        return JsonSerializer.Deserialize<List<string>>(json);
    }
    return new List<string>();
}

Alternative: Use FilePicker Plugin for More Control #

If MediaPlugin doesn't fit your needs (e.g., you want more file type filtering), the FilePicker Plugin is a great alternative. It's specifically built for file selection and supports multi-file picks:

1. Install the NuGet package for the plugin.
2. Android configuration is similar (same permissions as above).
3. Code example for selection:

   using Plugin.FilePicker;
   using Plugin.FilePicker.Abstractions;
   
   public async Task<List<string>> PickMultipleMediaFiles()
   {
       var filePaths = new List<string>();
       try
       {
           var files = await CrossFilePicker.Current.PickMultipleFilesAsync();
           if (files != null)
           {
               foreach (var file in files)
               {
                   // Check if it's an audio/video file (optional)
                   if (file.ContentType.StartsWith("audio/") || file.ContentType.StartsWith("video/"))
                   {
                       filePaths.Add(file.FilePath);
                   }
               }
           }
       }
       catch (Exception ex)
       {
           await Application.Current.MainPage.DisplayAlert("Error", $"Failed to pick files: {ex.Message}", "OK");
       }
       return filePaths;
   }
   

Key Notes #

• Always test on physical devices—emulators can have file access quirks.
• For Android 13+, make sure to request the new READ_MEDIA_AUDIO/READ_MEDIA_VIDEO permissions instead of READ_EXTERNAL_STORAGE.
• When saving playlists, use app-specific storage (via FileSystem.AppDataDirectory) to avoid issues with file access restrictions.

内容的提问来源于stack exchange，提问作者Dharm Rajodiya