Android 无法使用 VLC 设置字幕

Unable to Set Subtitles with VLC for Android

我在为 Android 启动 VLC 的 VideoPlayerActivity 时设置字幕位置时遇到问题。我的目标是 API 27 并使用 FileProvider 来允许访问文件。

根据文档here,如果您设置 "subtitles_location" extra,那么您可以提供字幕文件的路径。不幸的是,我似乎无法让它工作。

我看到 "Subtitles" 菜单项保持灰色,下载字幕似乎不会改变这种状态。点击时,"Select subtitle file" VLC 声明目录中没有字幕文件并且 URI 带有前缀,如预期的那样 "content://"。

视频文件和字幕文件共享相同的父目录,并使用 FileProvider 提供。

目标 API >= 24 时如何设置字幕文件?

更新:

下面是我如何通过意图启动 VideoPlayerActivity 的一些代码片段。

播放视频方法:

/**
 * Play a video using VLC media player. This method will play media by using
 * the VLC VideoPlayerActivity.
 *
 * @param activity         The current activity.
 * @param authority        The FileProvider authority.
 * @param vlcPackageName   The VLC package name.
 * @param vlcActivityName  The VLC activity name.
 * @param videoFile        The video file to play.
 * @param subtitlesFile    The subtitles file to play.
 * @param playbackPosition The playback position.
 * @param requestCode      The activity for result request code.
 */
public static void playVideo(
        AppCompatActivity activity,
        String authority,
        String vlcPackageName,
        String vlcActivityName,
        String vlcTitleExtra,
        String vlcPositionExtra,
        String vlcFromStartExtra,
        String vlcSubtitlesExtra,
        File videoFile,
        File subtitlesFile,
        long playbackPosition,
        int requestCode
) {
    Intent intent = new Intent(Intent.ACTION_VIEW);

    intent.setPackage(vlcPackageName);

    // Set component to VLC video player activity.
    intent.setComponent(new ComponentName(
            vlcPackageName,
            vlcActivityName
    ));

    // Set intent permission flags.
    intent.addFlags(Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION);
    intent.addFlags(Intent.FLAG_GRANT_PREFIX_URI_PERMISSION);
    intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
    intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

    // Set title and playback position.
    intent.putExtra(vlcTitleExtra, videoFile.getName());
    intent.putExtra(vlcPositionExtra, playbackPosition);
    intent.putExtra(vlcFromStartExtra, false);

    // Set video file location
    intent.setDataAndTypeAndNormalize(
            FileProvider.getUriForFile(
                    activity,
                    authority,
                    videoFile
            ),
            "video/*"
    );

    // Subtitles file provided, set location on intent.
    if (subtitlesFile != null) {
        intent.putExtra(
                vlcSubtitlesExtra,
                FileProvider.getUriForFile(
                        activity,
                        authority,
                        subtitlesFile
                )
        );
    }

    activity.startActivityForResult(intent, requestCode);
}

清单中的提供商定义

   <provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="com.masterwok.bitcast.fileprovider"
        android:exported="false"
        android:grantUriPermissions="true" >
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/paths" />
    </provider>

@xml/paths定义:

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-path
        name="Download"
        path="Download/"/>
</paths>

我能够通过使用未记录的 "item_location" 额外定义来解决这个问题:here.

当目标 API >= 24 时,这解决了权限问题。发生的事情是 VideoPlayerActivity 试图读取使用 FileProvider 提供的 URI 的父目录。如果非要我猜的话,我会说 Android 不允许这样做。

通过使用 "item_location" extra 传递 URI,我们可以绕过此限制。

我现在播放视频文件的方法如下:

/**
 * Play a video using VLC media player. This method will play media by using
 * the VLC VideoPlayerActivity.
 *
 * @param activity         The current activity.
 * @param vlcPackageName   The VLC package name.
 * @param vlcActivityName  The VLC activity name.
 * @param videoFile        The video file to play.
 * @param playbackPosition The playback position.
 * @param requestCode      The activity for result request code.
 */
public static void playVideo(
        AppCompatActivity activity,
        String vlcPackageName,
        String vlcActivityName,
        String vlcItemLocationExtra,
        String vlcTitleExtra,
        String vlcPositionExtra,
        String vlcFromStartExtra,
        File videoFile,
        long playbackPosition,
        int requestCode
) {
    Intent intent = new Intent(Intent.ACTION_VIEW);

    intent.setPackage(vlcPackageName);

    // Set component to VLC video player activity.
    intent.setComponent(new ComponentName(
            vlcPackageName,
            vlcActivityName
    ));

    // Set intent permission flags.
    intent.addFlags(Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION);
    intent.addFlags(Intent.FLAG_GRANT_PREFIX_URI_PERMISSION);
    intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
    intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

    // Set title and playback position.
    intent.putExtra(vlcTitleExtra, videoFile.getName());
    intent.putExtra(vlcPositionExtra, playbackPosition);
    intent.putExtra(vlcFromStartExtra, false);

    // Set video file location (subtitles are found by VLC by using parent directory).
    intent.putExtra(vlcItemLocationExtra, Uri.fromFile(videoFile));

    activity.startActivityForResult(intent, requestCode);
}