如何從Android N中的URI獲取文件路徑

Question

從文件資源管理器打開視頻文件時，如何從Uri獲取文件路徑。

Uri主機為“內容”，而“ _data”返回null。

我想在同一目錄中獲取其他視頻，因此我必須獲取文件路徑。如果還有其他方法可以在沒有文件路徑的情況下獲取同一目錄中的視頻，那么它也對我有用。 非常感謝您的任何想法和解決方案。

Answer 1

活動代碼：

Uri muri;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    muri = getUriForFile("your activity", BuildConfig.APPLICATION_ID + ".provider", "file path");
} else {
    muri = Uri.fromFile("file path");
}

Answer 2

試試這個代碼。 它也適用於我在奧利奧（Oreo）。

/**
 * Method for return file path of Gallery image/ Document / Video / Audio
 *
 * @param context - context of the application or class
 * @param uri - uri to get the path
 * @return          - path of the selected image file from gallery
 */
public static String getPath(final Context context, final Uri uri)
{
    // check here to KITKAT or new version
    final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;

    // DocumentProvider
    if (isKitKat && DocumentsContract.isDocumentUri(context, uri))
    {
        // ExternalStorageProvider
        if (isExternalStorageDocument(uri))
        {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            if ("primary".equalsIgnoreCase(type))
            {
                return Environment.getExternalStorageDirectory() + "/"
                        + split[1];
            }
        }
        // DownloadsProvider
        else if (isDownloadsDocument(uri))
        {
            final String id = DocumentsContract.getDocumentId(uri);

            final Uri contentUri = ContentUris.withAppendedId(
                    Uri.parse("content://downloads/public_downloads"),
                    Long.valueOf(id));

            return getDataColumn(context, contentUri, null, null);
        }
        // MediaProvider
        else if (isMediaDocument(uri))
        {
            final String docId = DocumentsContract.getDocumentId(uri);
            final String[] split = docId.split(":");
            final String type = split[0];

            Uri contentUri = null;

            if ("image".equals(type))
            {
                contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
            }
            else if ("video".equals(type))
            {
                contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
            }
            else if ("audio".equals(type))
            {
                contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
            }

            final String selection = "_id=?";
            final String[] selectionArgs = new String[] { split[1] };

            return getDataColumn(context, contentUri, selection,
                    selectionArgs);
        }
    }
    // MediaStore (and general)
    else if ("content".equalsIgnoreCase(uri.getScheme()))
    {
        // Return the remote address
        if (isGooglePhotosUri(uri))
            return uri.getLastPathSegment();

        return getDataColumn(context, uri, null, null);
    }
    // File
    else if ("file".equalsIgnoreCase(uri.getScheme()))
    {
        return uri.getPath();
    }

    return null;
}

/**
 * Get the value of the data column for this Uri. This is useful for
 * MediaStore Uris, and other file-based ContentProviders.
 *
 * @param context           - The context.
 * @param uri               - The Uri to query.
 * @param selection         - (Optional) Filter used in the query.
 * @param selectionArgs     - (Optional) Selection arguments used in the query.
 * @return                  - The value of the _data column, which is typically a file path.
 */
private static String getDataColumn(Context context, Uri uri,
                                   String selection, String[] selectionArgs)
{
    Cursor cursor = null;
    final String column = "_data";
    final String[] projection = { column };

    try
    {
        cursor = context.getContentResolver().query(uri, projection,
                selection, selectionArgs, null);

        if (cursor != null && cursor.moveToFirst())
        {
            final int index = cursor.getColumnIndexOrThrow(column);
            return cursor.getString(index);
        }
    }
    finally
    {
        if (cursor != null)
            cursor.close();
    }

    return null;
}

/**
 * @param uri      - The Uri to check.
 * @return         - Whether the Uri authority is ExternalStorageProvider.
 */
private static boolean isExternalStorageDocument(Uri uri)
{
    return "com.android.externalstorage.documents".equals(uri.getAuthority());
}

/**
 * @param uri       - The Uri to check.
 * @return          - Whether the Uri authority is DownloadsProvider.
 */
private static boolean isDownloadsDocument(Uri uri)
{
    return "com.android.providers.downloads.documents".equals(uri.getAuthority());
}

/**
 * @param uri       - The Uri to check.
 * @return          - Whether the Uri authority is MediaProvider.
 */
private static boolean isMediaDocument(Uri uri)
{
    return "com.android.providers.media.documents".equals(uri.getAuthority());
}

/**
 * @param uri       - The Uri to check.
 * @return          - Whether the Uri authority is Google Photos.
 */
private static boolean isGooglePhotosUri(Uri uri)
{
    return "com.google.android.apps.photos.content".equals(uri.getAuthority());
}

此代碼需要READ_EXTERNAL_STORAGE權限：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

應在運行時向用戶請求此權限，因為這是危險的權限。