Android Oreo如何从uri获取真实路径？

Question

我正在使用这段代码从URI中获取真实路径。在Marshmallow版本上可以运行，但在Oreo版本上无法运行：

private String getPathNew(Activity activity, Uri uri) { 
    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(activity, contentUri, null, null);
    }
    return null;
}

public 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 column_index = cursor.getColumnIndexOrThrow(column);
            return cursor.getString(column_index);
        }
    } finally {
        if (cursor != null)
            cursor.close();
    }
    return null;
}

我做错了什么？

- Ravi Dhakad

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可能与https://dev59.com/bGYs5IYBdhLWcg3wBvRp重复。 - shizhen

@shizhen 不是的。这是一个奇怪的“bug”，只出现在最近的Android版本中，比如Oreo。 - Chen Li Yong

@ChenLiYong 这个错误是由于在Android 7.0中首次引入了文件权限策略的变更所造成的。你要查找的问题可以在这里找到：https://dev59.com/5aDia4cB1Zd3GeqPFpDl。 - Kartik Ohri

@KartikOhri 很有趣。谢谢！ - Chen Li Yong

这个解决方案对我很好用：https://dev59.com/alQJ5IYBdhLWcg3w8anH - Kareem Alsaifi

Answer 1

 public static String getRealPathFromURI(Context context, Uri contentUri) {
    String[] proj = {MediaStore.Images.Media.DATA};
    Cursor cursor = context.getContentResolver().query(contentUri, proj, null, null, 
                                                                               null);
    if (cursor != null) {
        int column_index = 
        cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToFirst();
        return cursor.getString(column_index);
    }
    return null;
}

- Ami Trambadia

Answer 2

public static String getRealPathFromUri(final Context context, Uri uri) {
        final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
        // DocumentProvi`enter code here`der
        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];
                }
                // TODO handle non-primary volumes
            }
            // 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 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.
     */
    public 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 column_index = cursor.getColumnIndexOrThrow(column);
                return cursor.getString(column_index);
            }
        } finally {
            if (cursor != null)
                cursor.close();
        }
        return null;
    }
    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is ExternalStorageProvider.
     */
    public 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.
     */
    public 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.
     */
    public static boolean isMediaDocument(Uri uri) {
        return "com.android.providers.media.documents".equals(uri.getAuthority());
    }

- Lewis Jack

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从URI获取路径 在Android所有版本中使用以下类。访问任何类型的文件。 - undefined