Android 29/Q上MediaScanner scanFile/CameraRoll的替代方案

Question

Google Play Store对Android范围内的应用程序存储设置了新的要求，使用清单标志requestLegacyExternalStorage
我的应用程序正在使用React Native community提供的CameraRoll软件包，该软件包尚不支持作用域存储（并且需要requestLegacyExternalStorage标志才能工作），时间非常短（2021年5月5日）。CameraRoll还有其他选择吗？这里的目标是在用户图库应用程序中显示图像，比如谷歌照片或供应商默认图库，而无需在用户端执行额外操作。

Google Play原创消息：

    Starting May 5th, you must let us know why your app requires broad storage access APPNAME 14 avr. 2021 19:26

    We've detected that your app contains the requestLegacyExternalStorage flag in the manifest file of 1 or more of your app bundles or APKs.

    Developers with apps on devices running Android 11+ must use Scoped Storage to give users better access control over their device storage. To release your app on Android 11 or newer after May 5th, you must either:

    Update your app to use more privacy friendly best practices, such as the Storage Access Framework or Media Store API
    Update your app to declare the All files access (MANAGE_EXTERNAL_STORAGE) permission in the manifest file, and complete the All files access permission declaration in Play Console from May 5th
    Remove the All files access permission from your app entirely

    For apps targeting Android 11, the requestLegacyExternalStorage flag will be ignored. You must use the All files access permission to retain broad access.

    Apps requesting access to the All files access permission without a permitted use will be removed from Google Play, and you won't be able to publish updates.

Answer 1

深入研究ReactNative CameraRoll软件包，它不仅仅是简单地扫描文件，让操作系统显示在用户库应用程序中。这里的解决方案是一些再强调：

>

映像需要在公共目录中才能显示（=读取访问权限）在任何库应用程序中，因此不在应用程序外部存储中：

• 不是：storage/android/data/com。示例/图片
• 在图片或DCIM或下载（检查环境.目录_DCIM）

需要一个android的本地包

代码：

反应原生部分：

import RNFS from 'react-native-fs'
const { PNModule } = ReactNative.NativeModules

try {
    if (Platform.OS === 'android' && Platform.Version >= 29) {
        // Google ask that the requestLegacyExternalStorage is no longer used when targeting android 11, and use
        // the scoped storage or the new global permission, see https://gitlab.inria.fr/floristic/pn-mobile-test/-/issues/417
        // Solution here, custom module which use the MediaStore API and copy the file to the DCIM folders.
        const segments = path.split('/')
        const fileName = segments[segments.length - 1]

        const fileUriPath = await PNModule.moveToMediaStore(path.replace('file://', ''), fileName)
        if (!fileUriPath) {
            return null
        }
        const scanResult = await RNFS.scanFile(fileUriPath)
        if (fileUriPath.startsWith('file:///')) {
            return fileUriPath
        }
        return `file://${fileUriPath}`
    }
    return await CameraRoll.save(path)
} catch (error) {
    console.error(error)
}

本机软件包（别忘了用你的应用文件夹替换APPNAME）

    @ReactMethod
    public void moveToMediaStore(String filePath, String fileName, Promise promise) {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.Q) {
            promise.resolve(null);
            return;
        }
        ContentValues values = new ContentValues();
        values.put(MediaStore.Images.Media.DISPLAY_NAME, fileName);
        values.put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg");

        values.put(MediaStore.MediaColumns.RELATIVE_PATH, Environment.DIRECTORY_DCIM + "/APPNAME");
        values.put(MediaStore.MediaColumns.IS_PENDING, 1);

        ContentResolver resolver = getReactApplicationContext().getContentResolver();
        Uri imageUri = resolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);

        try {
            OutputStream fos = resolver.openOutputStream(imageUri);
            copy(new File(filePath), fos);
            values.clear();
            values.put(MediaStore.Video.Media.IS_PENDING, 0);
            resolver.update(imageUri, values, null, null);
            promise.resolve(getNameFromContentUri(getReactApplicationContext(), imageUri));
        } catch (Exception e) {
            e.printStackTrace();
            promise.reject(e);
        }
    }

    @RequiresApi(api = Build.VERSION_CODES.Q)
    public static void copy(File src, OutputStream out) throws IOException {
        try (InputStream in = new FileInputStream(src)) {
            FileUtils.copy(in, out);
        }
    }

    // From https://stackoverflow.com/a/64359655/1377145
    public static String getNameFromContentUri(Context context, Uri contentUri){
        ContentResolver contentResolver = context.getContentResolver();
        Cursor cursor = contentResolver.query(contentUri, null, null, null, null);
        cursor.moveToFirst();
        String document_id = cursor.getString(0);
        document_id = document_id.substring(document_id.lastIndexOf(":") + 1);
        cursor.close();

        cursor = contentResolver.query(
            android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
            null, MediaStore.Images.Media._ID + " = ? ", new String[]{document_id}, null);
        cursor.moveToFirst();
        String path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
        cursor.close();
        return path;
    }