Android 9 (Pie) ContentResolver 查询 MediaStore.Images.Media.EXTERNAL_CONTENT_URI 在 api 28 上返回 null

Question

I am fetching list of all the images, videos and audio files in the device. The below code is working fine on all devices up till android O (api 27). But it is not working on android Pie devices (api 28). Cursor returns null for the query

For Images

String[] proj = {MediaStore.Images.Media._ID,
                    MediaStore.Images.Media.DATA,
                    MediaStore.Images.Media.TITLE,
                    MediaStore.Images.Media.SIZE
            };
ContentResolver cr = context.getContentResolver();

Cursor imagescursor = context.getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
                    proj, null, null, "_size DESC");

For Video files

String[] proj = {MediaStore.Video.Media._ID,
                    MediaStore.Video.Media.DATA,
                    MediaStore.Video.Media.TITLE,
                    MediaStore.Video.Media.SIZE,
                    MediaStore.Video.Media.DURATION
            };
ContentResolver cr = context.getContentResolver();

Cursor videocursor = context.getContentResolver().query(MediaStore.Video.Media.EXTERNAL_CONTENT_URI,
                    proj, null, null, "_size DESC");

For Audio files

String[] proj = {MediaStore.Audio.Media._ID,
                    MediaStore.Audio.Media.DATA,
                    MediaStore.Audio.Media.DISPLAY_NAME,
                    MediaStore.Audio.Media.SIZE,
                    MediaStore.Audio.Media.DURATION};
ContentResolver cr = context.getContentResolver();

Cursor audiocursor = context.getContentResolver().query(MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                    proj, null, null, "_size DESC");

Please if anyone can help me out!

Answer 1

So I am able to find a workaround for this. Please let me know if anyone finds a better way to do it.

Step 1. local storage directory path

File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath());

Step 2. For images, Videos, Audios

private ArrayList<File> allShownImagesPath = new ArrayList<>();
private ArrayList<File> allShownVideoPath = new ArrayList<>();
private ArrayList<File> allShownAudioPath = new ArrayList<>();

Step 3. I am calling this method in background thread

public void searchDir(File dir) {
        //audio
        String mp3 = ".mp3";
        String ogg = ".ogg";
        String aac = ".aac";
        //video
        String mp4 = ".mp4";
        String mkv = ".mkv";
        String avi = ".avi";
        String webm = ".webm";
        //images
        String webp = ".webp";
        String png = ".png";
        String jpg = ".jpg";
        String gif = ".gif";

        File[] listFile = dir.listFiles();
        if (listFile != null) {
            for (File file : listFile) {


                if (file.isDirectory()) {
                    if (!file.getName().equals("Android") && !file.isHidden()) // will skip Android folder, hidden folders
                        searchDir(file);
                } else {
                    if (!file.isHidden()) { // will skip hidden files, totally up to you
                        String name = file.getName();
                        if (name.endsWith(mp3) || name.endsWith(ogg) || name.endsWith(aac)) { //Audio file
                            allShownAudioPath.add(file);
                        } else if (name.endsWith(mp4) || name.endsWith(mkv) || name.endsWith(avi) || name.endsWith(webm)) {  //Video file
                            allShownVideoPath.add(file);
                        } else if (name.endsWith(webp) || name.endsWith(png) || name.endsWith(jpg) || name.endsWith(gif)) { //Image file
                            allShownImagesPath.add(file);
                        }
                    }
                }
            }
        }
    }

Of course you can use more filters to find different files like .pdf , .docx , etc.

Not relevant to the question, but you can sort your files.

if (allShownImagesPath.size() > 0){

      File[] sortedImgFiles = allShownImagesPath.toArray(new File[0]);
      Arrays.sort(sortedImgFiles, LastModifiedFileComparator.LASTMODIFIED_COMPARATOR);
}