Android: How to query a list of bucket name

Question

I want to retrieve only the name of the bucket (Albums). E.g. Camera, Download etc but not a list of Camera, Download etc from all the the photos so how do I retrieve one row each for each bucket name?

What I mean like in Gallery Application, you have albums first e.g. Camera. When you clicked on it, it show all the photos of the camera.

I can query the photos in a Camera Roll with the Where clause of the query. But what if I wanted only the name of each of the albums' name and not the photos, is it possible to query that? If I query all the photos and take only one row per set of photos, then it will be time consuming.

Please Help

Answer 1

I have the same problem and here is my solution (after tracing gallery source code) to get album name and the first image in it (can use as thumbnail for this album):

(Note that bucket repeat is removed by groupby & order technique)

    // which image properties are we querying
    String[] PROJECTION_BUCKET = {
            ImageColumns.BUCKET_ID,
            ImageColumns.BUCKET_DISPLAY_NAME,
            ImageColumns.DATE_TAKEN,
            ImageColumns.DATA};
    // We want to order the albums by reverse chronological order. We abuse the
    // "WHERE" parameter to insert a "GROUP BY" clause into the SQL statement.
    // The template for "WHERE" parameter is like:
    //    SELECT ... FROM ... WHERE (%s)
    // and we make it look like:
    //    SELECT ... FROM ... WHERE (1) GROUP BY 1,(2)
    // The "(1)" means true. The "1,(2)" means the first two columns specified
    // after SELECT. Note that because there is a ")" in the template, we use
    // "(2" to match it.
    String BUCKET_GROUP_BY =
            "1) GROUP BY 1,(2";
    String BUCKET_ORDER_BY = "MAX(datetaken) DESC";

    // Get the base URI for the People table in the Contacts content provider.
    Uri images = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;

    Cursor cur = getContentResolver().query(
            images, PROJECTION_BUCKET, BUCKET_GROUP_BY, null, BUCKET_ORDER_BY);

    Log.i("ListingImages"," query count=" + cur.getCount());

    if (cur.moveToFirst()) {
        String bucket;
        String date;
        String data;
        int bucketColumn = cur.getColumnIndex(
                MediaStore.Images.Media.BUCKET_DISPLAY_NAME);

        int dateColumn = cur.getColumnIndex(
                MediaStore.Images.Media.DATE_TAKEN);
        int dataColumn = cur.getColumnIndex(
                MediaStore.Images.Media.DATA);

        do {
            // Get the field values
            bucket = cur.getString(bucketColumn);
            date = cur.getString(dateColumn);
            data = cur.getString(dataColumn);

            // Do something with the values.
            Log.i("ListingImages", " bucket=" + bucket 
                    + "  date_taken=" + date
                    + "  _data=" + data);
        } while (cur.moveToNext());
    }