List all camera images in Android

问题:

How do you get a list of all camera images of an Android device?

Is it through the MediaStore? How?

回答1:

The Gallery app obtains camera images by using a content resolver over Images.Media.EXTERNAL_CONTENT_URI and filtering the results by Media.BUCKET_ID. The bucket identifier is determined with the following code:

public static final String CAMERA_IMAGE_BUCKET_NAME =
        Environment.getExternalStorageDirectory().toString()
        + "/DCIM/Camera";
public static final String CAMERA_IMAGE_BUCKET_ID =
        getBucketId(CAMERA_IMAGE_BUCKET_NAME);

/**
 * Matches code in MediaProvider.computeBucketValues. Should be a common
 * function.
 */
public static String getBucketId(String path) {
    return String.valueOf(path.toLowerCase().hashCode());
}

Based on that, here's a snippet to get all camera images:

public static List<String> getCameraImages(Context context) {
    final String[] projection = { MediaStore.Images.Media.DATA };
    final String selection = MediaStore.Images.Media.BUCKET_ID + " = ?";
    final String[] selectionArgs = { CAMERA_IMAGE_BUCKET_ID };
    final Cursor cursor = context.getContentResolver().query(Images.Media.EXTERNAL_CONTENT_URI, 
            projection, 
            selection, 
            selectionArgs, 
            null);
    ArrayList<String> result = new ArrayList<String>(cursor.getCount());
    if (cursor.moveToFirst()) {
        final int dataColumn = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        do {
            final String data = cursor.getString(dataColumn);
            result.add(data);
        } while (cursor.moveToNext());
    }
    cursor.close();
    return result;
}

For more info, review the ImageManager and ImageList classes of the Gallery app source code.