getPicturePaths.java

private ArrayList<imageFolder> getPicturePaths(){
        ArrayList<imageFolder> picFolders = new ArrayList<>();
        ArrayList<String> picPaths = new ArrayList<>();
        Uri allImagesuri = android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
        String[] projection = { MediaStore.Images.ImageColumns.DATA ,MediaStore.Images.Media.DISPLAY_NAME,
                MediaStore.Images.Media.BUCKET_DISPLAY_NAME,MediaStore.Images.Media.BUCKET_ID};
        Cursor cursor = this.getContentResolver().query(allImagesuri, projection, null, null, null);
        try {
            if (cursor != null) {
                cursor.moveToFirst();
            }
            do{
                imageFolder folds = new imageFolder();
                String name = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DISPLAY_NAME));
                String folder = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.BUCKET_DISPLAY_NAME));
                String datapath = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA));

                //String folderpaths =  datapath.replace(name,"");
                String folderpaths = datapath.substring(0, datapath.lastIndexOf(folder+"/"));
                folderpaths = folderpaths+folder+"/";
                if (!picPaths.contains(folderpaths)) {
                    picPaths.add(folderpaths);

                    folds.setPath(folderpaths);
                    folds.setFolderName(folder);
                    folds.setFirstPic(datapath);//if the folder has only one picture this line helps to set it as first so as to avoid blank image in itemview
                    folds.addpics();
                    picFolders.add(folds);
                }else{
                    for(int i = 0;i<picFolders.size();i++){
                        if(picFolders.get(i).getPath().equals(folderpaths)){
                            picFolders.get(i).setFirstPic(datapath);
                            picFolders.get(i).addpics();
                        }
                    }
                }
            }while(cursor.moveToNext());
            cursor.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        for(int i = 0;i < picFolders.size();i++){
            Log.d("picture folders",picFolders.get(i).getFolderName()+" and path = "+picFolders.get(i).getPath()+" "+picFolders.get(i).getNumberOfPics());
        }
        return picFolders;
}