public class GridViewImageAdapter extends BaseAdapter {

private Activity _activity;
private static Context _context;
private String _album_ID;
private int _sub_ID;

private ArrayList<Integer> _filePaths = new ArrayList<Integer>();

private int imageWidth;

public GridViewImageAdapter(Activity activity, ArrayList<Integer> filePaths,
        int imageWidth, String album_ID, int sub_ID, Context context)
{
    this._activity = activity;
    this._context = context;
    this._filePaths = filePaths;
    this.imageWidth = imageWidth;
    this._album_ID = album_ID;
    this._sub_ID = sub_ID;
}

@Override
public int getCount() {
    return this._filePaths.size();
}

@Override
public Object getItem(int position) {
    return this._filePaths.get(position);
}

@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ImageView imageView;
    if (convertView == null) {
        imageView = new ImageView(_activity);
    } else {
        imageView = (ImageView) convertView;
    }

        Bitmap image = decodeFile(_filePaths.get(position), imageWidth,
                imageWidth);

        imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
        imageView.setLayoutParams(new GridView.LayoutParams(imageWidth,
                imageWidth));
        imageView.setImageBitmap(image);

        // image view click listener
        imageView.setOnClickListener(new OnImageClickListener(position));

    return imageView;
}

class OnImageClickListener implements OnClickListener {

    int _postion;

    // constructor
    public OnImageClickListener(int position) {

            this._postion = position;
    }

    @Override
    public void onClick(View v) {
        // on selecting grid view image
        // launch full screen activity

        Intent i = new Intent(_activity, FullScreenViewActivity.class);
        i.putExtra("position", _postion);
        i.putExtra("album_ID", _album_ID);
        i.putExtra("sub_ID", _sub_ID);
        _activity.startActivity(i);
    }

}
}