Android : Stroke disappear on one side after setting layout params in Android

I have set layout params to my grid in Android, and due to this, a stroke from one side disappear.

This is my code :

if (convertView == null) {
        LayoutInflater inflater = ((Activity) context).getLayoutInflater();
        convertView = inflater.inflate(R.layout.gridview_cell, parent, false);

        WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
        Display display = windowManager.getDefaultDisplay();

        int imgWidth = display.getWidth() / 2;
        int imgHeight = (int) (imgWidth * 1.5f);

        ViewGroup.LayoutParams lp = convertView.getLayoutParams();
        lp.width = imgWidth;
        lp.height = imgHeight;
        convertView.setLayoutParams(lp);

        holder = new ViewHolder();
        holder.day = (TextView) convertView.findViewById(R.id.dayDateTextView);
        holder.image = (ImageView) convertView.findViewById(R.id.dayImage);
        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }

And this is image showing the result :

I have tried changing layout params values, but it didn't worked. Thanks.