Remove extra space around GridView programmatically

I am trying to make a GridView programmatically in my java class and it all works fine. The problem is the auto-generated 5 pixel padding around the GridView. In the xml I manage to remove it using:

android:listSelector="@null"

But I do not manage to do anything similar in java. I have tried some workarounds like making the GridView 10 pixels larger then the actual screen with no luck.

Does anyone have any code for this?

Edit:

The answer by me does not solve the problem. There is still a bounty going. Here is my GridView code:

    GridView gridView = new GridView(this);
    gridView.setNumColumns(someInt);
    gridView.setAdapter (new MyCustomAdapter(this));
    gridView.setLayoutParams(new GridView.LayoutParams(
            customValue,
            LayoutParams.FILL_PARENT,
            Gravity.CENTER_HORIZONTAL)
    );