android view layout children

onLayout.java

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int row, col, left, top;
        for (int i=0; i < getChildCount(); i++) {
            row = i / mColumnCount;
            col = i % mColumnCount;
            View child = getChildAt(i);
            left = col * child.getMeasuredWidth();
            top = row * child.getMeasuredHeight();

            child.layout(left, top, left + child.getMeasuredWidth(), top + child.getMeasuredHeight());
        }
    }