Android : Issue positionning customLinear Layout

I've created a custom Linear layout in order to have "square" layout fitting the width of its parent but I'm having trouble positioning it with another LinearLayout. I want the LinearLayout to be just below the SquareLinearLayout and I got this (both layout are top aligned):

I've tried android:parentAlignBottom="true" and android:gravity="bottom" but nothing works for me ...

Here is my layout xml :

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.dekajoo.rpg.MainActivity" >

    <com.dekajoo.rpg.custom_layouts.SquareLinearLayout
        android:id="@+id/game_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center"
        android:orientation="vertical"
        android:background="#f00" />

    <android:LinearLayout
        android:id="@+id/control_bar"
        android:layout_width="match_parent"
        android:layout_height="100dip"
        android:background="#0f0"
        android:gravity="center"
        android:orientation="horizontal" />

</RelativeLayout>

And here is my SquareLinearLayout class :

package com.dekajoo.rpg.custom_layouts;

import android.content.Context;
import android.util.AttributeSet;
import android.widget.LinearLayout;

public class SquareLinearLayout extends LinearLayout {

    public SquareLinearLayout(Context context) {
        super(context);
    }
    public SquareLinearLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    /*public SquareView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }*/

    @Override 
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        int width = MeasureSpec.getSize(widthMeasureSpec);
        int height = MeasureSpec.getSize(heightMeasureSpec);
        int size = width > height ? height : width;
        setMeasuredDimension(size, size);
    }
}

Thanks,