I want to make a layout similar to this one:

Four square buttons on the screen - each of those using half of the screen with/screen height (whichever is smaler).

I already tried to achieve this by using a LinearLayoutbut the buttons are ending up using the correct width, but still having the height of the background (not square any more).

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout android:layout_width="fill_parent"
    android:layout_height="wrap_content">
    <Button android:layout_height="wrap_content" style="@style/CKMainButton"
        android:layout_width="fill_parent" android:text="@string/sights"
        android:id="@+id/ApplicationMainSight" android:layout_toLeftOf="@+id/ApplicationMainEvent"></Button>

    <Button android:layout_height="wrap_content" style="@style/CKMainButton"
        android:layout_width="fill_parent" android:text="@string/sights"
        android:id="@+id/ApplicationMainSight" android:layout_toLeftOf="@+id/ApplicationMainEvent"></Button>
</LinearLayout>

<LinearLayout android:layout_width="fill_parent"
    android:layout_height="wrap_content">
    <Button android:layout_height="wrap_content" style="@style/CKMainButton"
        android:layout_weight="1" android:layout_width="fill_parent"
        android:text="@string/usergenerated" android:id="@+id/ApplicationMainUserGenerated"></Button>
    <Button android:layout_height="wrap_content" style="@style/CKMainButton"
        android:layout_weight="1" android:layout_width="fill_parent"
        android:text="@string/tours" android:id="@+id/ApplicationMainTour"></Button>
</LinearLayout>
</LinearLayout>

It's looking like this:

How can i acchieve the Layout to look like the image above?