How to create a Android GridView that overflows and is 2D scrollable

Question

i just want to implement a 2D scrollable Gridview that overflows the screen. My basic idea was implementing a GridView inside a simple scrollview. This GridView should include some Gridfields which are editable like a multipictureframe but for text.

I just basically created it as the following:

<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content">
        <GridView
            android:id="@+id/sessionGrid"
            android:layout_width="FIX-WIDTH-IN-DP"
            android:layout_height="FIX-HEIGHT-IN-DP"
            android:layout_margin="@dimen/padding_outer_border"
            android:columnWidth="@dimen/dashboard_column_width"
            android:background="@color/br_gray_light"
            android:gravity="center"
            android:horizontalSpacing="@dimen/spacing"
            android:numColumns="auto_fit"
            android:stretchMode="columnWidth"
            android:verticalSpacing="@dimen/spacing">
        </GridView>
    </LinearLayout>
</ScrollView>

This creates a proper gridview which is scrollable vertically. But i cannot get it working to make scrollable in the horizontal way too.

The following image describes this a little more plastic (Sorry for the plain links, but i am not allowed to post images directly here)

https://i.stack.imgur.com/BBpYo.png http://redphoenix.de/data/code/problem.png

I would be very thankfull for giving me some advice here, if my approach is totally not okay i would be glad to get some hints or other approaches here. Much thanks in advance