Scrollable button list

i want to have a Scrollable button list in which buttons are disposed one next to the other horizontally and then return line and so on .. i tried to do this by putting a linear layout inside of a ScrollView .. but all it appears is the first line of buttons .. and the other buttons are crushed and don't appear !! any one could help please !!

here is my code xml

<ScrollView
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:id="@+id/scrollicons"
    android:layout_below="@+id/txt">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:background="@drawable/medicalsmall2"/>

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="5dp"
            android:background="@drawable/heartbeat"/>

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="5dp"
            android:background="@drawable/drops"/>

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="5dp"
            android:background="@drawable/teeth"/>

    </LinearLayout>

</ScrollView>