erpsuiteandroid/Apex/res/layout/activity_function_select.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=".FunctionSelectActivity" >

    <GridLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:columnCount="3"
         >

        <ImageButton
            android:id="@+id/ibtn_booking"
            android:layout_gravity="left"
            android:src="@drawable/ic_oceanbooking" />

        <ImageButton
            android:id="@+id/ibtn_info"
            android:layout_gravity="left"
            android:src="@drawable/ic_ocean_blinfo" />

        <ImageButton
            android:id="@+id/ibtn_detail"
            android:layout_gravity="left"
            android:src="@drawable/ic_container_detail" />

        <ImageButton
            android:id="@+id/ibtn_cargo"
            android:layout_gravity="left"
            android:src="@drawable/ic_cargo_tracking" />

        <ImageButton
            android:id="@+id/ibtn_doc"
            android:layout_gravity="left"
            android:src="@drawable/ic_down_doc" />

        <ImageButton
            android:id="@+id/ibtn_password"
            android:layout_gravity="left"
            android:src="@drawable/ic_password" />

        <ImageButton
            android:id="@+id/ibtn_exit"
            android:layout_gravity="left"
            android:src="@drawable/ic_exit" />

    </GridLayout>

</RelativeLayout>