TableLayout, android:layout_weight, and include

I have a layout with 6 included layouts in a TableLayout. I want to do this in landscape mode, because a ScrollView would be awkward in my scenario.

I have a 48dp-high horizontal layout, which contains a square ImageView, a SeekBar with full weight, and a square ImageButton. I set the drawables for the ImageView in Java.

In the main layout, I use an include for each one and I am trying to even out the columns, because they only take up half the screen, by the way this is an activity with Theme.Holo.Dialog as its theme.

However, when I run the app, I get a 40-60% unbalanced view. Why? What am I doing wrong?

Part of layout-land/main.xml

<LinearLayout
     xmlns:android="http://ift.tt/nIICcg"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
      ... >
...
<TableLayout
    android:layout_width="match_parent"
    android:layout_weight="1"
    android:stretchColumns="1"
    android:layout_height="wrap_content">

    <TableRow android:layout_width="match_parent" android:layout_height="wrap_content">
        <include android:layout_weight="1" layout="@layout/toast_item" android:id="@+id/systemToast"/>
        <include android:layout_weight="1" layout="@layout/toast_item" android:id="@+id/ringerToast"/>
    </TableRow>

    <TableRow android:layout_width="match_parent" android:layout_height="wrap_content">
        <include android:layout_weight="1" layout="@layout/toast_item" android:id="@+id/notifyToast"/>
        <include android:layout_weight="1" layout="@layout/toast_item" android:id="@+id/mediaToast"/>
    </TableRow>

    <TableRow android:layout_width="match_parent" android:layout_height="wrap_content">
        <include android:layout_weight="1" layout="@layout/toast_item" android:id="@+id/alarmToast"/>
        <include android:layout_weight="1" layout="@layout/toast_item" android:id="@+id/inCallToast"/>
    </TableRow>

</TableLayout>
...
</LinearLayout>

layout-land/toast_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://ift.tt/nIICcg"
   android:layout_width="0dp"
   android:layout_height="48dp"
   android:layout_marginLeft="8dp"
   android:layout_marginRight="8dp"
   android:orientation="horizontal"
   android:gravity="center_vertical">

<ImageView
    android:id="@+id/icon"
    android:src="@drawable/ic_audio_alarm"
    android:layout_width="48dp"
    android:layout_height="48dp"
    android:scaleType="center"
    android:clickable="false"
    android:layout_weight="0"/>
<SeekBar
    android:layout_width="0dp"
    android:layout_height="48dp"
    android:layout_weight="1"
    android:gravity="center_vertical"
    android:layout_marginLeft="4dp"
    android:maxHeight="1000dp"
    android:layout_marginRight="4dp"
    android:id="@+id/seekbar"/>
<ImageButton
    android:id="@+id/schedules"
    android:layout_width="48dp"
    android:layout_height="match_parent"
    android:scaleType="center"
    android:layout_weight="0"
    android:src="@drawable/ic_action_event"
    android:background="?android:attr/selectableItemBackground"
/>
</LinearLayout>