Android layout - why does RelativeLayout not take up entire screen on tablet?

Question

I am trying to get this layout to take up the entire screen on my Samsung Galaxy Tab 10.1, which has a screen size of roughly 800x1280.

i have the following xml in my res/layout-hdpi and res/layout, and my @drawable/background is in both res/drawable and res/drawable-hdpi where the background image in hdpi is 800x1280 size.

However, when i render the following, i can't get it to ever take up the entire screen. I've tried to get rid of ScrollView, change relativelayout to be linearlayout and set their layout_height="match_parent" but nothing changes... i've tried to clean project, uninstall app from the device before re-loading it... nothing seems to be working. Will someone please explain what's happening? I think i'm missing something really important.

(note: this works fine on my kindle fire and 7" tablets where the screen size is 600x1024 ish)

<?xml version="1.0" encoding="utf-8"?>
<ScrollView android:layout_width="fill_parent" android:layout_height="fill_parent"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <RelativeLayout 
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:background="@drawable/background">

        <RelativeLayout 
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/game_relativelayout_top_textview_definition_and_example"
            >

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="@drawable/game_screen_image_box"
                android:id="@+id/game_linearlayout_top_textview_definition_and_example"
                android:orientation="vertical"
                >
                <TextView
                    android:id="@+id/game_textview_definition"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="@dimen/padding_double"
                    android:layout_marginLeft="@dimen/padding_quadruple"
                    android:layout_marginRight="@dimen/padding_quadruple"
                    android:gravity="center_horizontal"
                    android:textSize="@dimen/font_size_slight_larger"
                    android:textColor="@android:color/black"
                    android:text="@string/filler" />

                <ImageView 
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="@dimen/padding_double"
                    android:src="@drawable/details_page_screen_divider"
                    android:contentDescription="@string/filler" />

                <TextView
                    android:id="@+id/game_textview_example"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="@dimen/padding_double"
                    android:layout_marginLeft="@dimen/padding_quadruple"
                    android:layout_marginRight="@dimen/padding_quadruple"
                    android:gravity="center_horizontal"
                    android:textSize="@dimen/font_size_slight_larger"
                    android:textStyle="italic"
                    android:textColor="@android:color/black"
                    android:text="@string/filler" />
            </LinearLayout>         

            <ImageView
                android:id="@+id/game_imageview_thumbs_down"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentRight="true"
                android:layout_alignParentBottom="true"
                android:layout_marginRight="@dimen/padding_quadruple"
                android:layout_marginBottom="@dimen/padding_quadruple"
                android:src="@drawable/game_screen_image_thumbs_down"
                android:contentDescription="@string/filler"
                />
            <ImageView
                android:id="@+id/game_imageview_thumbs_up"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toLeftOf="@id/game_imageview_thumbs_down"
                android:layout_alignParentBottom="true"
                android:layout_marginRight="@dimen/padding_double"
                android:layout_marginBottom="@dimen/padding_quadruple"
                android:src="@drawable/game_screen_image_thumbs_up"
                android:contentDescription="@string/filler"
                />  
        </RelativeLayout>

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/game_imageview_timer_foreground"
            android:src="@drawable/game_screen_image_timer_foreground"
            android:contentDescription="@string/filler"
            android:layout_below="@id/game_relativelayout_top_textview_definition_and_example"
            />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:id="@+id/game_imageview_timer_background"
            android:src="@drawable/game_screen_image_timer_background"
            android:contentDescription="@string/filler"
            android:layout_below="@id/game_relativelayout_top_textview_definition_and_example"
            />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical"
            android:layout_below="@id/game_imageview_timer_foreground"
            android:layout_marginTop="@dimen/padding_single">
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal">
                <Button
                    android:id="@+id/game_button_answer_choice_1"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:textSize="@dimen/font_size_regular"
                    android:text="@string/filler"
                    android:background="@drawable/game_screen_button_top_left"/>
                <Button
                    android:id="@+id/game_button_answer_choice_2"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:textSize="@dimen/font_size_regular"
                    android:text="@string/filler"
                    android:background="@drawable/game_screen_button_top_right"/>
            </LinearLayout>

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal">
                <Button
                    android:id="@+id/game_button_answer_choice_3"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:textSize="@dimen/font_size_regular"
                    android:text="@string/filler"
                    android:background="@drawable/game_screen_button_bottom_left"/>
                <Button
                    android:id="@+id/game_button_answer_choice_4"
                    android:layout_width="0dp"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:textSize="@dimen/font_size_regular"
                    android:text="@string/filler"
                    android:background="@drawable/game_screen_button_bottom_right"/>
            </LinearLayout>
        </LinearLayout>

    </RelativeLayout>
</ScrollView>

Answer 1

You should use either fill_parent or match_parent instead of wrap_content as, wrap_content takes only as much height as is needed by the content, but fill_parent or match_parent takes on the entire height.

Answer 2

Well, there are some things that you should take care of first, which are probably the reasons why other things to not to be processed in the right way. A relativeLayout doesn't have/need any "orientation" parameter, you should remove it. Moreover I'd recommend to use either fill_parent or match_parent and not both together. (note that match_parent achieves the same result but it is only available from API 8 onwards).

Ultimately, make sure your image has the amount of pixel you point there: mind the resolution of the image (ppi)