itcs4180/HW4/res/layout/activity_image_viewer.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/FrameLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/black"
    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=".ImageViewerActivity" >

    <ImageView
        android:id="@+id/imgViewer"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_gravity="center_horizontal"
        android:scaleType="centerInside" />

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom" >

        <Button
            android:id="@+id/btnPrev"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:onClick="onClickPrev"
            android:text="@string/btnPrev" />

        <Button
            android:id="@+id/btnBack"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:onClick="onClickBack"
            android:text="@string/btnBack" />

        <Button
            android:id="@+id/btnNext"
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:onClick="onClickNext"
            android:text="@string/btnNext" />
    </LinearLayout>

</FrameLayout>