Align two-button layout left and right in Android

With Linear Layout

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

        <LinearLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1">

            <Button
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Prev"/>
        </LinearLayout>


        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Next"/>

</LinearLayout>

With Relative Layout

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

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Prev"
            android:layout_alignParentLeft="true"/>

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Next"
            android:layout_alignParentRight="true"/>
</RelativeLayout>

Use a RelativeLayout. There you can set android:layout_alignParentLeft and android:layout_alignParentRight. This should work for you:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:background="@android:color/white"
    android:gravity="bottom" >


    <RelativeLayout
        android:id="@+id/relativeLayout1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@android:color/black" >

        <Button
            android:id="@+id/button1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="prev"
            android:layout_alignParentLeft="true" />

        <Button
            android:id="@+id/button2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="next"
            android:layout_alignParentRight="true"/>

    </RelativeLayout>

</LinearLayout>