<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/content_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.udacity.nanodegree.androiddevelopers.stephen.popularmovies.MainActivityFragment"
    tools:showIn="@layout/activity_main">

    <GridView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/id_movies_grid"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:verticalSpacing="0dp"
        android:horizontalSpacing="0dp"
        android:numColumns="2"
        android:stretchMode="columnWidth"
        />
</FrameLayout>

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/content_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.udacity.nanodegree.androiddevelopers.stephen.popularmovies.MainActivityFragment"
    tools:showIn="@layout/activity_main">

    <GridView xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/id_movies_grid"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:verticalSpacing="0dp"
        android:horizontalSpacing="0dp"
        android:numColumns="auto_fit"
        android:stretchMode="columnWidth" />
</FrameLayout>

Use autofit for number of poster columns
Use autofit for number of poster columns
