[android] android: how to align image in the horizontal center of an imageview?

For me android:gravity="center" did the trick in the parent layout element.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:gravity="center"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/fullImageView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:adjustViewBounds="true"
        android:contentDescription="@string/fullImageView"
        android:layout_gravity="center" />

</LinearLayout>