Generally the splash page displays an image of the App on launch of the app. Most of time its just an single image that is intended to be displayed.Depending of the size of image and device it runs, it may not fit the screen fully and there may be space on right/bottom of screen, in other words its left aligned and is not equally spaced from the screen corner.
To have it display in the center, use the android:layout_gravity="center"attribute as show below:
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:src="@drawable/loading_screen"/>