Create a Linear Layout

1. In Android Studio, from the res/layout directory, open the content_my.xml file.

   The BlankActivity template you chose when you created this project includes the content_my.xml file with a RelativeLayout root view and a TextView child view.

2. In the Preview pane, click the Hide icon to close the Preview pane.

   In Android Studio, when you open a layout file, you’re first shown the Preview pane. Clicking elements in this pane opens the WYSIWYG tools in the Design pane. For this lesson, you’re going to work directly with the XML.

3. Delete the <TextView> element.

4. Change the <RelativeLayout> element to <LinearLayout>.

5. Add the android:orientation attribute and set it to "horizontal".

6. Remove the android:padding attributes and the tools:context attribute.

The result looks like this:

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        tools:showIn="@layout/activity_my">

LinearLayout is a view group (a subclass of ViewGroup) that lays out child views in either a vertical or horizontal orientation, as specified by the android:orientation attribute. Each child of a LinearLayout appears on the screen in the order in which it appears in the XML.

Two other attributes, android:layout_width and android:layout_height, are required for all views in order to specify their size.

Because the LinearLayout is the root view in the layout, it should fill the entire screen area that's available to the app by setting the width and height to "match_parent". This value declares that the view should expand its width or height to match the width or height of the parent view.

For more information about layout properties, see the Layout guide.