Create a Linear Layout

Open the activity_main.xml file from the res/layout/ directory.

Note: In Eclipse, when you open a layout file, you’re first shown the Graphical Layout editor. This is an editor that helps you build layouts using WYSIWYG tools. For this lesson, you’re going to work directly with the XML, so click the activity_main.xml tab at the bottom of the screen to open the XML editor.

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

First, delete the <TextView> element and change the <RelativeLayout> element to <LinearLayout>. Then add the android:orientation attribute and set it to "horizontal". The result looks like this:

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.

The other two 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.

Date: 2014-12-29; view: 1112