Android Programming: The Big Nerd Ranch Guide, 5th Edition

Laying Out the UI

Click the editor tab for the layout file, activity_main.xml. This will open the layout editor in the editor tool window (Figure 1.8). (If you do not see a tab for activity_main.xml, click the disclosure arrows to expand app/res/layout/ in the project tool window. Double-click activity_main.xml to open the file. If activity_main.xml opens but shows XML instead of the layout editor, click the Design tab near the top-right corner of the editor tool window.)

Figure 1.8  Layout editor

By convention, a layout file is named based on the activity it is associated with: Its name begins with activity_, and the ...