3.6 Modifying the User Interface

The user interface design for our activity is stored in a file named activity_main.xml which, in turn, is located under app -> res -> layout in the project file hierarchy. Once located in the Project tool window, double-click on the file to load it into the user interface Layout Editor tool which will appear in the center panel of the Android Studio main window:

Figure 3-6

In the toolbar across the top of the Layout Editor window is a menu (currently set to Pixel in the above figure) which is reflected in the visual representation of the device within the Layout Editor panel. A wide range of other device options are available for selection by clicking on this menu.

To change the orientation of the device representation between landscape and portrait simply use the drop down menu immediately to the left of the device selection menu showing the icon.

As can be seen in the device screen, the content layout already includes a label...