Our app needs a layout where we'll define a canvas to paint our graphics. The new project created by Android Studio makes a default layout file in the
app/res/layout/ folder (using the Android view or
app/src/main/res/layout using the Project view). Find the
activity_main.xml file and double-click on it to edit it.
There are two views of a layout file in the Android Studio editor: Design versus Text, selected by tabs on the lower-left hand side of the window pane. If the Design view tab is selected, you'll see an interactive editor with a simulated smartphone image, a palette of UI components on the left-hand side, and a Properties editor on the right-hand side. We're not going to use this view. If necessary, select the ...