You’ve now completed the MainActivity
’s GUI. The Graphical Layout editor’s toolbar (Fig. 4.14) contains various buttons that enable you to preview the design for other screen sizes and orientations. In particular, you can view thumbnail images of many screen sizes and orientations by clicking the down arrow next to the button and selecting either Preview Representative Sample or Preview All Screen Sizes. For each thumbnail, there are + and – buttons that you can click to zoom in and out. Figure 4.14 overviews some of the buttons in the Graphical Layout editor’s toolbar.