Android Application Development For Dummies, 2nd Edition

Adding an Image to Your Application

Although looking at text is fun, the truly interesting components are added via input mechanisms and images. The following sections demonstrate how to include images in your application — it’s time to put some stuff on the screen!

Placing an image onscreen

The first element to add to the screen is the phone image (refer to Figures 4-2 and 4-3), so first you need the phone image, of course. You can download an image from this book’s source code, available from this book’s website, or you can use your own.

Why you should worry about density folders

Android supports various screen sizes and densities. Elsewhere in this chapter, we mention placing an image in the mdpi folder, which is for medium-density devices. What about small- and large-density devices? If Android cannot find the requested resource in the desired density, it opts for a density of the resource it can find. If your device has a high-density screen, the image is stretched out and most likely quite pixilated. If your device has a low-density device, the image is compressed to fit within the screen dimensions. To avoid this problem, create multiple versions of your image to target multiple screen densities. For more information, see the Supporting Multiple Screens page in the Android documentation at http://developer.android.com/guide/practices/screens_support.html .

Adding images to a project is simple: Drag them from the folder where they’re stored to the res/drawable-mdpi folder, ...