INTRO TO MOBILE APP DEVELOPMENT CMSC 150: Lecture 34

What is Android?  Open source OS for mobile devices  Google supported  Open Handset Alliance project  Based on Linux kernel  Apps programmed in Java (we already know Java)  Why aren’t we doing iOS?  Apps programmed in Objective C  One of the professors doesn’t have an iPhone 2

What is Android?  Android libraries provide access to mobile device features from your Java program  Like java.util, Squint  Mobile-adapted GUI components  Not Swing, but similar stuff  Best development platform is Eclipse   3

App Construction 4  Visual aspects specified as “resources”  Strings displayed in app – easier localization  GUI layouts in XML – can be changed without recompilation  Images used by app  Eclipse has a nice visual GUI editor  Drag-and-drop user interface construction  Eclipse also has a software emulator  So you don’t have to have an Android phone to have Android app development fun

GUI components 5  Android has layouts to organize GUI components  LinearLayout – components stacked vertically or horizontally  TableLayout – like a grid, but more flexible  etc…  GUI components are called “Views”  TextView == JLabel  EditText == JTextField  Button == JButton

App structure 6  Apps composed of multiple Activities  One Activity == one screen  Activity class is a lot like WindowManager  Provides basic functionality for user interaction e.g. onClicked() method kind of like buttonClicked()  Also manages App “life cycle” – provides methods called automatically when: App starts App suspends App resumes etc…

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Interaction with other Apps 8  View some data, dial a number, play a song, see a picture, send an or text message  Apps can use Intents to launch other apps  Intent class encapsulates the requested action and the data on which to perform it  Android matches the intent with the best App to provide the service, e.g. web browser, image gallery, phone dialer, etc.

Time for “Hello Android” 9

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Sources  Android Presentation by Manish K Chauhan (  Hello, Android, 3e by Ed Burnette  Android, How to Program, Deitel, Deitel and Deitel  11