How exactly this is done varies a little bit between different versions of OS X. In 10.9 To press the up arrow key, you’d write key code 126. Here’s a list of some good to know These are probably easier for most people to remember than their key code equivalent.

Mobile application development is the hottest thing in the programming world right now. The two most popular mobile platforms are Android and iOS (Apple). Although the numbers tend to fluctuate frequently, it seems that Android has taken the top spot from Apple. In the United States, at least 50% of all smartphone users have Android devices.

Globally, almost 70% of people use Android. If it seems like a popular platform that you should be, you are right! Not only is Android popular, but it could also become a very profitable platform once you start creating your own apps. Android Basics Android is based on a custom set of APIs that uses the Java programming language. If you already have some experience in Java, you are one step ahead of the curve.

If not, consider taking the to get up to speed in Java programming quickly. Each android application is comprised of four unique components.

Combined, these four components create all Android applications currently available via the Google Play Store or other outlets such as the Amazon App Store. You can learn more about these components in. Activities In Android, an activity is any single screen with a user interface. A good example is an email application. One activity shows you the inbox, another activity is used to compose new emails, and another activity allows you to read emails.

For the uninitiated, this may seem like extra work. Actually, this makes your job as an Android programmer much easier because the modular design allows you to change one aspect of the application without affecting the rest.

For instance, you may want a different color scheme when users create a new email that differs from colors used in the rest of the app. Using activities makes this a very simple task. Services Services run in the background. They are responsible for long-running operations or performing work that does not require user interaction. Services do not have a user interface.

Music players often run as services so the music will continue to play in the background even when the user switches to a different screen. Another popular service implementation is retrieving background data. For instance, if you ever use Gmail, you are familiar with push notifications. A service running in the background checks for new mail periodically without manual intervention from the user. This is a perfect example of a service in action.

Content Providers Content providers help manage application data. In the Android operating system, data can be stored within the file system, in a separate SQLite database, on the Web, or in other storage locations such as a microSD card. You can learn more about accessing and modifying storage locations in. Built into the Android system is an excellent example of a content provider. Contact information stored in the “Contacts” app can be queried by other applications.

This application is able to read or write information to the contacts database using content providers. Broadcast Receivers This component is responsible for responding to system wide broadcast announcements. Although most broadcasts are initiated by the Android system, your application can also create broadcasts that let other system applications know what is going on. Free studio screenshot for mac. The broadcast receiver is responsible for “listening” for broadcasts and performing some action when a broadcast is detected. This could be as simple as a status bar notification or it could start another activity or service automatically.