Learn Android in 20 concepts Starting to Android development 2015

Today, Android has hundreds of millions of mobile devices in over 190 countries throughout the world. And all accompanied by over 1.5 billion application downloads from Google Play every month. Some amazing numbers that many people have led them to want to contribute their bit, developing its own application. Who has not thought to have this idea that you can perform?

Therefore, and bringing my own experience as a developer of apps for Android, today we inaugurate a new section aimed at introducing us to develop applications for Android: the 'Learn Android in 20 concepts' section.

In this section we will review the 20 basics of API (Application Programming Interface) for Android to program an application on Android, from scratch. For those who do not know what an API , it is basically the functionality provided us (in this case Android) to program.

This does not mean that these 20 concepts you know everything, nor indeed that no other also important concepts. What is at issue is to explain here the most important general concepts to create a good structure of our application. On this basis, deepen more specific concepts (such as access to GPS) will be much easier.

The 20 concepts discussed in the section 'Learn Android in 20 concepts' are:

0. Beginning

1. Basis for an application

2. Resources of app

3. Activity class

Class 4. Fragment

5. Custom View

6. Chargers (Adapter)

7. The Intent class

8. Recipients of messages broadcast (Broadcast Receiver)

9. Prefencias an app (Shared Preferences)

10. SQLite Databases

11. Services (The Service class)

12. Asynchronous Tasks (The AsyncTask class)

13. Content Management (Content Provider)

14. The action bar ActionBar

15. Notices

16. Device Orientation

17. Animations

18. Widgets

19. Other concepts

20. Additional Information

The section will be weekly, but introduce more of a concept every week starting next week. This week we'll worry about leaving your computer ready to start programming in Android.

0. Beginning

The first will know that to program native applications on Android, we learn how to program in Java, knowing the OOP.

The first thing to do is prepare our development environment and know where to get any information. To do this, you must first know where all information for developers of Android is Google has prepared us a website for it, but we know that all the information is in English.:

Web Developer Android

On this website, we have 3 basic sections: Design, Development and Distribution. In them, we will have all the information on Google's recommendations for designing our app, all information on the API of Android and publish information to know our application, knowing how to promote it, announce ...

At the bottom, we will have additional information on Android, get the SDK (Software Development Kit), support ...

This will be our first step, unburden the development environment, for which we will go to Get the SDK, or we will click on the link below

Download the SDK

Once on the website, just to give you the link that says Download the SDK, and we will drop a version of the Eclipse development environment, customized for Android and ready with the latest SDK, the ADT plugin and emulators on which to test our application.

In the past Google I / O (2013), also announced the new Android Studio IDE , which can also be used instead of Eclipse, but we know they're still in beta. From the same page you can access the information at once. We have spoken before this new IDE , but in this tutorial we will use Eclipse.

Once we open our development environment, we can download all versions of Android if we want, as well as other extra packages. We will use the Android SDK Manager.

On the other hand, we can create as many emulators Android devices as you want: with different screen sizes, different versions of Android ... For this, we use the Android Virtual Device Manager (ADB), to which we can access from Eclipse or the route of our operating system commands:

Although the best way to have control over our devices will be learning to drive ADB from the command line, something we have also spoken . However, in Eclipse we can also manage our devices and get information of our device: from screenshots or see the files to send GPS coordinates or send a call. To do this, we will go to Window / Open perspective / Other ... / DDMS. The view of Eclipse DDMS (Dalvik Debug Monitor Server) will be very useful as we develop our applications. We have all the information on it at the following link:

DDMS

At this point, your computer is ready to create our first Android application. To do this, we will build on the steps we follow to Google recommends a simple app. All this information can be found on a Google trainings that we have prepared:

Training (Trainings) on Google Android

Creating a new Android project

Our section will end today following the second link, where we will create a new Android project. To do this, follow these steps:

1. Click on New
2. In the window that appears, open the folder and choose Android Android Application Project
3. In the next window, we enter the name of your application, the project name and the package name (this will be unique to our app, it will be that Google Play ID used to identify the application). Also introduce the minimum required version of Android and the version that compile (build our application from the code) our application.
4. After filling in all the fields as need or want, we go to the next screen, where we leave the default options.
5. On the next screen, we can create an icon for our application. To do this, it would be ideal to look at the Android design guidelines with regard to what is referred icons.
6. Finally, select an activity template on which to start work. We can select Blank Activity, which is basically a blank screen.
7. We finish the wizard.

With this, we will have our particular Hello world that always started programming when using a new API ( we also saw how to create a Hello World in AndroidStudio ). To run it, just have a real device connected or launch an emulator and click on the Run button (a green circle with the Play icon blank).

With this basic information, we end section today. Next week will enter fully into these 20 concepts that I think would help us to be much clearer how this organized structure Android API and therefore, we provide the things to be clear how to develop our applications.