Google Android platform is fast becoming one of the most popular development platforms for your mobile devices. As more people are using their mobile devices for things normally done from a laptop or desktop means your customers or other internal employees such as sales people will soon start expecting you to offer them the capability to communicate with your data and business logic through mobile devices.
Setting Up Your PC for Android Development
Things you need in your PC to develop an Android application. The best part, you can download them for free:
1) Java Development Kit (JDK) of 1.5 or higher
Tip: You can skip this step and go to Step 3. When the Android Installer starts it will check your system for Java SDK and if not found will give you the link to install the Java SDK. After that it will install the Android SDK. Then go and take care of Eclipse in Step 2.
2) Eclipse Java Developer IDE (Eclipse Ganymede or above installation)
3) Android SDK (Software Development kit)
4) Eclipse plugin for Android Development
- Use URL https://dl-ssl.google.com/android/eclipse/ to access the Android Development Tools Plugin (ADT)
5) Android Virtual Device
- Its just a simulator so that you don't have to have a Android Phone to TEST plus its easy to do it this way for development.
Step by Step to get Hello World ! running on AndroidNote: You don't have to do all the steps if you already have Java SDK or Eclipse setup on your computer.
Setup Java Development KitYou may already have Java installed on your computer but it may be just the JRE (Java Runtime Environment). You need to make sure that you have JDK (Java Development Kit) version 1.5 or higher. You can go to the Oracle website(http://www.oracle.com) and get it. Here is a direct link to the JDK 1.6 version.
Setup EclipseEclipse is a multi-language software development environment comprising an integrated development environment (IDE) and an extensible plug-in system. It is written mostly in Java and can be used to develop applications in Java and, by means of various plug-ins, other programming languages including Ada, C, C++, COBOL, Perl, PHP, Python, R. Ruby (including Ruby on Rails framework), Scala, Clojure, and Scheme. The IDE is often called Eclipse ADT (Ada Development Toolkit) for Ada, Eclipse CDT for C/C++, Eclipse JDT for Java, and Eclipse PDT for PHP.
You can go to http://www.eclipse.org to download or
Here is the direct link
Eclipse is easy to install
Once you have unzipped the previously downloaded file, you will see a folder named eclipse. In that folder you will find the eclipse application (a big blue dot). We recommend you create a shortcut on the desktop to simplify the launching of eclipse. Notice that unlike Java, Eclipse does not have an installation process. Once you have unzipped the file you are done.
After being launched Eclipse will ask you to specify the workspace to use. The workspace is a folder used by eclipse to keep all your work. Specify an already existing folder or accept the default provided by Eclipse or provide a new folder.
Download the Android SDK
Here is the direct link to the Android SDK Installer
Please note the SDK starter package is not a full development environment—it includes only the core SDK Tools, which you can use to download the rest of the SDK components (such as the latest Android platform).
For more information about installing the Android SDK click here
Install Eclipse plugin for Android Development
Start Eclipse if has not been started. Now go to Help > Install New Software
Name = ADT Plugin
Location = https://dl-ssl.google.com/android/eclipse/
Eclipse is now setup for Android developmentYou should see the the Android SDK and AVD Manager under Window menu.
Time to create the Android Virtual Device (AVD)
AVD is a Android Phone emulator so that you can TEST your applications without having an actual Android Phone. To deploy applications in the emulator, you need to define an Android Virtual Device (AVD) that defines the characteristics of your device.
Select Virtual Devices in the left panel then Click New.
Type the name of the AVD, such as "MyDroid3.0".
Choose a target.
You can ignore the rest of the fields for now. Click Create AVD.
Create Hello World Android Project
From Eclipse, select File > New > Project.
Select "Android Project" and click Next.
Project name: Android Tutorials
Application name: My first Android Program, Hello World
Package name: com.as400samplecode (or your own private namespace)
Create Activity: HelloWorld
Here is a description of each field:
This is the Eclipse Project name — the name of the directory that will contain the project files.
This is the human-readable title for your application — the name that will appear on the Android device.
This is the package namespace
This is the name for the class stub that will be generated by the plugin. This will be a subclass of Android's Activity class. An Activity is simply a class that can run and do work. It can create a UI if it chooses, but it doesn't need to. As the checkbox suggests, this is optional, but an Activity is almost always used as the basis for an application.
Analyzing the Android Hello World ProjectOnce the Hello World project is created you will the following in your Eclipse Package Explorer.
src > com.as400samplecode > HelloWorld.java
res > layout > main.xml
res > values > string.xml
Let's run the application. We will come back and play with these later ....
Run the Hello World Application
The Eclipse plugin makes it easy to run your applications:
Select the project "Android Tutorials"
Select Run > Run As.
Select "Android Application".
The Eclipse plugin automatically creates a new run configuration for your project and then launches the Android Emulator. Depending on your environment, the Android emulator might take several minutes to boot fully, so please be patient. When the emulator is booted, the Eclipse plugin installs your application and launches the default Activity. You should now see something like this (depends on what version you chose for the AVD emulator).
Modify our Hello World ProgramGo to the strings.xml file under src > values. It should look like this.
<?xml version="1.0" encoding="utf-8"?> <resources> <string name="hello">Hello World, HelloWorld!</string> <string name="app_name">My first Android Program, Hello World</string> </resources>
These are the values getting displayed on the AVD emulator and gets mapped to the layout in main.xml
<TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="@string/hello"/>
So go ahead and change this values and see the results ! Follow the same steps to run the application as above but this time it will not take that much time as the AVD was already up and running.
Alternate way to modify the Hello World applicationYou can edit the HelloWorld.java directly as directed below
Replace the following code:
With the code given below
TextView textView = new TextView(this);
Tip: In case you are getting errors is you need to import the missing java packages. An easy way to add import packages to your project is to press Ctrl-Shift-O (Cmd-Shift-O, on Mac). This is an Eclipse shortcut that identifies missing packages based on your code and adds them for you.
Here you are not using the layout main.xml anymore. I am not a great fan of this. You should always use Model View Controller (MVC) architecture when available as its easy to maintain applications that way and different skillset can work on different components.
All done with Hello World, you can mess around with the main.xml and strings.xml file !
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