Get Started Developing for Android with Eclipse

Installing Eclipse and the Android SDK

The recommended environment for developing Android applications is Eclipse with the Android Development Toolkit (ADT) plugin installed. I’ll discuss the process here. If you need more detail, Google’s own developer pages do a good job of explaining the installation and configuration process.

• Download the Android SDK for your platform (Windows, Mac OS X, or Linux).
• Extract the downloaded file to somewhere on your hard drive (on Linux, I use /media/a).
• If you don’t already have Eclipse installed, download and install the Eclipse IDE for Java Developers package. For programming, Google recommends using Eclipse 3.5 (Galileo).
• Run Eclipse and choose Help->Install New Software.
• Click Add in the Available Software window.
• Enter Android Development Tools in the Name field, and https://dl-ssl.google.com/android/eclipse/ in the Location field.
• Click OK and check Developer Tools in the list of available software. This will install the Android Development Tools and DDMS, Android’s debugging tool.

Click Next and Finish to install the plugin. You’ll need to restart Eclipse once everything is installed.

• When Eclipse restarts, choose Window->Preferences and you should see Androidlisted in the categories.

You now need to tell Eclipse where you’ve installed the Android SDK. Click Androidand then Browse to select the location where you extracted the SDK files. For example,
/media/a/android-sdk-linux.

• Click OK to have Eclipse save the location of your SDK.

Android virtual device - Emulator

What is the Android Emulator?

The Android Development Tools (ADT) include an emulator to run an Android system. The emulator behaves like a real Android deviceIin most cases) and allows you to test your application without having a real device. 
You can configure the version of the Android system you would like to run, the size of the SD card, the screen resolution and other relevant settings. You can define several of them with different configurations.These devices are called Android Virtual Device and you can start several in parallel.

Emulator Shortcuts

The following shortcuts are useful for working with the emulator.

Alt+Enter Maximizes the emulator. Nice for demos.

Ctrl+F11 changes the orientation of the emulator.

F8 Turns network on / off.

Emulator Parameter

There are lots of parameters, we can set while creating android virtual device(AVD). 

The graphics of the emulator can use the native GPU of the computer. This makes the rendering in the emulator very fast. To enable this, add the GPU Emulation property to the device configuration and set it to true.

You can also set the Enabled flag for Snapshots. This will save the state of the emulator and will let it start much faster. Unfortunately currently native GPU rendering and Snapshots do not work together.

Get you start in Android programming

In this tutorial, we show you how to create a simple “hello world” Android project in Eclipse IDE + ADT plugin, and run it with Android Virtual Device (AVD). The Eclipse ADT plugin provided easy Android project creation and management, components drag and drop, auto-complete and many useful features to speed up your Android development cycles.

Create Android Project

In Eclipse, select “File -> New -> Project….”, “Android Project”, and input your application detail. Eclipse will create all the necessary Android project files and configuration.

Hello World

Locate the generated activity file, and modify a bit to output a string “Hello World”.

File : MainActivity.java

package com.learnsimply.helloworld;

import android.os.Bundle;

import android.app.Activity;

import android.view.Menu;

import android.widget.TextView;

public class MainActivity extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

TextView text = (TextView)findViewById(R.id.txtView);

text.setText("Hello World");

}

}

File : activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:tools="http://schemas.android.com/tools"

android:layout_width="match_parent"

android:layout_height="match_parent" >

<TextView

android:id="@+id/txtView"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

tools:context=".MainActivity" />

</LinearLayout>

Running Your Application

Now let’s try running the application in Eclipse. As this is the first run, Eclipse will ask what type of project you are working on:

• Choose Run->Run or press Ctrl+F11.
• Choose Android Application and click OK.

Eclipse will now try to run the application on an Android device. At the moment, though, you don’t have any Android devices running, so the run will fail and you’ll be asked to create a new Android Virtual Device (AVD).

Now create fresh android virtual device and test your application output.

Now Run your application and see output

Download source code from this link