My First Android Program
It’s pretty exciting to write about developing first program in Android. In our first program, we are going to have an image and label on the Window.
Its a simple traditional ‘Hello World’ program.
Let us begin with it by opening new android project in eclipse.
Launch eclipse, open new android project in either of the two ways:
File >> New >> Others >> Android >> Android Project
File >> New >> Android Project
Click next and provide project name which is going to be your Activity Class name, so make sure your project name must suite your functionality of the application.
After providing project name, click next and choose Android target device version. You have to choose your device’s installed Android version.
Click next and provide package name. Package name must follow naming convention since a particular device will have multiple packages which should not be ambiguous at run time. So follow below mentioned naming scheme:
All done, you have successfully created ‘New’ android project. Let’s modify the default layout and add controls to the application we just created to bring an image – Android logo and label – Hello Android at the center of the device’s window as we discussed earlier.
To begin with layout modification, we need to add an image – Android logo to the resources folder and add text ‘Hello Android’ in strings.xml.
Expand values folder >> Open strings.xml >> Look for String ‘hello’ >> Add text ‘Hello Android’ to ‘hello’ string element
Open main.xml under res/layout folder and replace the xml with the below xml which has one image and one label aligned centrally.
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center" android:orientation="vertical" > <ImageView android:id="@+id/imageView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@drawable/android_logo" /> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:gravity="center" android:text="@string/hello" /> </LinearLayout>
Open ‘Graphical layout’ of the main.xml, you could see the design of our application. Graphical layout allows you to design application UI just by doing simple drag and drop the controls.
That’s it, we need to run the program and check the output.
Google installs ‘Emulator’ along with the SDK installation. It’s upto you whether you want to run the application in Emulator or in your android device. I would prefer to run my apps on my device since most of the services like GPS, Google inbuilt services, bluetooth etc are not supported in Emulator but still application will run without any issues in Emulator if your app doesn’t involve any of the aforementioned services.
You must enable ‘USB debugging’ in your mobile settings so that it will be acting as target device when connected to your PC. And its simple to run your app in Mobile device.
Here is our most awaited output:
Download Source Code
Entire project is zipped and is available for download. Unzip the downloaded project and to import the project into eclipse, launch eclipse >> File >> Import.. >> Choose downloaded project (How to import android project in eclipse). If you just want to run the application in your mobile and see the output but don’t want to hit your head with source code, download application(apk) file and install it in your mobile device.Download Source Code Download Application(apk)
*apk in Android is the installation file simliar to exe in windows.
Keep me posted with your valuable feedback.
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