AndroidWorld: My First Android Project

If you don't have an idea about the required software to create an android app, then visit my last post "Android Installation - SDK - AVD Manager"

To create first app and to grab the concept of android project, follow the steps mentioned below.

Just be with me....

Step 1: In Eclipse, Click on File --> New --> Project

Step 2: Android --> Android Application Project

Step 3: Here you need to provide lot many things.

Application Name: This name will be displayed, when an application is installed in device (For Example, Temple Run, Angry Bird)

Project Name: It's like a temporary Name. Project name will be displayed, as the name of project that we create in Eclipse. You can name it anything (may be same as Application Name).

Package Name: Here you need to be, bit careful. Every app in the play-store has a different package name. Keep two things in mind while providing package name. First, it has to be unique and the second, there must be one dot (.) in the package name.

Minimum Required SDK: Choose the lowest version of android that your application will support. Always prefer API level 8 to reach approximately 95% of the market.

Target SDK: Choose the Target Version, against which you want to test your application. You can prefer to latest version.

Compile With: Choose a target API to compile your code against, from your installed SDK. Always choose the highest API level.

Theme: Select a theme for your application.

Step 4: If you want to create an activity and choose your own launcher icon, then don't change the default selection. This project will be saved in workspace; you can change location, if you want. Now, Click on "Next" button.

Step 5: There are three options that android provides to set your Launcher Icon. You can keep an image of your own choice, by clicking on browser button.

The second choice is to set Clipart as your Icon. Click on choose button, where you find lot many Clip Art. You can select one of them.

The third or the last option is to keep text as your icon. Type whatever you would like as Text and then choose Font.

After selecting any of them, click on the Next button.

Step 6: You have five different choices to create an activity.

BlankActivity: Just creates a simple blank activity.

FullscreenActivity: Creates a new activity that shows and hides the system UI(status bar, system bar), and action bar, upon user interaction.

LoginActiity: Creates a new login activity, allowing users to enter a username / email address and password to login or register for your service.

MasterDetailFlow: This activity requires a minimum SDK version of at least 11. This master/detail flow activity creates two columns on tablets.

SettingActivity: Creates a new application settings activity.

Just choose the BlankActivity and click on Next button.

Step 7: Now, the last step of creating project.

Activity Name: The name of the Activity class to create.

Layout Name: The name of the layout to create for the activity.

Navigation Type: Choose the navigation type for your activity. The minimum SDK version has to be at least 11 to choose any of the navigation Type. So keep it "None" and click on Finish button.

Half Job is done now....

Once the project is created, it looks as shown below. We can see all files and folders of project in the "Project Explorer". The Graphical Layout of xml file (activity_myapp.xml) shows, how the default activity looks.

Apart from layout xml file, there are two other files that we have most interaction with.

(1) Java File in src folder

(2) strings.xml file in values folder.

MyApp.java

All the classes (or java file) of project are created in the src folder. Now, double click on the MyApp.java file to view it.

Strings.xml

Android allows you to create static attributes, e.g. Strings / Arrays / Colors. These attributes can be used in XML layout files or referred via Java Source Code. Open the res/values/string.xml file in Eclipse.

Click on Add button. Select String element and press ok button.

Type "display_info" in Name attribute and "This Is My First App" in Value attribute. The same way, add two more attributes here.

Name	Value
editText_info	Type Something Here
Btn_info	Cool

Switch to XML representation and check that the values are correct. We will use these attributes in layout xml file.

activity_myapp.xml

You have seen the default view of this xml file. Now, I am going to add some UI components in xml file. We can change the layout by drag and drop or editing the XML source code. You can switch between them anytime. Screenshot of Palette is shown here.

From Palette, drag & drop one Button and EditText into the layout.

Switch Graphical Layout to the XML file and compare your code, with the code shown below. If code is not same, then modify it.

<RelativeLayout 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"

tools:context=".MyApp" >

<EditText

android:id="@+id/editText1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentBottom="true"

android:layout_centerHorizontal="true"

android:layout_marginBottom="71dp"

android:ems="10"

android:inputType="text"

android:text="@string/editText_info"

android:textSize="20sp" />

<TextView

android:id="@+id/textView1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_above="@+id/button1"

android:layout_centerHorizontal="true"

android:layout_marginBottom="76dp"

android:text="@string/display_info"

android:textSize="20sp" />

<Button

android:id="@+id/button1"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_centerHorizontal="true"

android:layout_centerVertical="true"

android:text="@string/btn_info" />

</RelativeLayout>

If you have done job correctly, then your Graphical layout should look as this.

AndroidManifest.xml

Now, have a look over the most important file (AndroidManifest.xml) of project. You can consider it, as the controller of whole application. All Permissions, Activities, Services, and much other important information are described in this file.

Test Your APP:

To test your app; right click on the project, click on Run As --> Android Application, OR just press F11 to run your Application. However, if you have created multiple AVD of different SDK version then you can choose specific one.

To do that, right click on the project, choose Run As --> Run Configuration. This will open new window.

In Target tab of window, choose any AVD you like and then press Run button.