❮ Previous Next ❯

Hello World Example

Let us start actual programming with Android Framework. Before you start writing your first example using Android SDK, you have to make sure that you have set-up your Android development environment properly.

Create Android Application

The first step is to create a simple Android Application using Android studio. When you click on Android studio icon, it will show screen as shown below.


android1

You can start your application development by calling start a new android studio project. In a new installation frame should ask Application name, Package Information and location of the Project.


android2

After entered application name, it going to be called select the form factors your application runs on, here need to specify Minimum SDK, in our tutorial, I have declared as API24: Android 7.0(Nougat), But  you can declare according to Android devices.


android3

The next level of installation should contain selecting the activity to mobile, it specifies the default layout for Applications.

 


android4

At the final stage it going to be  Finish .


android5

android6
Sr.No. Folder, File & Description
Java This contains the .java source files for your project. By default, it includes an MainActivity.java source file having an activity class that runs when your app is launched using the app icon.
2 res/drawable-hdpi
This is a directory for drawable objects that are designed for high-density screens.
3 res/layout
This is a directory for files that define your app's user interface.
4 res/values
This is a directory for other various XML files that contain a collection of resources, such as strings and colours definitions.
5 AndroidManifest.xml
This is the manifest file which describes the fundamental characteristics of the app and defines each of its components.
6 Build.gradle
This is an auto generated file which contains compileSdkVersion, buildToolsVersion, applicationId, minSdkVersion, targetSdkVersion, versionCode and versionName

The Layout File

The activity_main.xml is a layout file available in res/layout directory, that is referenced by your application when building its interface. You will modify this file very frequently to change the layout of your application. For your "Hello World!" application, this file will have following content related to default layout .


android7

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
   
xmlns:app="http://schemas.android.com/apk/res-auto"
   
xmlns:tools="http://schemas.android.com/tools"
   
android:layout_width="match_parent"
   
android:layout_height="match_parent"
   
tools:context="com.example.krushna.myapplication.MainActivity">
    <TextView
       
android:layout_width="wrap_content"
       
android:layout_height="wrap_content"
       
android:text="Hello World!"
       
app:layout_constraintBottom_toBottomOf="parent"
       
app:layout_constraintLeft_toLeftOf="parent"
       
app:layout_constraintRight_toRightOf="parent"
       
app:layout_constraintTop_toTopOf="parent" />

</android.support.constraint.ConstraintLayout>

 


The Main Activity File

The main activity code is a Java file MainActivity.java. This is the actual application file which ultimately gets converted to a Dalvik executable and runs your application. Following is the default code generated by the application wizard for “Hello World!” Application.


android8
package com.example.krushna.myapplication;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

 

 

How to Run the Application

Let's try to run our Hello World! application we just created. I assume you had created your AVD while doing environment set-up. To run the app from Android studio, open one of your project's activity files and click Run 
android9
 icon from the tool bar. Android studio installs the app on your AVD and starts it and if everything is fine with your set-up and application, it will display following Emulator window.

 


android10
android11

Congratulations!!! You've now completed your first Android application with some basic functionality. and now just keep following step by step to become a great Android Developer. THANKYOU


❮ Previous Next ❯



Follow Us




  Tutorials

Popular Links

Contact Us

address Plot No-741,2ND Floor
Opp. Bhagabati Temple,Jayadev Vihar
      Bhubaneswar-751013
      Email: info@silantechnology.com
      Phone: 0674-2361252
address
39877, sundale dr, apt#101, Fremont, California 94538, USA
       Phone: +1(262)388-7619

facebook twitter google linked in

© 2018 Silan Technology. All Rights Reserved