How to develop android appliation

This tutorial is very short and only for Android Beginners. In this tutorial I'll explain how to develop simple mobile android app and how to use TextView in android app.

Before starting this tutorial make sure you have knowledge about following concept:-
>> Basic Knowledge of Java concepts 
>> Basic knowledge of XML concepts

Prerequisites
 Before you start this tutorial, be sure you have your development environment set up. You need to :-
1. Download Android Studio.
2. After downloading Android Studio you will get an .exe(name: android-studio-bundle-          135.1641136.exe) file in the Download folder.
3. Run .exe file and install Android Studio.
4. Download the latest SDK tools and Platforms using the SDK Manager.
5. Now start Android Studio.
1.Create New Project

• Open File

• New Project 

• Choose Application Name

• Select the form factors your app will run on

• Select an activity

• Choose file name for your new file

Then click finish, 
After click finish your screen will look similar to that screen:-

2.Anatomy of an Android Application
First, note the various files that make up an Android project. Lets see what we have and their importance.

• Java:- Contains the .java source files for your project. In this tutorial, there is one file, MainActivity.java. The MainActivity.java file is the source file for your activity. You will write the code for your application in this file.
• AndroidManifest.xml:- This is the manifest file for your Android application. Here you specify the permissions needed by your application, as well as other features (such as intent-filters, receivers, etc. ).
• res:- This folder contains all the resources used in your application. It also contains a few other sub-folders: drawable-<resolution>, layout, and values.

3. Java

• MainActivity

package com.dev.myapplication;

import android.support.v7.app.ActionBarActivity;

import android.os.Bundle;

import android.view.Menu;

import android.view.MenuItem;

public class MainActivity extends ActionBarActivity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

    }

    @Override

    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.

        getMenuInflater().inflate(R.menu.menu_main, menu);

        return true;

    }

    @Override

    public boolean onOptionsItemSelected(MenuItem item) {

        // Handle action bar item clicks here. The action bar will

        // automatically handle clicks on the Home/Up button, so long

        // as you specify a parent activity in AndroidManifest.xml.

        int id = item.getItemId();

        //noinspection SimplifiableIfStatement

        if (id == R.id.action_settings) {

            return true;

        }

        return super.onOptionsItemSelected(item);

    }

}

4. res

• activity_main.xml

<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" android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <TextView android:text="@string/hello_world" android:layout_width="wrap_content"

        android:layout_height="wrap_content" />

</RelativeLayout>

Here we are using an TextView and Its attributes. Attributes help to define TextView height, width, id, text(what you want to show).

5. AndroidMenifest.xml

• AndroidMenifest.xml

<?xml version="1.0" encoding="utf-8"?>

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

    package="com.dev.myapplication" >

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name=".MainActivity"

            android:label="@string/app_name" >

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

    </application>

</manifest>

6. Values 

• string.xml

<?xml version="1.0" encoding="utf-8"?>

<resources>

    <string name="app_name">My Application</string>

    <string name="hello_world">Hello world!</string>

    <string name="action_settings">Settings</string>

</resources>

Here we define all the text values.

7. Now run your app

You can run your sample app in Android Virtual Device(Emulator) and also in your android device.

How to create Android Virtual Device(Emulator):-

• Click on AVD icon 

• Create virtual device

• Select hardware

• Select system image

• Verify configuration

• And, then click finish

How to use my android device as Emulator:- 

• Go to your settings
• Click on about phone 
• Then, click on "Build number" multiple time till the developer option available on your settings 
• Click on developer options and check USB debugging.

Note:- if you want to run your sample application in android device make sure you have connected you device through usb and all the necessary drivers are installed in your system.

After click on run you will get output screen:-

If you want change the output  from "Hello world" to "example_name" make some changes in your string.xml file.

• Go to values folder 
• Open string.xml

string.xml

 <?xml version="1.0" encoding="utf-8"?>

<resources>

    <string name="app_name">My Application</string>

    <string name="hello_world">Hello world!</string>

    <string name="action_settings">Settings</string>

</resources>

• Make some changes

<?xml version="1.0" encoding="utf-8"?>

<resources>

    <string name="app_name">My Application</string>

    <string name="hello_world">Example_Name</string>

    <string name="action_settings">Settings</string>

</resources>

Output:-

You can also download complete project with source code from here:-
Download .zip