Installing Android Studio & Setup | Android Tutorials in Hindi #1

Creating Our First Android App (with APK) | Android Tutorials in Hindi #2

Linear Layout & Relative Layout In Android | Android Tutorials in Hindi #3

Android activity & Activity Lifecycle | Android Tutorials in Hindi #4

Project 1: Tic Tac Toe Game Android Game Development | Android Tutorials in Hindi #5

Creating Photo Frame Application In Android: Exercise 1 | Android Tutorials in Hindi #6

Creating a Multi Screen Android  Application | Android Tutorials in Hindi #7

Creating a Navigation Drawer App with Hamburger Icon In Android | Android Tutorials in Hindi #8

Embedding Video with media controls in Android | Android Tutorials in Hindi #9

MediaPlayer & Handling Audio in Android | Android Tutorials in Hindi #10

Android SeekBar & its Methods | Android Tutorials in Hindi #11

Dynamic Photo Frame Application In Android Exercise 1: Solution | Android Tutorials in Hindi #12

Android ListViews & Array Adapters | Android Tutorials in Hindi #13

Multiplication Tables Application Project In Android | Android Tutorials in Hindi #14

CountDownTimer, Runnable & Handler in Android | Android Tutorials in Hindi #15

Performing Tasks in Background in Android | Android Tutorials in Hindi #16

What is an API & how to use API in Android | Android Tutorials in Hindi #17

Adding Volley Library dependency & Fake JSON API | Android Tutorials in Hindi #18

Retrieve & Parse JSON Data from Web URL in Android | Android Tutorials in Hindi #19

Multiplication Tables App on Seekbar Change: Exercise 2: Solution | Android Tutorials in Hindi #20

Android Exercise 3: Creating a User Display App | Android Tutorials in Hindi #21

Parsing Nested JSON Arrays & Objects | Android Tutorials in Hindi #22

Shared Preferences: Saving data to Android device | Android Tutorials in Hindi #23

Using a Database in Android | Android Tutorials in Hindi #24

SQLITE Android CRUD Database in Android | Android Tutorials in Hindi #25

SQLite Android CRUD: Adding Contacts to the Database | Android Tutorials in Hindi #26

SQLite Android CRUD: Fetching all Contacts | Android Tutorials in Hindi #27

SQLite Android CRUD: Updating Records | Android Tutorials in Hindi #28

SQLite Android CRUD: Deleting Records | Android Tutorials in Hindi #29

SQLite Android CRUD: Deleting Records | Android Tutorials in Hindi #30

SQLite Android CRUD: Adding ListView | Android Tutorials in Hindi #31

RecyclerView in Android | Android Tutorials in Hindi #32

Creating a RecyclerViewAdaper Class | Android Tutorials in Hindi #33

Adding OnClick Listener to RecyclerView | Android Tutorials in Hindi #34

Let's create a&nbsp;new project&nbsp;as &ldquo;BackgroundDemo&rdquo; by selecting an&nbsp;empty activity&nbsp;
<img src="https://cwh-full-next-space.fra1.digitaloceanspaces.com/videos/android-tutorials-in-hindi-16/16_1.webp" />
Now go to &ldquo;activity_main.xml&rdquo; and change the already existing text &ldquo;Hello World&rdquo; to &ldquo;Background Task&rdquo;&nbsp;&nbsp;
<img src="https://cwh-full-next-space.fra1.digitaloceanspaces.com/videos/android-tutorials-in-hindi-16/16_2.webp" />
In this video we will learn about how to do the tasks in background without&nbsp; altering the task going on the user interface. These task are known as Asynchronous task.&nbsp;
An asynchronous task is kind of background task.And the result of it is shown on the user interface.&nbsp;
Asynchronous task is mainly defined by 3 generic types&nbsp;&nbsp;called params , Progress and Result.&nbsp;
&nbsp;There are four steps(or methods) called to perform the Asynchronous tasks&nbsp;&nbsp;onPreExecute , doInBackground , onProgressUpdate and onPostExecute.
&nbsp;
In simple words Asynchronous tasks&nbsp;&nbsp;executes tasks in&nbsp;background&nbsp; without interrupting the UI threads.&nbsp;
Now we will take a button from the palette, drag and drop it on the screen, and will add the &ldquo;lelo&rdquo; method in the &ldquo;onClick&rdquo; attribute of the button. This &ldquo;lelo&rdquo; method will be executed when we will click this button.&nbsp;
We will further write its code in the &ldquo;MainActivity.java&rdquo;&nbsp; file.&nbsp;
<img src="https://cwh-full-next-space.fra1.digitaloceanspaces.com/videos/android-tutorials-in-hindi-16/16_3.webp" />
<pre class="language-java"><code>public void leLo(View view){ 

 Toast.makeText(this, "Selfie le li maine", Toast.LENGTH_SHORT).show(); 

 } </code></pre>
We will write the above function in the &rdquo;MainActivity.java&rdquo; file. A toast will pop up each time when we will click the button.&nbsp;
&nbsp;
Now we will make a class &ldquo;BG&rdquo; and this class will extend AsynchTask class.&nbsp;
The types within the angular braces of Asynchtask are three generic types params, progress, and result.&nbsp;
<pre class="language-java"><code>public class BG extends AsyncTask&lt;String, Void, String&gt;{ 
 @Override 
 protected void onPreExecute() { 
 super.onPreExecute(); 
 Log.d("HarryBG", "onPreExecute: ran"); 
 } 
 @Override 
 protected String doInBackground(String... urls) { 
 Log.d("HarryBG", "doInBackground: ran"); 
 } 
 @Override 
 protected void onPostExecute(String s) { 
 super.onPostExecute(s); 
 Log.d("HarryBG", "onPostExecute: ran"); 
 } 

 } </code></pre>
The above-written code is the basic implementation of the background task. Now we will write some code in the &ldquo;doInBackground&rdquo;&nbsp;&nbsp;method.&nbsp;
&nbsp;
The following code will read the data from the website URL and will store it in the &ldquo;result&rdquo; variable.&nbsp;
In the following code, the URL object is being created, the connection is being created and data is being read through the InputStream object. These are the basic implementations of the java language.&nbsp;
<pre class="language-java"><code>String result = ""; 

 URL url; 

 HttpURLConnection conn; 

 try { 

 url = new URL(urls[0]); 

 conn = (HttpURLConnection) url.openConnection(); 

 InputStream in = conn.getInputStream(); 

 InputStreamReader reader = new InputStreamReader(in); 

 int data = reader.read(); 

 while (data != -1) { 

 char current = (char) data; 

 result += current; 

 data = reader.read(); 

 } 

 } 

 catch(Exception e){ 

 e.printStackTrace(); 

 return "Something went wrong"; 

 } 

 return result; </code></pre>
now we just have to write a single line in the onPostExecute method to execute the result which was evaluated in the background task in doInbackground method&nbsp;&nbsp;
<pre class="language-java"><code>Log.d("HarryBG", s); </code></pre>
So basically these are the three methods which are used in performing background tasks. In this video, we have not shown the progress method as we have not updated any progress. we have only pre-executed the task using &ldquo;onPreExecute()&rdquo; and performed some tasks in the background using &ldquo;doInBackground()&rdquo; and printed the result of that task after execution using &ldquo;onPostExecute()&rdquo; method.&nbsp;
As the names indicates post execute, post means after so it means after execution. pre-execution means before executing and doInbackground means processing the task in the background &nbsp;
Now we will go to the &ldquo;AndroidManifest&rdquo; file to give our app the permission to use the internet &nbsp;
We have to write the following code in the &ldquo;AndroidManifest.xml&rdquo;&nbsp;file&nbsp;
<pre class="language-markup"><code>&lt;uses-permission android :name =&rdquo;android.permission.INTERNET&rdquo; &gt;&lt;uses-permission&gt; </code></pre>
<h4>Code as described/written in the video</h4>
<pre class="language-xml"><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;androidx.constraintlayout.widget.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=".MainActivity"&gt;

 &lt;TextView
 android:id="@+id/textView2"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_marginTop="64dp"
 android:text="Background Tasks"
 android:textSize="24sp"
 app:layout_constraintLeft_toLeftOf="parent"
 app:layout_constraintRight_toRightOf="parent"
 app:layout_constraintTop_toTopOf="parent" /&gt;

 &lt;Button
 android:id="@+id/button"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:layout_marginTop="68dp"
 android:onClick="leLo"
 android:text="Button"
 app:layout_constraintEnd_toEndOf="parent"
 app:layout_constraintStart_toStartOf="parent"
 app:layout_constraintTop_toBottomOf="@+id/textView2" /&gt;

&lt;/androidx.constraintlayout.widget.ConstraintLayout&gt;
</code></pre>
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<h4>Code as described/written in the video</h4>
<pre class="language-java"><code>package com.codewithharry.backgrounddemo;

import androidx.appcompat.app.AppCompatActivity;

import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;

import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class MainActivity extends AppCompatActivity {

 public class BG extends AsyncTask&lt;String, Void, String&gt;{
 @Override
 protected void onPreExecute() {
 super.onPreExecute();
 Log.d("HarryBG", "onPreExecute: ran");
 }

 @Override
 protected String doInBackground(String... urls) {
 Log.d("HarryBG", "doInBackground: ran");
 String result = "";
 URL url;
 HttpURLConnection conn;
 try {
 url = new URL(urls[0]);
 conn = (HttpURLConnection) url.openConnection();
 InputStream in = conn.getInputStream();
 InputStreamReader reader = new InputStreamReader(in);
 int data = reader.read();
 while (data != -1) {
 char current = (char) data;
 result += current;
 data = reader.read();
 }
 }
 catch(Exception e){
 e.printStackTrace();
 return "Something went wrong";
 }
 return result;


 }
 @Override
 protected void onPostExecute(String s) {
 super.onPostExecute(s);
 Log.d("HarryBG", "onPostExecute: ran");
 Log.d("HarryBG", s);

 }
 }

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
// BG myTask = new BG();
// myTask.execute("https://www.codewithharry.com/");

 final TextView textView = (TextView) findViewById(R.id.textView2);



 // Instantiate the RequestQueue.
 RequestQueue queue = Volley.newRequestQueue(this);
 String url ="http://www.google.com";

// Request a string response from the provided URL.
 StringRequest stringRequest = new StringRequest(Request.Method.GET, url,
 new Response.Listener&lt;String&gt;() {
 @Override
 public void onResponse(String response) {
 // Display the first 500 characters of the response string.
 textView.setText("Response is: "+ response.substring(0,500));
 }
 }, new Response.ErrorListener() {
 @Override
 public void onErrorResponse(VolleyError error) {
 textView.setText("That didn't work!");
 }
 });

// Add the request to the RequestQueue.
 queue.add(stringRequest);
 }
 public void leLo(View view){
 Toast.makeText(this, "Selfie le li maine", Toast.LENGTH_SHORT).show();
 }
}

</code></pre>