Android MySQL Tutorial to Perform Basic CRUD Operation

Hello friends, Here is another Android MySQL Tutorial, in this post we will learn the basic CRUD operation in MySQL database from Android Application. So without wasting time lets start our Android MySQL Tutorial.

Table of Contents

1 What is CRUD?
2 Why PHP and MySQL and Why Not SQLite?
- 2.1 Do we have only PHP and MySQL for this?
3 Building Web APIs
- 3.1 Creating Database
- 3.2 Creating PHP Project
4 Want to Explore Building RESTful APIs?
5 Android MySQL Tutorial
6 Android MySQL Tutorial – Source Code Download

What is CRUD?

I guess many of you already know that what is CRUD. But if anyone don’t know, CRUD is an Acronym for the Basic Database Operations. In any database we do the following basic operations.

Creating a Record -> In the database we insert a record.
Reading Stored Records -> No point of saving data when we can’t read it back 😛 (LOL). So the second operation is reading the stored data back.
Updating Stored Records -> We may also need to update the existing data. So the third operation is update.
Deleting Records -> Lastly we may also need to delete the existing data from the database.

So basically in any database we perform the above mentioned operations. In this tutorial I am going to use MySQL and PHP.

Why PHP and MySQL and Why Not SQLite?

Android gives us a feature of SQLite to use as the RDBMS for our app. But we can’t use SQLite only if we are building an app. This is because we need a centralize server. SQLite is local for every device so if a user is using your application you will not be able manage your users if it is only in SQLite. That is why we need a centralize database where we can store our app data.

If you want to learn about the SQLite using the Latest Architecture Component ROOM. Then here is a complete FREE COURSE for Android Room Database.

Do we have only PHP and MySQL for this?

Obviously NO? You can use any server side scripting language or database application. I am using here PHP and MySQL because it is easily available and I already know it. 😛 (LOL) But if you are an expert in Python or JAVA or NodeJS or basically any other technology then you can go with it. It will change only the server side coding. Android part will always be the same.

Building Web APIs

The first step is building the required Web APIs. This is because from the android application, to communicate with our web server we need an interface called API.

So our android device will send a request to our API, then our API will perform the requested task and it will give us the response related to the task. You can see the below diagram for more clarification.

The response that the web server gives should be in a standard structure, so that in our android side we can easily parse and get the information from the structure. For this everyone now uses JSON. If you heard this term for the first time then you should consider watching this 7 minute quick JSON tutorial.

I guess you got a basic idea about the task that we are going to do in this tutorial.

Creating Database

It is obvious that we need a database first 😛 . So here I am using XAMPP (You can go with wamp or lamp as well). So first create the following database.

So open localhost/phpmyadmin and run the following query to create the above table.

-- created by Belal Khan

-- website: www.simplifiedcoding.net

-- tables

-- Table: heroes

CREATE TABLE heroes (

id int NOT NULL AUTO_INCREMENT,

name varchar(200) NOT NULL,

realname varchar(200) NOT NULL,

rating int NOT NULL,

teamaffiliation varchar(100) NOT NULL,

CONSTRAINT heroes_pk PRIMARY KEY (id)

);

-- End of file.

Creating PHP Project

Now to perform the Database Operations we will create a PHP Project.

So inside htdocs (c:/xampp/htdocs) create a new folder (You can also use an IDE like PHP Storm to create project but remember create the project inside c:/xampp/htdocs only).
I have given the name HeroApi to my project. You can give any name. But I would say give the same name or else you may lead up to some errors following the post if you are a newbie.
Inside the project create two more folders named includes and Api. You can see the below screenshot for the directory structure that I am using. (I am using Sublime Text for coding server part).

You see we have four php files (3 inside includes and 1 inside v1). So you create these files as well.

Project Structure

So we have the following things in our PHP project.
- includes
  - Constants.php: In this file we will define all the required constants e.g., database name, username, password etc.
  - DbConnect.php: This fill will contain a class where we will connect to our MySQL database.
  - DbOperation.php: The actual CRUD operation is performed inside this file.
- v1
  - Api.php: This is our API, we will send request to this file only from the android side. And this file will handle all the API calls.

Defining Constants

First come inside the file Constants.php and write the following code.

<?php

* Created by Belal Khan

* website: www.simplifiedcoding.net

define('DB_HOST', 'localhost');

define('DB_USER', 'root');

define('DB_PASS', '');

define('DB_NAME', 'android');

Connecting to Database

Now inside DbConnect.php write the following code. I have explained the code using comments.

<?php

* Created by Belal Khan

* website: www.simplifiedcoding.net

//Class DbConnect

class DbConnect

{

//Variable to store database link

private $con;

//Class constructor

function __construct()

{

}

//This method will connect to the database

function connect()

{

//Including the constants.php file to get the database constants

include_once dirname(__FILE__) . '/Constants.php';

//connecting to mysql database

$this->con = new mysqli(DB_HOST, DB_USER, DB_PASS, DB_NAME);

//Checking if any error occured while connecting

if (mysqli_connect_errno()) {

echo "Failed to connect to MySQL: " . mysqli_connect_error();

}

//finally returning the connection link

return $this->con;

}

Performing Database Operations

Now we will do the CRUD operation inside the DbOperation.php file.

<?php

class DbOperation

{

//Database connection link

private $con;

//Class constructor

function __construct()

{

//Getting the DbConnect.php file

require_once dirname(__FILE__) . '/DbConnect.php';

//Creating a DbConnect object to connect to the database

$db = new DbConnect();

//Initializing our connection link of this class

//by calling the method connect of DbConnect class

$this->con = $db->connect();

}

* The create operation

* When this method is called a new record is created in the database

function createHero($name, $realname, $rating, $teamaffiliation){

$stmt = $this->con->prepare("INSERT INTO heroes (name, realname, rating, teamaffiliation) VALUES (?, ?, ?, ?)");

$stmt->bind_param("ssis", $name, $realname, $rating, $teamaffiliation);

if($stmt->execute())

return true;

return false;

}

* The read operation

* When this method is called it is returning all the existing record of the database

function getHeroes(){

$stmt = $this->con->prepare("SELECT id, name, realname, rating, teamaffiliation FROM heroes");

$stmt->execute();

$stmt->bind_result($id, $name, $realname, $rating, $teamaffiliation);

$heroes = array();

while($stmt->fetch()){

$hero = array();

$hero['id'] = $id;

$hero['name'] = $name;

$hero['realname'] = $realname;

$hero['rating'] = $rating;

$hero['teamaffiliation'] = $teamaffiliation;

array_push($heroes, $hero);

}

return $heroes;

}

* The update operation

* When this method is called the record with the given id is updated with the new given values

function updateHero($id, $name, $realname, $rating, $teamaffiliation){

$stmt = $this->con->prepare("UPDATE heroes SET name = ?, realname = ?, rating = ?, teamaffiliation = ? WHERE id = ?");

$stmt->bind_param("ssisi", $name, $realname, $rating, $teamaffiliation, $id);

if($stmt->execute())

return true;

return false;

}

* The delete operation

* When this method is called record is deleted for the given id

function deleteHero($id){

$stmt = $this->con->prepare("DELETE FROM heroes WHERE id = ? ");

$stmt->bind_param("i", $id);

if($stmt->execute())

return true;

return false;

}

Handling API Calls

Now here come the main part, which is handling the API calls. So come inside the Api.php which is inside the v1 folder.

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<?php

//getting the dboperation class

require_once '../includes/DbOperation.php';

//function validating all the paramters are available

//we will pass the required parameters to this function

function isTheseParametersAvailable($params){

//assuming all parameters are available

$available = true;

$missingparams = "";

foreach($params as $param){

if(!isset($_POST[$param]) || strlen($_POST[$param])<=0){

$available = false;

$missingparams = $missingparams . ", " . $param;

}

//if parameters are missing

if(!$available){

$response = array();

$response['error'] = true;

$response['message'] = 'Parameters ' . substr($missingparams, 1, strlen($missingparams)) . ' missing';

//displaying error

echo json_encode($response);

//stopping further execution

die();

}

//an array to display response

$response = array();

//if it is an api call

//that means a get parameter named api call is set in the URL

//and with this parameter we are concluding that it is an api call

if(isset($_GET['apicall'])){

switch($_GET['apicall']){

//the CREATE operation

//if the api call value is 'createhero'

//we will create a record in the database

case 'createhero':

//first check the parameters required for this request are available or not

isTheseParametersAvailable(array('name','realname','rating','teamaffiliation'));

//creating a new dboperation object

$db = new DbOperation();

//creating a new record in the database

$result = $db->createHero(

$_POST['name'],

$_POST['realname'],

$_POST['rating'],

$_POST['teamaffiliation']

);

//if the record is created adding success to response

if($result){

//record is created means there is no error

$response['error'] = false;

//in message we have a success message

$response['message'] = 'Hero addedd successfully';

//and we are getting all the heroes from the database in the response

$response['heroes'] = $db->getHeroes();

}else{

//if record is not added that means there is an error

$response['error'] = true;

//and we have the error message

$response['message'] = 'Some error occurred please try again';

}

break;

//the READ operation

//if the call is getheroes

case 'getheroes':

$db = new DbOperation();

$response['error'] = false;

$response['message'] = 'Request successfully completed';

$response['heroes'] = $db->getHeroes();

break;

//the UPDATE operation

case 'updatehero':

isTheseParametersAvailable(array('id','name','realname','rating','teamaffiliation'));

$db = new DbOperation();

$result = $db->updateHero(

$_POST['id'],

$_POST['name'],

$_POST['realname'],

$_POST['rating'],

$_POST['teamaffiliation']

);

if($result){

$response['error'] = false;

$response['message'] = 'Hero updated successfully';

$response['heroes'] = $db->getHeroes();

}else{

$response['error'] = true;

$response['message'] = 'Some error occurred please try again';

}

break;

//the delete operation

case 'deletehero':

//for the delete operation we are getting a GET parameter from the url having the id of the record to be deleted

if(isset($_GET['id'])){

$db = new DbOperation();

if($db->deleteHero($_GET['id'])){

$response['error'] = false;

$response['message'] = 'Hero deleted successfully';

$response['heroes'] = $db->getHeroes();

}else{

$response['error'] = true;

$response['message'] = 'Some error occurred please try again';

}

}else{

$response['error'] = true;

$response['message'] = 'Nothing to delete, provide an id please';

}

break;

}

}else{

//if it is not api call

//pushing appropriate values to response array

$response['error'] = true;

$response['message'] = 'Invalid API Call';

}

//displaying the response in json structure

echo json_encode($response);

Now lets test the APIs.

Testing the API Calls

For testing the API Calls here I am using POSTMAN. It is a REST API Client for Google Chrome.

Create Operation

Read Operation

Update Operation

Delete Operation

You see all the operations are working absolutely fine. Now we can move ahead in creating our Android Project. But before moving to android side below you can see our API URLs.

Finalizing API Calls

The below table displays our API URLs with the Parameter and Method. Remember using localhost in android side will not work. You need to find your IP. I have my IP in the below table, but in your case you need to find yours. So if you are using a windows you can use ipconfig command to find IP and for MAC or Linux use the ifconfig command. For more details you can visit this tutorial.

POST: http://192.168.101.1/HeroApi/v1/Api.php?apicall=createhero
GET: http://192.168.101.1/HeroApi/v1/Api.php?apicall=getheroes
POST: http://192.168.101.1/HeroApi/v1/Api.php?apicall=updatehero
GET: http://192.168.101.1/HeroApi/v1/Api.php?apicall=deletehero&id=idvalue

Want to Explore Building RESTful APIs?

Here we built a very basic API that demonstrates the CRUD operation. But in real world scenarios we use FRAMEWORKS to make the API creating easy and structured. If you want to dig a bit more about building RESTful APIs. Then you should check the following course. It is absolutely FREE.

Android MySQL Tutorial

We have our Web Services, and now we can build the android application. So lets start.

Creating a new Project

Create a new Android Studio Project. Here I have created a project named MyHeroApp.
Once your project is loaded inside the package we will create all the helper classes that is required for thie project.

Creating Helper Classes

Class To Store API URLs

First create a class named Api.java and write the following code.

package net.simplifiedlearning.myheroapp;

/**

* Created by Belal on 9/9/2017.

public class Api {

private static final String ROOT_URL = "http://192.168.101.1/HeroApi/v1/Api.php?apicall=";

public static final String URL_CREATE_HERO = ROOT_URL + "createhero";

public static final String URL_READ_HEROES = ROOT_URL + "getheroes";

public static final String URL_UPDATE_HERO = ROOT_URL + "updatehero";

public static final String URL_DELETE_HERO = ROOT_URL + "deletehero&id=";

}

Hero Model Class

We also need a model class for our Hero. So create a class named Hero.java and write the following code. It will have only properties, constructor and getters.

package net.simplifiedlearning.myheroapp;

import java.io.Serializable;

/**

* Created by Belal on 9/9/2017.

class Hero {

private int id;

private String name, realname;

private int rating;

private String teamaffiliation;

public Hero(int id, String name, String realname, int rating, String teamaffiliation) {

this.id = id;

this.name = name;

this.realname = realname;

this.rating = rating;

this.teamaffiliation = teamaffiliation;

}

public int getId() {

return id;

}

public String getName() {

return name;

}

public String getRealname() {

return realname;

}

public int getRating() {

return rating;

}

public String getTeamaffiliation() {

return teamaffiliation;

}

Request Handler

We need to send GET and POST request to our API URLs, and for this I am creating a new class that will perform these tasks. So create a new class named RequestHandler.java and write the following code.

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package net.simplifiedlearning.myheroapp;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.InputStreamReader;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.UnsupportedEncodingException;

import java.net.HttpURLConnection;

import java.net.URL;

import java.net.URLEncoder;

import java.util.HashMap;

import java.util.Map;

import javax.net.ssl.HttpsURLConnection;

/**

* Created by Belal on 9/9/2017.

public class RequestHandler {

//Method to send httpPostRequest

//This method is taking two arguments

//First argument is the URL of the script to which we will send the request

//Other is an HashMap with name value pairs containing the data to be send with the request

public String sendPostRequest(String requestURL,

HashMap<String, String> postDataParams) {

//Creating a URL

URL url;

//StringBuilder object to store the message retrieved from the server

StringBuilder sb = new StringBuilder();

try {

//Initializing Url

url = new URL(requestURL);

//Creating an httmlurl connection

HttpURLConnection conn = (HttpURLConnection) url.openConnection();

//Configuring connection properties

conn.setReadTimeout(15000);

conn.setConnectTimeout(15000);

conn.setRequestMethod("POST");

conn.setDoInput(true);

conn.setDoOutput(true);

//Creating an output stream

OutputStream os = conn.getOutputStream();

//Writing parameters to the request

//We are using a method getPostDataString which is defined below

BufferedWriter writer = new BufferedWriter(

new OutputStreamWriter(os, "UTF-8"));

writer.write(getPostDataString(postDataParams));

writer.flush();

writer.close();

os.close();

int responseCode = conn.getResponseCode();

if (responseCode == HttpsURLConnection.HTTP_OK) {

BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));

sb = new StringBuilder();

String response;

//Reading server response

while ((response = br.readLine()) != null) {

sb.append(response);

}

} catch (Exception e) {

e.printStackTrace();

}

return sb.toString();

}

public String sendGetRequest(String requestURL) {

StringBuilder sb = new StringBuilder();

try {

URL url = new URL(requestURL);

HttpURLConnection con = (HttpURLConnection) url.openConnection();

BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));

String s;

while ((s = bufferedReader.readLine()) != null) {

sb.append(s + "\n");

}

} catch (Exception e) {

}

return sb.toString();

}

private String getPostDataString(HashMap<String, String> params) throws UnsupportedEncodingException {

StringBuilder result = new StringBuilder();

boolean first = true;

for (Map.Entry<String, String> entry : params.entrySet()) {

if (first)

first = false;

else

result.append("&");

result.append(URLEncoder.encode(entry.getKey(), "UTF-8"));

result.append("=");

result.append(URLEncoder.encode(entry.getValue(), "UTF-8"));

}

return result.toString();

}

Defining Internet Permission in AndroidManifest

As we need to perform network request from our Application, we need to define internet permission for this. And because we are working with localhost our APIs are not secured i.e. we have HTTP URLs and not HTTPS for our APIs.
And by default your application are restricted to communicate with non HTTPS URLs (For security reasons). So you need to explicitly define that your app should be allowed to communicate with HTTP URLs. And to do this you need to add usesCleartextTraffic=”true” inside your opening application tag. (See the below code that is AndroidManifest.xml for my project.).

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

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

package="net.simplifiedlearning.myheroapp">

<uses-permission android:name="android.permission.INTERNET" />

<application

android:usesCleartextTraffic="true"

android:allowBackup="true"

android:icon="@mipmap/ic_launcher"

android:label="@string/app_name"

android:roundIcon="@mipmap/ic_launcher_round"

android:supportsRtl="true"

android:theme="@style/AppTheme">

<intent-filter>

</intent-filter>

</activity>

</application>

</manifest>

Designing User Interface

The below image shows how our final application will look.

So we need to design the above mentioned things. I have already designed the activity_main.xml so you can directly use the below code.

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

<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="net.simplifiedlearning.myheroapp.MainActivity">

<LinearLayout

android:id="@+id/linearLayout"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_alignParentTop="true"

android:orientation="vertical"

android:padding="16dp">

<EditText

android:id="@+id/editTextHeroId"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:visibility="gone" />

<EditText

android:id="@+id/editTextName"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginBottom="8dp"

android:layout_marginTop="8dp"

android:hint="Name" />

<EditText

android:id="@+id/editTextRealname"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginBottom="8dp"

android:layout_marginTop="8dp"

android:hint="Realname" />

<RatingBar

android:id="@+id/ratingBar"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:numStars="5"

android:stepSize="1" />

<Spinner

android:id="@+id/spinnerTeamAffiliation"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_marginBottom="8dp"

android:layout_marginTop="8dp"

android:entries="@array/teams" />

<Button

android:id="@+id/buttonAddUpdate"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="Add" />

</LinearLayout>

<ListView

android:id="@+id/listViewHeroes"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:layout_below="@id/linearLayout" />

<ProgressBar

android:id="@+id/progressBar"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_centerHorizontal="true"

android:layout_centerVertical="true"

android:visibility="gone" />

</RelativeLayout>

For the spinner I have used static entries using xml array. So you also need to create this array. For this go inside values -> strings.xml

<string name="app_name">Android MySQL CRUD</string>

<item>Avengers</item>

<item>Justice League</item>

<item>Fantastic Four</item>

</array>

</resources>

Thats it for the User Interface part.
Now lets perform the CRUD operations in our MySQL database.

Class to Perform Network Request

The point is we cannot directly perform a network request in the application’s main thread. So for this we need an AsyncTask to perform the task in a separate thread. Hence we will create an inner class inside MainActivity.java.

//inner class to perform network request extending an AsyncTask

private class PerformNetworkRequest extends AsyncTask<Void, Void, String> {

//the url where we need to send the request

String url;

//the parameters

HashMap<String, String> params;

//the request code to define whether it is a GET or POST

int requestCode;

//constructor to initialize values

PerformNetworkRequest(String url, HashMap<String, String> params, int requestCode) {

this.url = url;

this.params = params;

this.requestCode = requestCode;

}

//when the task started displaying a progressbar

@Override

protected void onPreExecute() {

super.onPreExecute();

progressBar.setVisibility(View.VISIBLE);

}

//this method will give the response from the request

@Override

protected void onPostExecute(String s) {

super.onPostExecute(s);

progressBar.setVisibility(GONE);

try {

JSONObject object = new JSONObject(s);

if (!object.getBoolean("error")) {

Toast.makeText(getApplicationContext(), object.getString("message"), Toast.LENGTH_SHORT).show();

//refreshing the herolist after every operation

//so we get an updated list

//we will create this method right now it is commented

//because we haven't created it yet

//refreshHeroList(object.getJSONArray("heroes"));

}

} catch (JSONException e) {

e.printStackTrace();

}

//the network operation will be performed in background

@Override

protected String doInBackground(Void... voids) {

RequestHandler requestHandler = new RequestHandler();

if (requestCode == CODE_POST_REQUEST)

return requestHandler.sendPostRequest(url, params);

if (requestCode == CODE_GET_REQUEST)

return requestHandler.sendGetRequest(url);

return null;

}

Create Operation

Now lets save a new hero to our database. First we will define all the views. And we will attach a clicklistener to the button and inside the click event we will call the method to create a new record in the database.

public class MainActivity extends AppCompatActivity {

private static final int CODE_GET_REQUEST = 1024;

private static final int CODE_POST_REQUEST = 1025;

//defining views

EditText editTextHeroId, editTextName, editTextRealname;

RatingBar ratingBar;

Spinner spinnerTeam;

ProgressBar progressBar;

ListView listView;

Button buttonAddUpdate;

//we will use this list to display hero in listview

List<Hero> heroList;

//as the same button is used for create and update

//we need to track whether it is an update or create operation

//for this we have this boolean

boolean isUpdating = false;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

editTextHeroId = (EditText) findViewById(R.id.editTextHeroId);

editTextName = (EditText) findViewById(R.id.editTextName);

editTextRealname = (EditText) findViewById(R.id.editTextRealname);

ratingBar = (RatingBar) findViewById(R.id.ratingBar);

spinnerTeam = (Spinner) findViewById(R.id.spinnerTeamAffiliation);

buttonAddUpdate = (Button) findViewById(R.id.buttonAddUpdate);

progressBar = (ProgressBar) findViewById(R.id.progressBar);

listView = (ListView) findViewById(R.id.listViewHeroes);

heroList = new ArrayList<>();

buttonAddUpdate.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

//if it is updating

if (isUpdating) {

//calling the method update hero

//method is commented becuase it is not yet created

//updateHero();

} else {

//if it is not updating

//that means it is creating

//so calling the method create hero

createHero();

}

});

//calling the method read heroes to read existing heros from the database

//method is commented because it is not yet created

//readHeroes();

}

Now we need to create the method createHero().

private void createHero() {

String name = editTextName.getText().toString().trim();

String realname = editTextRealname.getText().toString().trim();

int rating = (int) ratingBar.getRating();

String team = spinnerTeam.getSelectedItem().toString();

//validating the inputs

if (TextUtils.isEmpty(name)) {

editTextName.setError("Please enter name");

editTextName.requestFocus();

return;

}

if (TextUtils.isEmpty(realname)) {

editTextRealname.setError("Please enter real name");

editTextRealname.requestFocus();

return;

}

//if validation passes

HashMap<String, String> params = new HashMap<>();

params.put("name", name);

params.put("realname", realname);

params.put("rating", String.valueOf(rating));

params.put("teamaffiliation", team);

//Calling the create hero API

PerformNetworkRequest request = new PerformNetworkRequest(Api.URL_CREATE_HERO, params, CODE_POST_REQUEST);

request.execute();

}

Now run the application and try adding a new hero.

android mysql tutorial - create operation — Android MySQL – Create Operation

Its working fine, you can check the database as well. Now lets move to the read operation.

Read Operation

We will display all the heroes from the database in a ListView, the ListView also have the Update and Delete Button.
So for this first we will create a custom Layout for our ListView.

List Layout

Create a layout resource file named layout_hero_list.xml.

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

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

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="horizontal"

android:padding="8dp">

<TextView

android:id="@+id/textViewName"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentLeft="true"

android:layout_weight="8"

android:text="Captain America"

android:textAppearance="@style/Base.TextAppearance.AppCompat.Medium" />

<TextView

android:textStyle="bold"

android:id="@+id/textViewUpdate"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignBottom="@+id/textViewDelete"

android:layout_toLeftOf="@+id/textViewDelete"

android:layout_toStartOf="@+id/textViewDelete"

android:padding="5dp"

android:text="Update"

android:textColor="#498C1A" />

<TextView

android:textStyle="bold"

android:id="@+id/textViewDelete"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignParentRight="true"

android:padding="5dp"

android:text="Delete"

android:textColor="#C20A10" />

</RelativeLayout>

Custom Adapter Class

Create one more inner class inside MainActivity class. We will name it HeroAdapter.

class HeroAdapter extends ArrayAdapter<Hero> {

//our hero list

List<Hero> heroList;

//constructor to get the list

public HeroAdapter(List<Hero> heroList) {

super(MainActivity.this, R.layout.layout_hero_list, heroList);

this.heroList = heroList;

}

//method returning list item

@Override

public View getView(int position, View convertView, ViewGroup parent) {

LayoutInflater inflater = getLayoutInflater();

View listViewItem = inflater.inflate(R.layout.layout_hero_list, null, true);

//getting the textview for displaying name

TextView textViewName = listViewItem.findViewById(R.id.textViewName);

//the update and delete textview

TextView textViewUpdate = listViewItem.findViewById(R.id.textViewUpdate);

TextView textViewDelete = listViewItem.findViewById(R.id.textViewDelete);

final Hero hero = heroList.get(position);

textViewName.setText(hero.getName());

//attaching click listener to update

textViewUpdate.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

//so when it is updating we will

//make the isUpdating as true

isUpdating = true;

//we will set the selected hero to the UI elements

editTextHeroId.setText(String.valueOf(hero.getId()));

editTextName.setText(hero.getName());

editTextRealname.setText(hero.getRealname());

ratingBar.setRating(hero.getRating());

spinnerTeam.setSelection(((ArrayAdapter<String>) spinnerTeam.getAdapter()).getPosition(hero.getTeamaffiliation()));

//we will also make the button text to Update

buttonAddUpdate.setText("Update");

}

});

//when the user selected delete

textViewDelete.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

// we will display a confirmation dialog before deleting

AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

builder.setTitle("Delete " + hero.getName())

.setMessage("Are you sure you want to delete it?")

.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {

//if the choice is yes we will delete the hero

//method is commented because it is not yet created

//deleteHero(hero.getId());

}

})

.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {

}

})

.setIcon(android.R.drawable.ic_dialog_alert)

.show();

}

});

return listViewItem;

}

Retrieving Heroes from the Database

Create a method named readHeroes().

private void readHeroes() {

PerformNetworkRequest request = new PerformNetworkRequest(Api.URL_READ_HEROES, null, CODE_GET_REQUEST);

request.execute();

}

Now one more method we need to refresh the Hero List. So create a method named refreshHeroList().

private void refreshHeroList(JSONArray heroes) throws JSONException {

//clearing previous heroes

heroList.clear();

//traversing through all the items in the json array

//the json we got from the response

for (int i = 0; i < heroes.length(); i++) {

//getting each hero object

JSONObject obj = heroes.getJSONObject(i);

//adding the hero to the list

heroList.add(new Hero(

obj.getInt("id"),

obj.getString("name"),

obj.getString("realname"),

obj.getInt("rating"),

obj.getString("teamaffiliation")

));

}

//creating the adapter and setting it to the listview

HeroAdapter adapter = new HeroAdapter(heroList);

listView.setAdapter(adapter);

}

Now also uncomment the commented method inside PeformNetworkRequest class and onCreate() method. You need to uncomment readHeroes() inside onCreate() and refreshHeroList() inside PerformNetworkRequest class.
Now you can try running the application.

android mysql tutorial - read operation — Android MySQL – Read Operation

You can see it is also working fine. Now lets do the UPDATE operation.

Update Operation

For updating we will create a new method named updateHero().

private void updateHero() {

String id = editTextHeroId.getText().toString();

String name = editTextName.getText().toString().trim();

String realname = editTextRealname.getText().toString().trim();

int rating = (int) ratingBar.getRating();

String team = spinnerTeam.getSelectedItem().toString();

if (TextUtils.isEmpty(name)) {

editTextName.setError("Please enter name");

editTextName.requestFocus();

return;

}

if (TextUtils.isEmpty(realname)) {

editTextRealname.setError("Please enter real name");

editTextRealname.requestFocus();

return;

}

HashMap<String, String> params = new HashMap<>();

params.put("id", id);

params.put("name", name);

params.put("realname", realname);

params.put("rating", String.valueOf(rating));

params.put("teamaffiliation", team);

PerformNetworkRequest request = new PerformNetworkRequest(Api.URL_UPDATE_HERO, params, CODE_POST_REQUEST);

request.execute();

buttonAddUpdate.setText("Add");

editTextName.setText("");

editTextRealname.setText("");

ratingBar.setRating(0);

spinnerTeam.setSelection(0);

isUpdating = false;

}

Now just uncomment the method updateHero() inside the click listener of buttonAddUpdate.
And now we can try updating a record.

android mysql tutorial - update operation — Android MySQL – Update Operation

So the update is also working absolutely fine. Now lets move to the last operation which is delete.

Delete Operation

For delete also we need a new method. So create a method named deleteHero().

private void deleteHero(int id) {

PerformNetworkRequest request = new PerformNetworkRequest(Api.URL_DELETE_HERO + id, null, CODE_GET_REQUEST);

request.execute();

}

Now uncomment the method deleteHero() inside the HeroAdapter class.
And lets test the delete operation as well.

android mysql tutorial - delete operation — Android MySQL – Delete Operation

So it is working fine as well. And we have done with all the basic CRUD operations.

The complete code for MainActivity

If you had some confusions following the above steps here is the complete code for MainActivity.java.

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package net.simplifiedlearning.myheroapp;

import android.content.DialogInterface;

import android.os.AsyncTask;

import android.os.Bundle;

import android.support.v7.app.AlertDialog;

import android.support.v7.app.AppCompatActivity;

import android.text.TextUtils;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.EditText;

import android.widget.ListView;

import android.widget.ProgressBar;

import android.widget.RatingBar;

import android.widget.Spinner;

import android.widget.TextView;

import android.widget.Toast;

import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;

import java.util.ArrayList;

import java.util.HashMap;

import java.util.List;

import static android.view.View.GONE;

public class MainActivity extends AppCompatActivity {

private static final int CODE_GET_REQUEST = 1024;

private static final int CODE_POST_REQUEST = 1025;

EditText editTextHeroId, editTextName, editTextRealname;

RatingBar ratingBar;

Spinner spinnerTeam;

ProgressBar progressBar;

ListView listView;

Button buttonAddUpdate;

List<Hero> heroList;

boolean isUpdating = false;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

editTextHeroId = (EditText) findViewById(R.id.editTextHeroId);

editTextName = (EditText) findViewById(R.id.editTextName);

editTextRealname = (EditText) findViewById(R.id.editTextRealname);

ratingBar = (RatingBar) findViewById(R.id.ratingBar);

spinnerTeam = (Spinner) findViewById(R.id.spinnerTeamAffiliation);

buttonAddUpdate = (Button) findViewById(R.id.buttonAddUpdate);

progressBar = (ProgressBar) findViewById(R.id.progressBar);

listView = (ListView) findViewById(R.id.listViewHeroes);

heroList = new ArrayList<>();

buttonAddUpdate.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

if (isUpdating) {

updateHero();

} else {

createHero();

}

});

readHeroes();

}

private void createHero() {

String name = editTextName.getText().toString().trim();

String realname = editTextRealname.getText().toString().trim();

int rating = (int) ratingBar.getRating();

String team = spinnerTeam.getSelectedItem().toString();

if (TextUtils.isEmpty(name)) {

editTextName.setError("Please enter name");

editTextName.requestFocus();

return;

}

if (TextUtils.isEmpty(realname)) {

editTextRealname.setError("Please enter real name");

editTextRealname.requestFocus();

return;

}

HashMap<String, String> params = new HashMap<>();

params.put("name", name);

params.put("realname", realname);

params.put("rating", String.valueOf(rating));

params.put("teamaffiliation", team);

PerformNetworkRequest request = new PerformNetworkRequest(Api.URL_CREATE_HERO, params, CODE_POST_REQUEST);

request.execute();

}

private void readHeroes() {

PerformNetworkRequest request = new PerformNetworkRequest(Api.URL_READ_HEROES, null, CODE_GET_REQUEST);

request.execute();

}

private void updateHero() {

String id = editTextHeroId.getText().toString();

String name = editTextName.getText().toString().trim();

String realname = editTextRealname.getText().toString().trim();

int rating = (int) ratingBar.getRating();

String team = spinnerTeam.getSelectedItem().toString();

if (TextUtils.isEmpty(name)) {

editTextName.setError("Please enter name");

editTextName.requestFocus();

return;

}

if (TextUtils.isEmpty(realname)) {

editTextRealname.setError("Please enter real name");

editTextRealname.requestFocus();

return;

}

HashMap<String, String> params = new HashMap<>();

params.put("id", id);

params.put("name", name);

params.put("realname", realname);

params.put("rating", String.valueOf(rating));

params.put("teamaffiliation", team);

PerformNetworkRequest request = new PerformNetworkRequest(Api.URL_UPDATE_HERO, params, CODE_POST_REQUEST);

request.execute();

buttonAddUpdate.setText("Add");

editTextName.setText("");

editTextRealname.setText("");

ratingBar.setRating(0);

spinnerTeam.setSelection(0);

isUpdating = false;

}

private void deleteHero(int id) {

PerformNetworkRequest request = new PerformNetworkRequest(Api.URL_DELETE_HERO + id, null, CODE_GET_REQUEST);

request.execute();

}

private void refreshHeroList(JSONArray heroes) throws JSONException {

heroList.clear();

for (int i = 0; i < heroes.length(); i++) {

JSONObject obj = heroes.getJSONObject(i);

heroList.add(new Hero(

obj.getInt("id"),

obj.getString("name"),

obj.getString("realname"),

obj.getInt("rating"),

obj.getString("teamaffiliation")

));

}

HeroAdapter adapter = new HeroAdapter(heroList);

listView.setAdapter(adapter);

}

private class PerformNetworkRequest extends AsyncTask<Void, Void, String> {

String url;

HashMap<String, String> params;

int requestCode;

PerformNetworkRequest(String url, HashMap<String, String> params, int requestCode) {

this.url = url;

this.params = params;

this.requestCode = requestCode;

}

@Override

protected void onPreExecute() {

super.onPreExecute();

progressBar.setVisibility(View.VISIBLE);

}

@Override

protected void onPostExecute(String s) {

super.onPostExecute(s);

progressBar.setVisibility(GONE);

try {

JSONObject object = new JSONObject(s);

if (!object.getBoolean("error")) {

Toast.makeText(getApplicationContext(), object.getString("message"), Toast.LENGTH_SHORT).show();

refreshHeroList(object.getJSONArray("heroes"));

}

} catch (JSONException e) {

e.printStackTrace();

}

@Override

protected String doInBackground(Void... voids) {

RequestHandler requestHandler = new RequestHandler();

if (requestCode == CODE_POST_REQUEST)

return requestHandler.sendPostRequest(url, params);

if (requestCode == CODE_GET_REQUEST)

return requestHandler.sendGetRequest(url);

return null;

}

class HeroAdapter extends ArrayAdapter<Hero> {

List<Hero> heroList;

public HeroAdapter(List<Hero> heroList) {

super(MainActivity.this, R.layout.layout_hero_list, heroList);

this.heroList = heroList;

}

@Override

public View getView(int position, View convertView, ViewGroup parent) {

LayoutInflater inflater = getLayoutInflater();

View listViewItem = inflater.inflate(R.layout.layout_hero_list, null, true);

TextView textViewName = listViewItem.findViewById(R.id.textViewName);

TextView textViewUpdate = listViewItem.findViewById(R.id.textViewUpdate);

TextView textViewDelete = listViewItem.findViewById(R.id.textViewDelete);

final Hero hero = heroList.get(position);

textViewName.setText(hero.getName());

textViewUpdate.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

isUpdating = true;

editTextHeroId.setText(String.valueOf(hero.getId()));

editTextName.setText(hero.getName());

editTextRealname.setText(hero.getRealname());

ratingBar.setRating(hero.getRating());

spinnerTeam.setSelection(((ArrayAdapter<String>) spinnerTeam.getAdapter()).getPosition(hero.getTeamaffiliation()));

buttonAddUpdate.setText("Update");

}

});

textViewDelete.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View view) {

AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

builder.setTitle("Delete " + hero.getName())

.setMessage("Are you sure you want to delete it?")

.setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {

deleteHero(hero.getId());

}

})

.setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {

public void onClick(DialogInterface dialog, int which) {

}

})

.setIcon(android.R.drawable.ic_dialog_alert)

.show();

}

});

return listViewItem;

}

So after following every step correctly your application will behave as shown below.

Android MySQL Tutorial – Source Code Download

If you are still facing troubles you can get my source code from below. It has everything, the server side scripts, database file and android project.

Android MySQL Tutorial Source Code

So thats all for this Android MySQL Tutorial friends. CRUD Operation is needed in almost every application so it is a very important thing. If you are having any confusions or queries regarding this Android MySQL tutorial don’t hesitate in asking on comments. And if you liked the post then PLEASE SHARE IT. Thank You 🙂

Android MySQL Tutorial to Perform Basic CRUD Operation

What is CRUD?

Why PHP and MySQL and Why Not SQLite?

Do we have only PHP and MySQL for this?

Building Web APIs

Creating Database

Creating PHP Project

Project Structure

Defining Constants

Connecting to Database

Performing Database Operations

Handling API Calls

Testing the API Calls

Create Operation

Read Operation

Update Operation

Delete Operation

Finalizing API Calls

Want to Explore Building RESTful APIs?

Android MySQL Tutorial

Creating a new Project

Creating Helper Classes

Class To Store API URLs

Hero Model Class

Request Handler

Defining Internet Permission in AndroidManifest

Designing User Interface

Class to Perform Network Request

Create Operation

Read Operation

List Layout

Custom Adapter Class

Retrieving Heroes from the Database

Update Operation

Delete Operation

The complete code for MainActivity

Android MySQL Tutorial – Source Code Download

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