Project Guide from Lab2, Lab6 & Lab7

1. Create DB
2. DB_Connect.php
3. Set Permission
4. Set Volley
5. get_all_productsVolley.php and ListView
6. create_productVolley.php
7. get_product_detailsVolley.php
8. update_productVolley.php
9. delete_productVolley.php
10. How to install your mobile app on your phone?
11. How to change the icon for your mobile app?

Step 0:  Create Database and Tables (See Lab2)

Create mySQL database: EXAMPLE

 Get Familiarise with the use of phpMyAdmin

 Start XAMPP Control Panel and start the Apache and MySQL module

Then click on the Admin button of MySQL. 

Alternatively, you can open a web browser and type localhost/phpmyadmin

Click on the Database tab.  Then key in MyDatabase and click Create.

Create Table “products” in MyDatabase

  CREATE TABLE IF NOT EXISTS `products` (

  `pid` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(100) NOT NULL,
  `price` decimal(10,2) NOT NULL,
  `description` text,

  `qty`  int(10),

  `created_at` timestamp NULL DEFAULT CURRENT_TIMESTAMP,

   PRIMARY KEY (`pid`)
)

Press Ctrl+Enter to execute

the SQL query to create the table “products”

Insert values to the “products”
table
INSERT INTO products ( name, price, description) 
VALUES ( 'Long-grain rice, not parboiled, WKB', '3.00', '1000g');

Insert more values to the products table
INSERT INTO products (name, price, description) VALUES
('Long-grain rice, not parboiled, BL', '4.00', '1000g'),
('Long-grain rice, parboiled, in cooking bags, WKB', '5.00', '1000g');

Try other SQL statements like 
SELECT * FROM `products`

SELECT  `name`,`price` from products

SELECT DISTINCT `name` FROM products;
 
SELECT * FROM Products ORDER BY Price desc;
SELECT * FROM `products` WHERE pid ='1'

SELECT * FROM `products` WHERE name like '%not parboiled%'

DELETE FROM `products` WHERE pid ='2'

UPDATE `products` SET  `price`= '3.80' WHERE `pid` = '3'

SELECT AVG(Price) FROM Products;

SELECT COUNT(`pid`) FROM products;

SELECT * FROM products WHERE MONTH(`created_at`) = 7 AND YEAR(`created_at`) = 2024;

SELECT count(pid) FROM products WHERE YEAR(`created_at`) = 2024;


SELECT sum(price) FROM products WHERE name ="apple";

SELECT CURRENT_TIMESTAMP;

Reference on SQL Query:  https://www.w3schools.com/sql/sql_intro.asp
Let’s get started with creating a db_connect.php and
save it in C:\xampp\htdocs\products, using the Visual Studio Code.  
Type the following codes into db_connect.php.  It defines a class DB_CONNECT


db_connect.php
<?php
/**
* A class file to connect to database
*/
class DB_CONNECT { 
    
    var $myconn;
/* Function to connect with the database*/ 


function connect() {

define('DB_USER', "root"); // db user
define('DB_PASSWORD', ""); // db password (default is empty) 
define('DB_DATABASE', "mydatabase"); 
// database name 
define('DB_SERVER', "localhost"); 

// db server
// Connecting to mysql database
$con = mysqli_connect(DB_SERVER, DB_USER, DB_PASSWORD,DB_DATABASE) or die(mysqli_error($con));
$this->myconn = $con;
// returning connection cursor 

return  $this->myconn;



}
/* Function to close db connection */


function close($myconn) {
// closing db connection 
mysqli_close($myconn);


}
}
?>

Step 1:    Open the app's Module build.gradle file. Choose the correct build.gradle file as shown below:

dependencies {


    implementation 'com.android.volley:volley:1.2.1'
  
   ...........................
}

Step 2:  AndroidManifest.XML

 In the AndroidManifest file, set the Internet permission, by adding this line

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

 before the <application>   tag, which you did in the previous lab on Android Networking: Also, as the network data is sent in clear text via Volley library, add this line within tag 

android:usesCleartextTraffic="true

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <uses-feature
        android:name="android.hardware.camera"
        android:required="false" />

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

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.VolleySQLDatabase1"
        android:usesCleartextTraffic="true"
        tools:targetApi="31">
              
       <activity
            android:name=".EditProductActivity"
            android:exported="false" />
        <activity
            android:name=".NewProductActivity"
            android:exported="false" />
        <activity
            android:name=".AllProductsActivity"
            android:exported="false" />
        <activity
            android:name=".MainActivity"
            android:exported="false" />
 
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Click on the “Sync Now” icon on the top right hand corner, to download this Volley library into your Android Project.  

1.     copy the XML codes below and paste on the activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:gravity="center_horizontal">
    <!-- Sample Dashboard screen with Two buttons -->
    <!-- Button to view all products screen -->


    <Button android:id="@+id/btnViewProducts"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="View Products"
        android:layout_marginTop="25dip"/>


    <!-- Button to create a new product screen -->
    <Button android:id="@+id/btnCreateProduct"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Add New Products"
        android:layout_marginTop="25dip"/>




</LinearLayout>

1.     Modify MainActivity.java - Copy and paste the codes below. Note that the codes inside the onClick(View view) are commented out.

package mdad.localdata.volleysqldatabase1;

import android.content.Intent;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import androidx.activity.EdgeToEdge;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;



public class MainActivity extends AppCompatActivity {


    //public static String ipAddress = "http://192.168.10.114/";

    public static String ipAddress =   "http://mdad.atspace.cc/";


    public static String ipBaseAddress = ipAddress+"products";
    Button btnViewProducts;
    Button btnNewProduct;

    EditText etIpAddress;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // Buttons  binding XML to Java
       btnViewProducts =  findViewById(R.id.btnViewProducts);
       btnNewProduct =  findViewById(R.id.btnCreateProduct);
 

 

 



        btnViewProducts.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {


                Toast.makeText(getApplicationContext(),ipBaseAddress,Toast.LENGTH_LONG).show();


                // Launching All products Activity

             Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);

           startActivity(i);

            }
        });


        // view products click event
        btnNewProduct.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
            // Create New Product Activity
            Intent i = new Intent(getApplicationContext(), NewProductActivity.class);
                startActivity(i);
            }
        });

 



    }//onCreate



}

2. VIEW All products

PHP SERVER side

 http://172.30.103.225/products/get_all_productsVolley.php

get_all_productsVolley.php

<?php 

/** Following code will retrieve all the products */ 

// include db connect class 
require_once __DIR__ . '/db_connect.php'; 

// connecting to db 
$db= new DB_CONNECT(); 
$db->connect(); 

// get all products from products table 

$sqlCommand="SELECT * FROM products";


$result =mysqli_query($db->myconn, "$sqlCommand");

$productresult =""; 

// check for empty result 

if (mysqli_num_rows($result) > 0) 

{ // looping through all results 

    while ($row = mysqli_fetch_array($result)) 
    { 
        //each row of product is separated by ":" & each product information is separated by ";" 
        $productresult = $productresult.$row["pid"].";" .$row["name"].";".$row["price"].":"; 
    
    } 
        
        // return all products with separators to requesting client 
        //Android 
        echo ($productresult);   //echo to Android Client
        }else 
        
        { // no products found 
        
        echo("Error"); }    
        
        ?>

Android CLIENT  side 

 Proceed to add a new Empty Views Activity to the project app and name it “AllProductsActivity”.  We would like to display all the products retrieve from the database in a ListView in this activity

activity_all_products.XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">



    <!-- Main ListView Always give id value as list(@android:id/list) -->

    <ListView android:id="@+id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>



</LinearLayout>

AllProductsActivity.java

package mdad.localdata.volleysqldatabase1;

import android.os.Bundle;
import android.util.Log;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.Toast;

import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;


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.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

public class AllProductsActivity extends AppCompatActivity {

    //variable to store ListView
    ListView lv;
    //ArrayLisr to store product list from database
    ArrayList<HashMap<String, String>> productsList;

    // url to get all products list via the php file get_all_productsJson.php


    //http://172.30.103.225/products/get_all_productsVolley.php
    private static String url_all_products = MainActivity.ipBaseAddress+"/get_all_productsVolley.php";




    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_all_products);


         Log.i("URL",url_all_products );
        // get resource id of ListView
        lv = (ListView)findViewById(R.id.list);
        // ArrayList to store product info in Hashmap for ListView
        productsList = new ArrayList<HashMap<String, String>>();

        // re-usable method to use Volley to retrieve products from database
        postData(url_all_products, null );

        //http://172.30.103.225/products/get_all_productsVolley.php
        Log.i("URL",url_all_products);

 }  //onCreate
    public void postData(String url, Map params)
    {
        //create a RequestQueue for Volley
        RequestQueue queue = Volley.newRequestQueue(this);
        //create a StringRequest for Volley for HTTP Post
        StringRequest stringRequest = new StringRequest( Request.Method.POST, url,
                //response from server
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {


     //1;Long-grain rice, not parboiled, WKB;88.00:7;Pineapple King;19.00:11;Oat Bran;1.00:12;Apple;20.00:14;Soya Bean;2.00:


                        //check if error code received from server.
                        if (response.equals("Error"))
                        {
                            Toast.makeText(getApplicationContext(),"Error in retrieving database",Toast.LENGTH_LONG).show();
                            return;
                        }
                        //handle the response data received from server
                        //store each product from database records in String array
                        String[] products = response.split(":");
                        // for each product, retrieve the product details
                        for (int i = 0; i < products.length; i++) {
                            // Storing each product info in variable
                            String[] details = products[i].split(";");
                            String id = details[0];
                            String name = details[1];
                            String price = details[2];
                            // creating new HashMap
                            HashMap<String, String> map = new HashMap<String, String>();
                            // adding each product info to HashMap key-value pair
                            map.put("product_id", id);
                            map.put("product_name", name);
                            map.put("product_price", price);
                            // adding map HashList to ArrayList
                            productsList.add(map);
                        }
                        //populate the listview with product information from Hashmap
                        ListAdapter adapter = new SimpleAdapter(
                                AllProductsActivity.this, productsList,
                                R.layout.list_item, new String[]{"product_id",
                                "product_name","product_price"},
                                new int[]{R.id.pid, R.id.name,R.id.price});
                        // updating listview
                        lv.setAdapter(adapter);
                    }
                },
                //error in Volley
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        // handle error
                        Toast.makeText(getApplicationContext(),"Error in retrieving database",Toast.LENGTH_LONG).show();
                    }
                }
        );
        //add StringRequest to RequestQueue in Volley
        queue.add(stringRequest);
    }

}//end class

To Add New Product to Database

PHP SERVER side

  url_create_product  = "http://172.30.103.225/products/create_productVolley.php";

create_productVolley.php

<?php
if (isset($_POST['name']) && isset($_POST['price']) && isset($_POST['description']) )
{
//retrieve the values from html form
$name = $_POST['name'];
$price = $_POST['price'];
$descp = $_POST['description'];
// include db connect class
require_once __DIR__ . '/db_connect.php'; // include db connect class
// connecting to db
$db= new DB_CONNECT();
$db->connect();
    // get the search product from products table
//if update button is clicked in form submission
//$sqlCommand="INSERT INTO products (name,price,description) VALUES ('$name','$price','$description')";
$sqlCommand = "INSERT INTO products (name, price, description) VALUES ('$name', '$price', '$descp')";

//execute the sql command
$result = mysqli_query($db->myconn, "$sqlCommand");
if ($result)
{ //if result is successful
 echo ("Success");
}
else  
echo ("Error");
$db->close($db->myconn);
}
else  
{
echo ("Error");
}
?>

Android CLIENT  side 

activity_new_product.XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <!-- Name Label -->
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Product Name"
        android:paddingLeft="10dip"
        android:paddingRight="10dip"
        android:paddingTop="10dip"
        android:textSize="17dip"/>
    <!-- Input Name -->
    <EditText android:id="@+id/inputName"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dip"
        android:layout_marginBottom="15dip"
        android:singleLine="true"/>
    <!-- Price Label -->
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Price"
        android:paddingLeft="10dip"
        android:paddingRight="10dip"
        android:paddingTop="10dip"
        android:textSize="17dip"/>
    <!-- Input Price -->
    <EditText android:id="@+id/inputPrice"
        android:layout_width="fill_parent"

    android:layout_height="wrap_content"
    android:layout_margin="5dip"
    android:layout_marginBottom="15dip"
    android:singleLine="true"
    android:inputType="numberDecimal"/>
    <!-- Description Label -->
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Description"
        android:paddingLeft="10dip"
        android:paddingRight="10dip"
        android:paddingTop="10dip"
        android:textSize="17dip"/>
    <!-- Input description -->
    <EditText android:id="@+id/inputDesc"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dip"
        android:layout_marginBottom="15dip"
        android:lines="4"
        android:gravity="top"/>
    <!-- Button Create Product -->
    <Button android:id="@+id/btnCreateProduct"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Create Product"/>
</LinearLayout>

NewProductActivity.java

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" package mdad.localdata.volleysqldatabase1;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import androidx.activity.EdgeToEdge;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;

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.util.HashMap;
import java.util.Map;

public class NewProductActivity extends AppCompatActivity {


    EditText inputName;
    EditText inputPrice;
    EditText inputDesc;
    Button btnCreateProduct;
    String name ,price,description;


    //  url_create_product  = "http://172.30.103.225/products/create_productVolley.php";
    private static String url_create_product =MainActivity.ipBaseAddress+"/create_productVolley.php";




    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_new_product);


        // retrieve the resource id for EditText
        inputName = (EditText) findViewById(R.id.inputName);
        inputPrice = (EditText) findViewById(R.id.inputPrice);
        inputDesc = (EditText) findViewById(R.id.inputDesc);

        // retrieve the resource id for button
        btnCreateProduct = (Button) findViewById(R.id.btnCreateProduct);

        // button click event
        btnCreateProduct.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                //retrieve the values in EditText entered by user
                name = inputName.getText().toString();
                price = inputPrice.getText().toString();
                description = inputDesc.getText().toString();
                 //check for no empty values in EditText

                if (name.isEmpty() || price.isEmpty() || description.isEmpty())
                {
                    Toast.makeText(getApplicationContext(), "All fields must be filled",
                            Toast.LENGTH_LONG).show();
                    return;
                }

                //put the product info as key-values pair in HashMap
                Map<String,String> params_create = new HashMap<String,String>();
                params_create.put("name",name);
                params_create.put("price",price);
                params_create.put("description",description);
                //postData method to use Volley to update new product details in database
                postData(url_create_product,params_create);

            }
        });


    }//end of onCreate()


    public void postData(String url, Map params){
        //create a RequestQueue for Volley
        RequestQueue requestQueue = Volley.newRequestQueue(this);
        //create StringRequest for http post web request to send new product info to database
        StringRequest stringRequest = new StringRequest(Request.Method.POST, url,
                //response from server
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        if (response.equals("Error"))
                        {
                            Toast.makeText(getApplicationContext(),"Error in updating database",
                                    Toast.LENGTH_LONG).show();
                        }
                        if(response.equals("Success"))
                        {
                            Toast.makeText(getApplicationContext(),"Success in updating database",
                                    Toast.LENGTH_LONG).show();
                            finish();
                            //load the AllProductActivity with updated ListView
                            Intent i = new Intent (getApplicationContext(), AllProductsActivity.class);
                            startActivity(i);
                        }
                    }
                },
                //error in Volley
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        // handle error
                        Toast.makeText(getApplicationContext(),"Error in accessing database",Toast.LENGTH_LONG).show();
                    }
                }
        ) {
            @Nullable
            @Override
            // to send product info stored in HashMap params_create to server via HTTP Post
            protected Map<String, String> getParams() {
                return params;
            }
        };
        //add StringRequest to Volley Queue
        requestQueue.add(stringRequest);
    }




}// end of class>

Lab 7

Part 1: Get Selected Product Details

PHP SERVER side

private static final String url_product_details =
        MainActivity.ipBaseAddress+"/get_product_detailsVolley.php";

get_product_detailsVolley.php

<?php  
/*/*
 * Following code will get single product details from database
 * A product is identified by product id (pid)
 */
//check that pid is sent in HTTP Post
 if (isset($_POST["pid"])) {
  
    //get the pid from http post
     $pid = $_POST['pid'];
  
    // include db connect class
      require_once __DIR__ . '/db_connect.php';
    // connecting to db
      $db= new DB_CONNECT();
      $db->connect();
  
    // get the product from products table with given pid
      $sqlCommand="SELECT * FROM products WHERE pid = $pid";
      $result =mysqli_query($db->myconn, "$sqlCommand");

    $productresult ="";
    // check for empty result
    if (mysqli_num_rows($result) > 0) 
    {
        // looping through all results – in this case, only one product
        while ($row = mysqli_fetch_array($result)) {
          //product information is separated by ";"
            $productresult = $productresult.$row["pid"].";" .$row["name"].";".$row["price"].";".$row["description"].":";
        }
        //return product with separator to requesting client
        echo ($productresult);
    }
    else {
     // no products found
     echo("Error"); 
    }
} else echo("Error");
?>

update_productVolley.php

<?php
/*
 * Following code will update the selected product information
 * All product details are read from HTTP Post Request from Volley
 */
// check for required fields
if (isset($_POST['name']) && isset($_POST['price']) && isset($_POST['description']) && isset($_POST['pid']) ) {
 
    //retrieve the values for new product information
    $pid = $_POST['pid'];
    $name = $_POST['name'];
    $price = $_POST['price'];
    $description = $_POST['description'];
 
    // include db connect class
    require_once __DIR__ . '/db_connect.php';
    // connecting to db
    $myConnection= new DB_CONNECT();
    $myConnection->connect();
    
    //sql command to update the product in database
    $sqlCommand="UPDATE products SET name='$name', price='$price', description='$description' WHERE pid='$pid'";
    
    //execute the sql command
    $result =mysqli_query($myConnection->myconn, "$sqlCommand");

    // check the result
    if ($result) {
        echo("Success");

    } else {
        // failed to update
        echo("Error");
    }
    //close database connection
    $myConnection->close($myConnection->myconn);
   
} else {
    echo("Error");
}
?>

delete_productVolley.php

<?php
/*
 * Following code will update the selected product information
 * All product details are read from HTTP Post Request from Volley
 */
// check for required fields

//we only need the pid info so as to delete from the SQL table products
if ( isset($_POST['pid']) ) {
 
    //retrieve the values for new product information
    $pid = $_POST['pid'];
  
 
    // include db connect class
    require_once __DIR__ . '/db_connect.php';
    // connecting to db
    $myConnection= new DB_CONNECT();
    $myConnection->connect();
    
    //sql command to update the product in database
    $sqlCommand="delete from products WHERE pid='$pid'";
    
    //execute the sql command
    $result =mysqli_query($myConnection->myconn, "$sqlCommand");

    // check the result
    if ($result) {
        echo("Success");

    } else {
        // failed to update
        echo("Error");
    }
    //close database connection
    $myConnection->close($myConnection->myconn);
   
} else {
    echo("Error");
}

?>

Android CLIENT  side 

activity_edit_product.XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <!-- Name Label -->
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Product Name"
        android:paddingLeft="10dip"
        android:paddingRight="10dip"
        android:paddingTop="10dip"
        android:textSize="17dip"/>
    <!-- Input Name -->
    <EditText android:id="@+id/inputName"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dip"
        android:layout_marginBottom="15dip"
        android:singleLine="true"/>
    <!-- Price Label -->
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Price"
        android:paddingLeft="10dip"
        android:paddingRight="10dip"
        android:paddingTop="10dip"
        android:textSize="17dip"/>
    <!-- Input Price -->
    <EditText android:id="@+id/inputPrice"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dip"
        android:layout_marginBottom="15dip"
        android:singleLine="true"
        android:inputType="numberDecimal"/>
    <!-- Description Label -->
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Description"
        android:paddingLeft="10dip"
        android:paddingRight="10dip"
        android:paddingTop="10dip"
        android:textSize="17dip"/>
    <!-- Input description -->
    <EditText android:id="@+id/inputDesc"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_margin="5dip"
        android:layout_marginBottom="15dip"
        android:lines="4"
        android:gravity="top"/>

    <LinearLayout android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">
        <!-- Button Create Product -->
        <Button android:id="@+id/btnSave"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Save Changes"
            android:layout_weight="1"/>
        <!-- Button Create Product -->
        <Button android:id="@+id/btnDelete"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="Delete"
            android:layout_weight="1"/>
    </LinearLayout>
</LinearLayout>

EditProductActivity.java

package mdad.localdata.volleysqldatabase;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

import androidx.activity.EdgeToEdge;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;

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.util.HashMap;
import java.util.Map;

public class EditProductActivity extends AppCompatActivity {

    // url to get selected product details
    private static final String url_product_details =
            MainActivity.ipBaseAddress+"/get_product_detailsVolley.php";
    //To store the value of product id sent from AllProductActivity
    String pid;
    //define the type of volley request to be used to distinguish different volley response.
    private final int get_product_details = 1;
    private final int update_delete_product = 2;
    //variables to store resource ids of EditText & Buttons
    EditText txtName;
    EditText txtPrice;
    EditText txtDesc;
    Button btnSave;
    Button btnDelete;

    // url to update product
    private static final String url_update_product =
            MainActivity.ipBaseAddress+"/update_productVolley.php";
    // url to delete product
    private static final String url_delete_product =
            MainActivity.ipBaseAddress+"/delete_productVolley.php"


;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EdgeToEdge.enable(this);
        setContentView(R.layout.activity_edit_product);

        //get the resource ids
        txtName = (EditText) findViewById(R.id.inputName);
        txtPrice = (EditText) findViewById(R.id.inputPrice);
        txtDesc = (EditText) findViewById(R.id.inputDesc);
        btnSave = (Button) findViewById(R.id.btnSave);
        btnDelete = (Button) findViewById(R.id.btnDelete);
// create an Intent to receive pid sent from AllProductsActivity
        Intent i = getIntent();
// getting product id (pid) from intent
        pid = i.getStringExtra("product_id");
// use Hashmap to store product id in key-valye pair
        Map<String,String> params_pid = new HashMap<String,String>();
        params_pid.put("pid",pid);
//postData method to use Volley to retrieve selected product details from database
        postData(url_product_details, params_pid, get_product_details);


        //Save button click event
        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0){
                //retrieve new product info from EditText
                String name = txtName.getText().toString();
                String price = txtPrice.getText().toString();
                String description = txtDesc.getText().toString();
                //store the new product info in HashMap for sending to server
                Map<String,String> params_update = new HashMap<String,String>();
                params_update.put("pid",pid);
                params_update.put("name",name);
                params_update.put("price",price);
                params_update.put("description",description);
                //postData method to use Volley to update new product details in database
                postData(url_update_product,params_update,update_delete_product);
            }
        });


        //Save button click event
        btnDelete.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0){
                //retrieve new product info from EditText
                String name = txtName.getText().toString();
                String price = txtPrice.getText().toString();
                String description = txtDesc.getText().toString();
                //store the new product info in HashMap for sending to server
                Map<String,String> params_update = new HashMap<String,String>();
                params_update.put("pid",pid);
                //postData method to use Volley to update new product details in database
                postData(url_delete_product,params_update,update_delete_product);
            }
        });



    }

    public void postData(String url, Map params, final int requestType) {
        //create a RequestQueue for Volley
        RequestQueue requestQueue = Volley.newRequestQueue(this);
        //create a StringRequest for Volley for HTTP Post and send pid stored in params Map
        StringRequest stringRequest = new StringRequest(Request.Method.POST, url,
                //response from server
                new Response.Listener<String>() {
                    @Override
                    public void onResponse(String response) {
                        //if response from get product details request
                        if (requestType == get_product_details) {
                            //check if error code received from server.
                            if (response.equals("Error")) {
                                Toast.makeText(getApplicationContext(), "Error in accessing database",
                                        Toast.LENGTH_LONG).show();
                                return;
                            }
                            //handle the response data received from server
                            //store retrieved product from database in String array - only one product
                            String[] products = response.split(":");
                            //retrieve and store the product info in variable
                            String[] details = products[0].split(";");
                            String id = details[0];
                            String name = details[1];
                            String price = details[2];
                            String description = details[3];
                            //display product info in EditText
                            txtName.setText(name);
                            txtPrice.setText(price);
                            txtDesc.setText(description);
                        }
                        //if response from update delete request
                        if (requestType==update_delete_product) {
                            if (response.equals("Error"))
                            {
                                Toast.makeText(getApplicationContext(),"Error in updating database",
                                        Toast.LENGTH_LONG).show();
                            }
                            if(response.equals("Success"))
                            {
                                Toast.makeText(getApplicationContext(),"Success in updating database",
                                        Toast.LENGTH_LONG).show();
                                finish();
                                //load the AllProductActivity with updated ListView
                                Intent i = new Intent (getApplicationContext(), AllProductsActivity.class);
                                startActivity(i);
                            }
                        }





                    }
                },
                //Error in Volley
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        // handle Volley Error
                        Toast.makeText(getApplicationContext(), "Error in Volley ",
                                Toast.LENGTH_LONG).show();
                    }
                }
        ) {
            @Nullable
            @Override
            protected Map<String, String> getParams() {
                //send pid stored in HashMap using HTTP Post in Volley
                return params;
            }
        };
        //add StringRequest to Volley Queue
        requestQueue.add(stringRequest);
    }
}

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Create DB

DB_Connect

Set Permission

Volley

get_all_productsVolley.php

create_productVolley.php

get_product_detailsVolley.php

update_productVolley.php

delete_productVolley.php