Friday, 7 November 2014

How to connect Android with PHP, MySQL

We are going see how to make a very simple Android app (in our case, a product inventory app) that will call a PHP script to perform basic CRUD(Create, Read, Update, Delete) operations. To brief you on the architecture, this is how it works. First your android app calls a PHP script in order to perform a data operation, lets say “create”. The PHP script then connects to your MySQL database to perform the operation.
So the data flows from your Android app to PHP script then finally is stored in your MySQL database. Allright, lets dig deeper.
 
Please note that the purpose of the code that I have provided here is to, ease you (beginner level) into connecting an Android app with PHP, MYSQL. You should not take this as a standard or secure coding practice. In production environment, you ideally need to avoid any code that will potentially inject vulnerabilities (like MYSQL Injection). MySQL injection itself is a huge topic and cannot be covered in this single post and that is not the agenda of this post either.

1. What is WAMP Server

WAMP is acronym for Windows, Apache, MySQL and PHP, Perl, Python. WAMP software is one click installer which creates an environment for developing PHP, MySQL web application. By installing this software you will be installing Apache, MySQL and PHP. Alternatively you can use XAMP Server also.
wamp server installation

2. Installing and Running WAMP Server

Download & Install WAMP server from www.wampserver.com/en/. Once you have installed wamp server, launch the program from Start -> All Programs -> WampServer -> StartWampServer.
You can test your server by opening the address http://localhost/ in your browser.
Also you can check phpmyadmin by opening http://localhost/phpmyadmin
Following is a screen cast of Downloading and Installing WAMP Server.

3. Creating and Running PHP Project

Now you have the environment ready to develop a PHP & MySQL project. Go to the location where you installed WAMP server (In my case i installed in C:\wamp\) and go to www folder and create a new folder for your project. You have to place all your project files inside this folder.
Create a folder called android_connect and create a new php file called test.php and try out simple php code. After placing following code try to open http://localhost/android_connect/test.php and you should see a message called “Welcome, I am connecting Android to PHP, MySQL“.
test.php
<?php
    echo "Welcome, I am connecting Android to PHP, MySQL";
?>
Following is a screen cast of Creating and Running a simple PHP project.

4. Creating MySQL Database and Tables

In this tutorial i am creating a simple database with one table. Through out this tutorial i am using same table to perform example operations. Now open phpmyadmin by opening the address http://localhost/phpmyadmin/ in your browser. You can use the PhpMyAdmin tool to create a database and a table.
I am creating a database named androidhive and a table called products.
CREATE DATABASE androidhive;
CREATE TABLE products(
pid int(11) primary key auto_increment,
name varchar(100) not null,
price decimal(10,2) not null,
description text,
created_at timestamp default now(),
updated_at timestamp
);
Following is a screen cast of Creating database and tables in phpmyadmin

5. Connecting to MySQL database using PHP

Now the actual server side coding starts. Create a PHP class to connect to MySQL database. The main purpose of this class is to open a connection to database and close the connection whenever its not needed. So create two files called db_config.php and db_connect.php
db_config.php – will have database connection variables
db_connect.php – a class file to connect to database
Following is code for two php files
db_config.php
db_config.php
<?php
 
/*
 * All database connection variables
 */
 
define('DB_USER', "root"); // db user
define('DB_PASSWORD', ""); // db password (mention your db password here)
define('DB_DATABASE', "androidhive"); // database name
define('DB_SERVER', "localhost"); // db server
?>
db_connect.php
db_connect.php
<?php
 
/**
 * A class file to connect to database
 */
class DB_CONNECT {
 
    // constructor
    function __construct() {
        // connecting to database
        $this->connect();
    }
 
    // destructor
    function __destruct() {
        // closing db connection
        $this->close();
    }
 
    /**
     * Function to connect with database
     */
    function connect() {
        // import database connection variables
        require_once __DIR__ . '/db_config.php';
 
        // Connecting to mysql database
        $con = mysql_connect(DB_SERVER, DB_USER, DB_PASSWORD) or die(mysql_error());
 
        // Selecing database
        $db = mysql_select_db(DB_DATABASE) or die(mysql_error()) or die(mysql_error());
 
        // returing connection cursor
        return $con;
    }
 
    /**
     * Function to close db connection
     */
    function close() {
        // closing db connection
        mysql_close();
    }
 
}
 
?>
Usage: When ever you want to connect to MySQL database and do some operations use the db_connect.php class like this
$db = new DB_CONNECT(); // creating class object(will open database connection)

6. Basic MySQL CRUD Operations using PHP

In this tutorial i am covering basic CRUD (Create, Read, Update, Delete) operations on MySQL database using PHP.
If you are a novice about PHP and MySQL i suggest, you to learn basic PHP and SQL here.

6.a) Creating a row in MySQL (Creating a new product row)

In your PHP project create a new php file called create_product.php and place the following code. This file is mainly for creating a new product in products table.
In the following code i am reading product data via POST and storing them in products table. At the end i am echoing appropriate JSON as response.
create_product.php
<?php
 
/*
 * Following code will create a new product row
 * All product details are read from HTTP Post Request
 */
 
// array for JSON response
$response = array();
 
// check for required fields
if (isset($_POST['name']) && isset($_POST['price']) && isset($_POST['description'])) {
 
    $name = $_POST['name'];
    $price = $_POST['price'];
    $description = $_POST['description'];
 
    // include db connect class
    require_once __DIR__ . '/db_connect.php';
 
    // connecting to db
    $db = new DB_CONNECT();
 
    // mysql inserting a new row
    $result = mysql_query("INSERT INTO products(name, price, description) VALUES('$name', '$price', '$description')");
 
    // check if row inserted or not
    if ($result) {
        // successfully inserted into database
        $response["success"] = 1;
        $response["message"] = "Product successfully created.";
 
        // echoing JSON response
        echo json_encode($response);
    } else {
        // failed to insert row
        $response["success"] = 0;
        $response["message"] = "Oops! An error occurred.";
 
        // echoing JSON response
        echo json_encode($response);
    }
} else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) is missing";
 
    // echoing JSON response
    echo json_encode($response);
}
?>
For the above code JSON response will be like
When POST param(s) is missing
{
    "success": 0,
    "message": "Required field(s) is missing"
}
When product is successfully created
{
    "success": 1,
    "message": "Product successfully created."
}
When error occurred while inserting data
{
    "success": 0,
    "message": "Oops! An error occurred."
}

6.b) Reading a Row from MySQL (Reading product details)

Create a new php file called get_product_details.php and write the following code. This file will get single product details by taking product id (pid) as post parameter.
get_product_details.php
<?php
 
/*
 * Following code will get single product details
 * A product is identified by product id (pid)
 */
 
// array for JSON response
$response = array();
 
// include db connect class
require_once __DIR__ . '/db_connect.php';
 
// connecting to db
$db = new DB_CONNECT();
 
// check for post data
if (isset($_GET["pid"])) {
    $pid = $_GET['pid'];
 
    // get a product from products table
    $result = mysql_query("SELECT *FROM products WHERE pid = $pid");
 
    if (!empty($result)) {
        // check for empty result
        if (mysql_num_rows($result) > 0) {
 
            $result = mysql_fetch_array($result);
 
            $product = array();
            $product["pid"] = $result["pid"];
            $product["name"] = $result["name"];
            $product["price"] = $result["price"];
            $product["description"] = $result["description"];
            $product["created_at"] = $result["created_at"];
            $product["updated_at"] = $result["updated_at"];
            // success
            $response["success"] = 1;
 
            // user node
            $response["product"] = array();
 
            array_push($response["product"], $product);
 
            // echoing JSON response
            echo json_encode($response);
        } else {
            // no product found
            $response["success"] = 0;
            $response["message"] = "No product found";
 
            // echo no users JSON
            echo json_encode($response);
        }
    } else {
        // no product found
        $response["success"] = 0;
        $response["message"] = "No product found";
 
        // echo no users JSON
        echo json_encode($response);
    }
} else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) is missing";
 
    // echoing JSON response
    echo json_encode($response);
}
?>
The json response for the above file will be
When successfully getting product details
{
    "success": 1,
    "product": [
        {
            "pid": "1",
            "name": "iPHone 4S",
            "price": "300.00",
            "description": "iPhone 4S white",
            "created_at": "2012-04-29 01:41:42",
            "updated_at": "0000-00-00 00:00:00"
        }
    ]
}
When no product found with matched pid
{
    "success": 0,
    "message": "No product found"
}

6.c) Reading All Rows from MySQL (Reading all products)

We need a json to list all the products on android device. So create a new php file named get_all_products.php and write following code.
get_all_products.php
<?php
 
/*
 * Following code will list all the products
 */
 
// array for JSON response
$response = array();
 
// include db connect class
require_once __DIR__ . '/db_connect.php';
 
// connecting to db
$db = new DB_CONNECT();
 
// get all products from products table
$result = mysql_query("SELECT *FROM products") or die(mysql_error());
 
// check for empty result
if (mysql_num_rows($result) > 0) {
    // looping through all results
    // products node
    $response["products"] = array();
 
    while ($row = mysql_fetch_array($result)) {
        // temp user array
        $product = array();
        $product["pid"] = $row["pid"];
        $product["name"] = $row["name"];
        $product["price"] = $row["price"];
        $product["created_at"] = $row["created_at"];
        $product["updated_at"] = $row["updated_at"];
 
        // push single product into final response array
        array_push($response["products"], $product);
    }
    // success
    $response["success"] = 1;
 
    // echoing JSON response
    echo json_encode($response);
} else {
    // no products found
    $response["success"] = 0;
    $response["message"] = "No products found";
 
    // echo no users JSON
    echo json_encode($response);
}
?>
And the JSON response for above code
Listing all Products
{
    "products": [
        {
            "pid": "1",
            "name": "iPhone 4S",
            "price": "300.00",
            "created_at": "2012-04-29 02:04:02",
            "updated_at": "0000-00-00 00:00:00"
        },
        {
            "pid": "2",
            "name": "Macbook Pro",
            "price": "600.00",
            "created_at": "2012-04-29 02:04:51",
            "updated_at": "0000-00-00 00:00:00"
        },
        {
            "pid": "3",
            "name": "Macbook Air",
            "price": "800.00",
            "created_at": "2012-04-29 02:05:57",
            "updated_at": "0000-00-00 00:00:00"
        },
        {
            "pid": "4",
            "name": "OS X Lion",
            "price": "100.00",
            "created_at": "2012-04-29 02:07:14",
            "updated_at": "0000-00-00 00:00:00"
        }
    ],
    "success": 1
}
When products not found
{
    "success": 0,
    "message": "No products found"
}

6.d) Updating a Row in MySQL (Updating product details)

Create a php file named update_product.php to update product details. Each product is identified by pid.
update_product.php
<?php
 
/*
 * Following code will update a product information
 * A product is identified by product id (pid)
 */
 
// array for JSON response
$response = array();
 
// check for required fields
if (isset($_POST['pid']) && isset($_POST['name']) && isset($_POST['price']) && isset($_POST['description'])) {
 
    $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
    $db = new DB_CONNECT();
 
    // mysql update row with matched pid
    $result = mysql_query("UPDATE products SET name = '$name', price = '$price', description = '$description' WHERE pid = $pid");
 
    // check if row inserted or not
    if ($result) {
        // successfully updated
        $response["success"] = 1;
        $response["message"] = "Product successfully updated.";
 
        // echoing JSON response
        echo json_encode($response);
    } else {
 
    }
} else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) is missing";
 
    // echoing JSON response
    echo json_encode($response);
}
?>
The json reponse of above code, when product is updated successfully
{
    "success": 1,
    "message": "Product successfully updated."
}

6.e) Deleting a Row in MySQL (Deleting a product)

The last operation is deletion on database. Create a new php file called delete_product.php and paste the following code. The main functionality of this file is to delete a product from database.
delete_product.php
<?php
 
/*
 * Following code will delete a product from table
 * A product is identified by product id (pid)
 */
 
// array for JSON response
$response = array();
 
// check for required fields
if (isset($_POST['pid'])) {
    $pid = $_POST['pid'];
 
    // include db connect class
    require_once __DIR__ . '/db_connect.php';
 
    // connecting to db
    $db = new DB_CONNECT();
 
    // mysql update row with matched pid
    $result = mysql_query("DELETE FROM products WHERE pid = $pid");
 
    // check if row deleted or not
    if (mysql_affected_rows() > 0) {
        // successfully updated
        $response["success"] = 1;
        $response["message"] = "Product successfully deleted";
 
        // echoing JSON response
        echo json_encode($response);
    } else {
        // no product found
        $response["success"] = 0;
        $response["message"] = "No product found";
 
        // echo no users JSON
        echo json_encode($response);
    }
} else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) is missing";
 
    // echoing JSON response
    echo json_encode($response);
}
?>
When product successfully deleted
{
    "success": 1,
    "message": "Product successfully deleted"
}
When product not found
{
    "success": 0,
    "message": "No product found"
}
Until now, we built a simple api for our products table. We are now done with the server side coding (PHP) and its time to take a break and start our actual android application coding.

7. Creating Android Application

Create a new project in your Eclipse IDE by filling the required details.
1. Create new project in Eclipse IDE by going to File ⇒ New ⇒ Android Project and name the Activity class name as MainScreenActivity.
2. Open your AndroidManifest.xml file and add following code. First i am adding all the classes i am creating to manifest file. Also i am adding INTERNET Connect permission.
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.androidhive"
    android:versionCode="1"
    android:versionName="1.0" >
 
    <uses-sdk android:minSdkVersion="8" />
 
    <application
        android:configChanges="keyboardHidden|orientation"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
 
        <activity
            android:name=".MainScreenActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
 
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
 
        <!-- All Product Activity -->
        <activity
            android:name=".AllProductsActivity"
            android:label="All Products" >
        </activity>
 
        <!-- Add Product Activity -->
        <activity
            android:name=".NewProductActivity"
            android:label="Add New Product" >
        </activity>
 
        <!-- Edit Product Activity -->
        <activity
            android:name=".EditProductActivity"
            android:label="Edit Product" >
        </activity>
    </application>
 
    <!--  Internet Permissions -->
    <uses-permission android:name="android.permission.INTERNET" />
 
</manifest>
3. Now create a new xml file under res ⇒ layout folder and name it as main_screen.xml This layout file contains two simple buttons to view all products and add a new product.
main_screen.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>
main screen
4. Open you main activity class which is MainScreenActivity.java and write click events for two button which are mentioned in main_screen.xml layout.
MainScreenActivity.java
package com.example.androidhive;
 
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
 
public class MainScreenActivity extends Activity{
 
    Button btnViewProducts;
    Button btnNewProduct;
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main_screen);
 
        // Buttons
        btnViewProducts = (Button) findViewById(R.id.btnViewProducts);
        btnNewProduct = (Button) findViewById(R.id.btnCreateProduct);
 
        // view products click event
        btnViewProducts.setOnClickListener(new View.OnClickListener() {
 
            @Override
            public void onClick(View view) {
                // 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) {
                // Launching create new product activity
                Intent i = new Intent(getApplicationContext(), NewProductActivity.class);
                startActivity(i);
 
            }
        });
    }
}

Displaying All Products in ListView (Read)

5. Now we need an Activity display all the products in list view format. As we know list view needs two xml files, one for listview and other is for single list row. Create two xml files under res ⇒ layout folder and name it as all_products.xml and list_item.xml
all_products.xml
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="@android:id/list"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"/>
 
</LinearLayout>
list_item.xml
list_item.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="wrap_content"
    android:orientation="vertical" >
 
    <!-- Product id (pid) - will be HIDDEN - used to pass to other activity -->
    <TextView
        android:id="@+id/pid"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:visibility="gone" />
 
    <!-- Name Label -->
    <TextView
        android:id="@+id/name"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:paddingTop="6dip"
        android:paddingLeft="6dip"
        android:textSize="17dip"
        android:textStyle="bold" />
 
</LinearLayout>
6. Create a new class file and name it as AllProductsActivity.java. In the following code
-> First a request is send to get_all_products.php file using a Background Async task thread.
-> After getting JSON from get_all_products.php, i parsed it and displayed in a listview.
-> If there are no products found AddNewProductAcivity is launched.
AllProductsActivity.java
package com.example.androidhive;
 
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
 
import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
 
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
 
public class AllProductsActivity extends ListActivity {
 
    // Progress Dialog
    private ProgressDialog pDialog;
 
    // Creating JSON Parser object
    JSONParser jParser = new JSONParser();
 
    ArrayList<HashMap<String, String>> productsList;
 
    // url to get all products list
    private static String url_all_products = "http://api.androidhive.info/android_connect/get_all_products.php";
 
    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCTS = "products";
    private static final String TAG_PID = "pid";
    private static final String TAG_NAME = "name";
 
    // products JSONArray
    JSONArray products = null;
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.all_products);
 
        // Hashmap for ListView
        productsList = new ArrayList<HashMap<String, String>>();
 
        // Loading products in Background Thread
        new LoadAllProducts().execute();
 
        // Get listview
        ListView lv = getListView();
 
        // on seleting single product
        // launching Edit Product Screen
        lv.setOnItemClickListener(new OnItemClickListener() {
 
            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // getting values from selected ListItem
                String pid = ((TextView) view.findViewById(R.id.pid)).getText()
                        .toString();
 
                // Starting new intent
                Intent in = new Intent(getApplicationContext(),
                        EditProductActivity.class);
                // sending pid to next activity
                in.putExtra(TAG_PID, pid);
 
                // starting new activity and expecting some response back
                startActivityForResult(in, 100);
            }
        });
 
    }
 
    // Response from Edit Product Activity
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        // if result code 100
        if (resultCode == 100) {
            // if result code 100 is received
            // means user edited/deleted product
            // reload this screen again
            Intent intent = getIntent();
            finish();
            startActivity(intent);
        }
 
    }
 
    /**
     * Background Async Task to Load all product by making HTTP Request
     * */
    class LoadAllProducts extends AsyncTask<String, String, String> {
 
        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(AllProductsActivity.this);
            pDialog.setMessage("Loading products. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }
 
        /**
         * getting All products from url
         * */
        protected String doInBackground(String... args) {
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            // getting JSON string from URL
            JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
 
            // Check your log cat for JSON reponse
            Log.d("All Products: ", json.toString());
 
            try {
                // Checking for SUCCESS TAG
                int success = json.getInt(TAG_SUCCESS);
 
                if (success == 1) {
                    // products found
                    // Getting Array of Products
                    products = json.getJSONArray(TAG_PRODUCTS);
 
                    // looping through All Products
                    for (int i = 0; i < products.length(); i++) {
                        JSONObject c = products.getJSONObject(i);
 
                        // Storing each json item in variable
                        String id = c.getString(TAG_PID);
                        String name = c.getString(TAG_NAME);
 
                        // creating new HashMap
                        HashMap<String, String> map = new HashMap<String, String>();
 
                        // adding each child node to HashMap key => value
                        map.put(TAG_PID, id);
                        map.put(TAG_NAME, name);
 
                        // adding HashList to ArrayList
                        productsList.add(map);
                    }
                } else {
                    // no products found
                    // Launch Add New product Activity
                    Intent i = new Intent(getApplicationContext(),
                            NewProductActivity.class);
                    // Closing all previous activities
                    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(i);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
 
            return null;
        }
 
        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after getting all products
            pDialog.dismiss();
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */
                    ListAdapter adapter = new SimpleAdapter(
                            AllProductsActivity.this, productsList,
                            R.layout.list_item, new String[] { TAG_PID,
                                    TAG_NAME},
                            new int[] { R.id.pid, R.id.name });
                    // updating listview
                    setListAdapter(adapter);
                }
            });
 
        }
 
    }
}
android list products

Adding a New Product (Write)

7. Create a new view and acivity to add a new product into mysql database. Create a simple form which contains EditText for product name, price and description.
Create a new xml file and name it as add_product.xml and paste the following code to create a simple form.
add_product.xml
add_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>
android adding new product
8. Now create new Activity to insert a new product into mysql database. Create a class file and name it as NewProductActivity.java and type the following code. In the following code
-> First new product data is read from the EditText form and formatted into a basic params.
-> A request is made to create_product.php to create a new product through HTTP post.
-> After getting json response from create_product.php, If success bit is 1 then list view is refreshed with newly added product.
NewProductActivity.java
package com.example.androidhive;
 
import java.util.ArrayList;
import java.util.List;
 
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;
 
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
 
public class NewProductActivity extends Activity {
 
    // Progress Dialog
    private ProgressDialog pDialog;
 
    JSONParser jsonParser = new JSONParser();
    EditText inputName;
    EditText inputPrice;
    EditText inputDesc;
 
    // url to create new product
    private static String url_create_product = "http://api.androidhive.info/android_connect/create_product.php";
 
    // JSON Node names
    private static final String TAG_SUCCESS = "success";
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_product);
 
        // Edit Text
        inputName = (EditText) findViewById(R.id.inputName);
        inputPrice = (EditText) findViewById(R.id.inputPrice);
        inputDesc = (EditText) findViewById(R.id.inputDesc);
 
        // Create button
        Button btnCreateProduct = (Button) findViewById(R.id.btnCreateProduct);
 
        // button click event
        btnCreateProduct.setOnClickListener(new View.OnClickListener() {
 
            @Override
            public void onClick(View view) {
                // creating new product in background thread
                new CreateNewProduct().execute();
            }
        });
    }
 
    /**
     * Background Async Task to Create new product
     * */
    class CreateNewProduct extends AsyncTask<String, String, String> {
 
        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(NewProductActivity.this);
            pDialog.setMessage("Creating Product..");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }
 
        /**
         * Creating product
         * */
        protected String doInBackground(String... args) {
            String name = inputName.getText().toString();
            String price = inputPrice.getText().toString();
            String description = inputDesc.getText().toString();
 
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("name", name));
            params.add(new BasicNameValuePair("price", price));
            params.add(new BasicNameValuePair("description", description));
 
            // getting JSON Object
            // Note that create product url accepts POST method
            JSONObject json = jsonParser.makeHttpRequest(url_create_product,
                    "POST", params);
 
            // check log cat fro response
            Log.d("Create Response", json.toString());
 
            // check for success tag
            try {
                int success = json.getInt(TAG_SUCCESS);
 
                if (success == 1) {
                    // successfully created product
                    Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);
                    startActivity(i);
 
                    // closing this screen
                    finish();
                } else {
                    // failed to create product
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
 
            return null;
        }
 
        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog once done
            pDialog.dismiss();
        }
 
    }
}

Reading, Updating and Deleting a Single Product

9. If you notice the AllProductsActivity.java, In listview i am launching EditProductAcivity.java once a single list item is selected. So create xml file called edit_product.xml and create a form which is same as create_product.xml.
edit_product.xml
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>
10. Create a class file for edit_product.xml and name it as EditProductActivity.java and fill it with following code. In the following code
-> First product id (pid) is read from the intent which is sent from listview.
-> A request is made to get_product_details.php and after getting product details in json format, I parsed the json and displayed in EditText.
-> After displaying product data in the form if user clicks on Save Changes Button, another HTTP request is made to update_product.php to store updated product data.
-> If the user selected Delete Product Button, HTTP request is made to delete_product.php and product is deleted from mysql database, and listview is refreshed with new product list.
EditProductActivity.java
package com.example.androidhive;
 
import java.util.ArrayList;
import java.util.List;
 
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
 
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
 
public class EditProductActivity extends Activity {
 
    EditText txtName;
    EditText txtPrice;
    EditText txtDesc;
    EditText txtCreatedAt;
    Button btnSave;
    Button btnDelete;
 
    String pid;
 
    // Progress Dialog
    private ProgressDialog pDialog;
 
    // JSON parser class
    JSONParser jsonParser = new JSONParser();
 
    // single product url
    private static final String url_product_detials = "http://api.androidhive.info/android_connect/get_product_details.php";
 
    // url to update product
    private static final String url_update_product = "http://api.androidhive.info/android_connect/update_product.php";
 
    // url to delete product
    private static final String url_delete_product = "http://api.androidhive.info/android_connect/delete_product.php";
 
    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCT = "product";
    private static final String TAG_PID = "pid";
    private static final String TAG_NAME = "name";
    private static final String TAG_PRICE = "price";
    private static final String TAG_DESCRIPTION = "description";
 
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.edit_product);
 
        // save button
        btnSave = (Button) findViewById(R.id.btnSave);
        btnDelete = (Button) findViewById(R.id.btnDelete);
 
        // getting product details from intent
        Intent i = getIntent();
 
        // getting product id (pid) from intent
        pid = i.getStringExtra(TAG_PID);
 
        // Getting complete product details in background thread
        new GetProductDetails().execute();
 
        // save button click event
        btnSave.setOnClickListener(new View.OnClickListener() {
 
            @Override
            public void onClick(View arg0) {
                // starting background task to update product
                new SaveProductDetails().execute();
            }
        });
 
        // Delete button click event
        btnDelete.setOnClickListener(new View.OnClickListener() {
 
            @Override
            public void onClick(View arg0) {
                // deleting product in background thread
                new DeleteProduct().execute();
            }
        });
 
    }
 
    /**
     * Background Async Task to Get complete product details
     * */
    class GetProductDetails extends AsyncTask<String, String, String> {
 
        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(EditProductActivity.this);
            pDialog.setMessage("Loading product details. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }
 
        /**
         * Getting product details in background thread
         * */
        protected String doInBackground(String... params) {
 
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    // Check for success tag
                    int success;
                    try {
                        // Building Parameters
                        List<NameValuePair> params = new ArrayList<NameValuePair>();
                        params.add(new BasicNameValuePair("pid", pid));
 
                        // getting product details by making HTTP request
                        // Note that product details url will use GET request
                        JSONObject json = jsonParser.makeHttpRequest(
                                url_product_detials, "GET", params);
 
                        // check your log for json response
                        Log.d("Single Product Details", json.toString());
 
                        // json success tag
                        success = json.getInt(TAG_SUCCESS);
                        if (success == 1) {
                            // successfully received product details
                            JSONArray productObj = json
                                    .getJSONArray(TAG_PRODUCT); // JSON Array
 
                            // get first product object from JSON Array
                            JSONObject product = productObj.getJSONObject(0);
 
                            // product with this pid found
                            // Edit Text
                            txtName = (EditText) findViewById(R.id.inputName);
                            txtPrice = (EditText) findViewById(R.id.inputPrice);
                            txtDesc = (EditText) findViewById(R.id.inputDesc);
 
                            // display product data in EditText
                            txtName.setText(product.getString(TAG_NAME));
                            txtPrice.setText(product.getString(TAG_PRICE));
                            txtDesc.setText(product.getString(TAG_DESCRIPTION));
 
                        }else{
                            // product with pid not found
                        }
                    } catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            });
 
            return null;
        }
 
        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog once got all details
            pDialog.dismiss();
        }
    }
 
    /**
     * Background Async Task to  Save product Details
     * */
    class SaveProductDetails extends AsyncTask<String, String, String> {
 
        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(EditProductActivity.this);
            pDialog.setMessage("Saving product ...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }
 
        /**
         * Saving product
         * */
        protected String doInBackground(String... args) {
 
            // getting updated data from EditTexts
            String name = txtName.getText().toString();
            String price = txtPrice.getText().toString();
            String description = txtDesc.getText().toString();
 
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair(TAG_PID, pid));
            params.add(new BasicNameValuePair(TAG_NAME, name));
            params.add(new BasicNameValuePair(TAG_PRICE, price));
            params.add(new BasicNameValuePair(TAG_DESCRIPTION, description));
 
            // sending modified data through http request
            // Notice that update product url accepts POST method
            JSONObject json = jsonParser.makeHttpRequest(url_update_product,
                    "POST", params);
 
            // check json success tag
            try {
                int success = json.getInt(TAG_SUCCESS);
 
                if (success == 1) {
                    // successfully updated
                    Intent i = getIntent();
                    // send result code 100 to notify about product update
                    setResult(100, i);
                    finish();
                } else {
                    // failed to update product
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
 
            return null;
        }
 
        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog once product uupdated
            pDialog.dismiss();
        }
    }
 
    /*****************************************************************
     * Background Async Task to Delete Product
     * */
    class DeleteProduct extends AsyncTask<String, String, String> {
 
        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(EditProductActivity.this);
            pDialog.setMessage("Deleting Product...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }
 
        /**
         * Deleting product
         * */
        protected String doInBackground(String... args) {
 
            // Check for success tag
            int success;
            try {
                // Building Parameters
                List<NameValuePair> params = new ArrayList<NameValuePair>();
                params.add(new BasicNameValuePair("pid", pid));
 
                // getting product details by making HTTP request
                JSONObject json = jsonParser.makeHttpRequest(
                        url_delete_product, "POST", params);
 
                // check your log for json response
                Log.d("Delete Product", json.toString());
 
                // json success tag
                success = json.getInt(TAG_SUCCESS);
                if (success == 1) {
                    // product successfully deleted
                    // notify previous activity by sending code 100
                    Intent i = getIntent();
                    // send result code 100 to notify about product deletion
                    setResult(100, i);
                    finish();
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }
 
            return null;
        }
 
        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog once product deleted
            pDialog.dismiss();
 
        }
 
    }
}
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