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.
<?php/* * Following code will update a product information * A product is identified by product id (pid) */// array for JSON response$response = array();// check for required fieldsif (isset($_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.
<?php/* * Following code will delete a product from table * A product is identified by product id (pid) */// array for JSON response$response = array();// check for required fieldsif (isset($_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.
<?xml version="1.0" encoding="utf-8"?> 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.
<?xml version="1.0" encoding="utf-8"?> 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> |
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.
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); } }); }} |