Membuat project baru android menggunakan eclipse

Kali ini, kita akan membuat aplikasi Android client server PHP dan MySql Cara kerja aplikasi yang akan kita buat kali ini adalah aplikasi android memanggil script PHP untuk melakukan operasi data. Kemudian, script PHP menghubungkan ke database MySQL untuk melakukan operasi CRUD.
 
Langsung saja kita mulai, pada project kali ini, kita menggunakan wamp server sebaga server mysql nya. Bagi yang belum punya wamp server, silahkan download di & Install WAMP server dari situs resmi nya : www.wampserver.com/en/. Setelah Anda menginstal wamp server, jalankan program dari Start -> All Programs -> WampServer -> StartWampServer.


Inilah contoh source pada aplikasi yang kita akan buat kali ini :


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
);

Menghubungkan ke database MySql menggunakan PHP

Sekarang kita mulai koding di sisi server nya yaitu membuat file PHP untuk koneksi ke database MySQL. Tujuan utama dari file ini adalah untuk membuka koneksi ke database dan menutup koneksi sesuai request. Untuk itu, kita buat dua file yang disebut db_config.php dan db_connect.php

db_config.php - berfungsi sebagai variabel (konfigurasi) koneksi database
db_connect.php - file untuk koneksi ke database

Berikut ini adalah kode untuk dua file 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
<?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();
    }

}

?>

Membuat row di MySQL (Membuat row product baru)
Dalam project PHP, buat file PHP baru dengan nama create_product.php dan isikan kode berikut. File ini berfungsi untuk membuat produk baru di dalam tabel product.
Dalam kode berikut proses reading product data menggunakan POST dan menyimpannya dalam tabel product.
create_product.php

Membaca row data dari MySql (Membaca Detai Product)
Buat file php baru yang disebut get_product_details.php dan tuliskan kode berikut. File ini akan mendapatkan rincian satu produk dengan mengambil id produk (pid) sebagai parameter post.
get_product_details.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);
}
?>

Membaca Semua Row dari MySql (Membaca semua product)
Kita membutuhkan json untuk membuat daftar semua produk pada perangkat android. Untuk itu, buat file php baru dengan nama get_all_products.php dan ketik kode berikut.
get_all_products.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);
}
?>

Hasil JSON untuk kode di atas adalah seperti ini:
{
    "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
}

Update Row di MySql (Mengupdate product detail)
Buat file php bernama update_product.php untuk update informasi detail produk. Setiap produk diidentifikasi oleh pid. Ketikkan kode berikut :
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);
}
?>

Menghapus Row di MySql (Menghapus Product)
Operasi terakhir adalah penghapusan pada database. Buat file php baru kemudian beri nama dengan delete_product.php dan paste kode berikut. Fungsi utama dari file ini adalah untuk menghapus produk dari 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 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);
}
?>

Sampai saat ini, pengkodean di sisi server telah selesai, langkah selanjutnya adalah pembuatan aplikasi android nya.

 
Membuat Aplikas Android
Buat proyek baru di Eclipse IDE Anda dengan mengisi rincian yang dibutuhkan. 1 Buat proyek baru di Eclipse IDE dengan pergi ke File ⇒ New ⇒ Android Project kemudian beri nama kelas Activity nya sebagai MainScreenActivity. 2 Buka file AndroidManifest.xml dan tambahkan kode berikut. Pertama kita tambahkan semua kelas yang kita buat ke android manifest file. Dan juga tambahkan ijin INTERNET Connect agar proses client server bisa berjalan.
AndroidManifest.xml


Sekarang buat file xml baru di bres ⇒ layout folder kemudian beri nama dengan main_screen.xml. File layout ini berisi dua tombol sederhana untuk melihat semua produk dan menambahkan produk baru.
main_screen.xml


Buka class Activity utama dengan nama file MainScreenActivity.java kemudian tambahkan click listener untuk dua tombol yang telah dibuat di Layout main_screen.xml.
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);

            }
        });
    }
}

Menampilkan semua product kedalam ListView
Didalam Activity, kita menampilkan list semua produk kedalam ListView Format. Seperti kita ketahui, ListView layout membutuhkan dua file xml, satu untuk ListView nya dan lainnya adalah single list row. Buat dua file xml di res ⇒ Layout folder dan beri nama sebagai all_products.xml dan list_item.xml
all_products.xml

 
 


list_item.xml


 
 

 
 


Buat class file baru dan beri nama sebagai AllProductsActivity.java. Ketikkan kode berikut :
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);
                }
            });

        }

    }
}

Menambahkan Product Baru (Write)
Buat layout dan activity baru untuk menambahkan produk baru ke dalam database mysql. Buat bentuk sederhana yang berisi EditText untuk nama produk, harga dan deskripsi.
Buat file xml baru dan beri nama sebagai add_product.xml dan paste kode berikut untuk membuat form sederhana.
add_product.xml


 
 

 
 

 
 

 
 

 
 

 
 

 
 


Sekarang buat Activity baru untuk memasukkan produk baru ke dalam database mysql. Buat file class dan beri nama sebagai NewProductActivity.java dan ketik kode berikut.
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();
        }

    }
}

Membaca, Mengupdate dan Menghapus Single Product
Jika Anda memperhatikan code AllProductsActivity.java, Dalam ListView saya meluncurkan EditProductAcivity.java jika single list item dipilih. Untuk itu, buat file xml dengan nama edit_product.xml dan buat sama seperti create_product.xml.


 
 

 
 

 
 

 
 

 
 

 
 

 
     
 

 
 
 


Buat file class baru, berikan nama sebagai EditProductActivity.java, kemudian isikan kode berikut :
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<tring, 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();

        }

    }
}

JSON Parser Class
Saya menggunakan class JSON Parser untuk mendapatkan JSON dari URL. Kelas ini mendukung dua metode request http GET dan POST untuk mendapatkan json dari url.
package com.example.androidhive;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;

import android.util.Log;

public class JSONParser {

    static InputStream is = null;
    static JSONObject jObj = null;
    static String json = "";

    // constructor
    public JSONParser() {

    }

    // function get json from url
    // by making HTTP POST or GET mehtod
    public JSONObject makeHttpRequest(String url, String method,
            List<namevaluepair> params) {

        // Making HTTP request
        try {

            // check for request method
            if(method == "POST"){
                // request method is POST
                // defaultHttpClient
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpPost httpPost = new HttpPost(url);
                httpPost.setEntity(new UrlEncodedFormEntity(params));

                HttpResponse httpResponse = httpClient.execute(httpPost);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();

            }else if(method == "GET"){
                // request method is GET
                DefaultHttpClient httpClient = new DefaultHttpClient();
                String paramString = URLEncodedUtils.format(params, "utf-8");
                url += "?" + paramString;
                HttpGet httpGet = new HttpGet(url);

                HttpResponse httpResponse = httpClient.execute(httpGet);
                HttpEntity httpEntity = httpResponse.getEntity();
                is = httpEntity.getContent();
            }        

        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(
                    is, "iso-8859-1"), 8);
            StringBuilder sb = new StringBuilder();
            String line = null;
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
            is.close();
            json = sb.toString();
        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }

        // try parse the string to a JSON object
        try {
            jObj = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String
        return jObj;

    }
}

Jalankan proyek Anda kemudian uji aplikasi. Anda mungkin mendapatkan banyak kesalahan. Selalu gunakan Log Cat untuk debug aplikasi Anda, dan jika Anda tidak bisa memecahkan kesalahan Anda jangan lupa komentar di sini.