如何使用JSON連接Android和PHP Mysql數據庫

轉自：http://blog.csdn.net/welovesunflower/article/details/7776438

我們先來看一個簡單的Android app例子（這裏是一個商品存貨清單項目），在Android程序中，我們可以訪問（call）PHP腳本來執行簡單的CRUD操作（創建，讀取，更新，刪除）。爲了使你對它的體系結構有一個大概的瞭解，這裏先說一下它是怎麼工作的。首先你的Android項目訪問（call）PHP腳本來執行一條數據操作，我們稱它爲“創建”。然後PHP腳本連接MySQL數據庫來執行這個操作。這樣，數據從Android程序流向PHP腳本，最終存儲在MySQL數據庫中。

好了，讓我們來深入的看一下。

請注意：這裏提供的代碼只是爲了使你能簡單的連接Android項目和PHP，MySQL。你不能把它作爲一個標準或者安全編程實踐。在生產環境中，理想情況下你需要避免使用任何可能造成潛在注入漏洞的代碼（比如MYSQL注入）。MYSQL注入是一個很大的話題，不可能用單獨的一篇文章來說清楚，並且它也不在本文討論的範圍內，所以本文不以討論。

1. 什麼是WAMP Server

WAMP是Windows,Apache,MySQL和PHP,Perl,Python的簡稱。WAMP是一個一鍵安裝的軟件，它爲開發PHP,MySQL Web應用程序提供一個環境。安裝這款軟件你相當於安裝了Apache,MySQL和PHP。或者，你也可以使用XAMP。

2. 安裝和使用WAMP Server

你可以從http://www.wampserver.com/en/下載WAMP，安裝完成之後，可以從開始->所有程序->WampServer->StartWampServer運行該程序。

在瀏覽器中輸入http://localhost/來測試你的服務器是否安裝成功。同樣的，也可以打開http://localhost/phpmyadmin來檢驗phpmyadmin是否安裝成功。

3. 創建和運行PHP項目

現在，你已經有一個能開發PHP和MYSQL項目的環境了。打開安裝WAMP Server的文件夾（在我的電腦中，是C:\wamp\），打開www文件夾，爲你的項目創建一個新的文件夾。你必須把項目中所有的文件放到這個文件夾中。

新建一個名爲android_connect的文件夾，並新建一個php文件，命名爲test.php，嘗試輸入一些簡單的php代碼（如下所示）。輸入下面的代碼後，打開http://localhost/android_connect/test.php，你會在瀏覽器中看到“Welcome,I am connecting Android to PHP,MySQL”（如果沒有正確輸入，請檢查WAMP配置是否正確）

test.php

<?php
echo"Welcome, I am connecting Android to PHP, MySQL";
?>

4. 創建MySQL數據庫和表

在本教程中，我創建了一個簡單的只有一張表的數據庫。我會用這個表來執行一些示例操作。現在，請在瀏覽器中輸入http://localhost/phpmyadmin/，並打開phpmyadmin。你可以用PhpMyAdmin工具創建數據庫和表。

創建數據庫和表：數據庫名：androidhive，表：product

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
);

5. 用PHP連接MySQL數據庫

現在，真正的服務器端編程開始了。新建一個PHP類來連接MYSQL數據庫。這個類的主要功能是打開數據庫連接和在不需要時關閉數據庫連接。

新建兩個文件db_config.php,db_connect.php

db_config.php--------存儲數據庫連接變量
db_connect.php-------連接數據庫的類文件

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
?>

這裏的DB_USER  DB_PASSWORD要換成自己數據庫對應的用戶名、密碼

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();
    }

}

?>

怎麼調用：當你想連接MySQl數據庫或者執行某些操作時，可以這樣使用db_connect.php

$db= new DB_CONNECT(); // creating class object(will open database connection)

6. 使用PHP執行基本CRUD操作

在這部分，我將講述使用PHP對MySQL數據庫執行基本CRUD（創建，讀取，更新，刪除）操作。

如果你是PHP和MySQL新手，我建議你可以先學習PHP和SQL基礎知識。

6. a)在MYSQL中新建一行（創建一行新的產品）

在你的PHP項目中新建一個php文件，命名爲create_product.php，並輸入以下代碼。該文件主要實現在products表中插入一個新的產品。

在下面的代碼我使用POST來讀取產品數據並把他們存儲在products表中。

最後我會輸出一些JSON返回值，以便返回給客戶端（Android項目）

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);
}
?>

對於上面的代碼，JSON的返回值會是：

當POST 參數丟失

{
"success": 0,
"message": "Required field(s) is missing"
}

當product成功創建

{
"success": 1,
"message": "Product successfully created."
}

當插入數據時出現錯誤

{
"success": 0,
"message": "Oops! An error occurred."
}

實際測試的時候，出現Required field(s) is missing php錯誤，我把$_POST換成$_GET就對了，對應的NewProductActivity也要換成GET方法

6. b)從MySQL中讀取一行信息（讀取產品詳細信息）

創建一個新的php文件，命名爲get_product_details.php，寫入以下代碼。

該文件通過傳遞產品id作爲POST參數獲得單個產品的詳細信息

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)從MySQL讀取所有行（讀取所有產品信息）

我們需要用json數據在Android設備上顯示所有的產品。

新建一個php文件，命名爲get_all_products.php，寫入以下代碼。

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)在MySQL中更新某一行（更新產品詳細信息）

新建一個php文件，命名爲update_product.php。每一個產品通過pid標識。

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)在MySQL中刪除某一行（刪除一個產品）

新建一個php文件，命名爲delete_product.php。該文件主要功能是從數據庫中刪除一個產品。

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"
}

到目前爲止，我們爲products表建立了一個簡單的接口。服務器端編程已經完成了，接下來讓我們開始真正的Android應用程序編程。

7. 新建一個Android應用程序

在Eclipse IDE中創建一個新項目，填寫所需的細節信息。

1. 新建項目，在菜單中選擇File->New->Android Project，把Activity類命名爲MainScreenActivity

2. 打開AndroidManifest.xml，添加以下代碼。我先在manifest文件中添加了所需的全部Activity類。同樣需要添加INTERNET連接權限（非常重要）
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. 在res->layout文件夾下新建一個xml文件，命名爲mian_screen.xml。這個layout文件包含兩個簡單的按鈕，通過這兩個按鈕可以查看所有產品和添加新產品。如下圖所示

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>

4. 打開MainScreenActivity.java爲main_screen.xml文件裏的兩個按鈕添加點擊事件

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);

            }
        });
    }
}

5. 在ListView中顯示所有產品（讀取）

現在我們需要一個Activity來以列表的形式顯示所有產品。如我們所知，使用ListView需要兩個xml文件，一個是列表佈局，另一個是單個的列表項佈局。在res->layout文件夾下新建兩個xml文件：all_product.xml和list_item.xml
all_product.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

<?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. 新建一個名爲AllProductActivity.java的類文件。

在下面的代碼中，

首先，在後臺AsyncTask線程中發送一個請求給get_all_products.php

然後，從get_all_products.php獲取JSON格式的數據，我爲json轉換了格式（parser），並使其顯示在ListView中。

如果沒有找到產品，會跳轉到AddNewProductActivity

AllProductActivity.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);
                }
            });

        }

    }
}

7. 添加一個新產品（寫入）

創建一個新的view和activity來向MySQL數據庫添加新產品。

新建一個簡單的表單，創建提供輸入產品名稱，價格和描述的EditText

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>

8. 新建一個Activity來處理向MySQL數據庫插入新產品。

新建名爲NewProductActivity.java的文件，輸入以下代碼。在下面的代碼中

首先，從EditText獲得用戶輸入的產品數據，格式化成基本參數格式

然後，向create_product.php發送請求，通過HTTP POST創建一個新的產品

最後，從create_product.php獲取json返回值，如果success值爲1，新得到的列表中就加入了新增的產品。

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();
        }

    }
}

9. 讀取，更新，刪除一項產品

你稍加註意就會發現，在AllProductsActivity.java中，選中列表的某一項，會進入EditProductActivity.java。

接下來新建一個名爲edit_product,xml的xml文件，創建類似create_product,xml的表單。

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. 對應edit_product.xml新建EditProductActivity.java，並輸入下列代碼。

在以下代碼中：

首先，從intent中讀取發送給ListView的產品id(pid)

然後，向get_product_details.php發送請求，獲得json格式的產品詳細信息，把它顯示在EditText中。

然後，當產品信息顯示在表單中後，如果用戶點擊保存按鈕，會向update_product.php發送另一個HTTP請求，更新數據庫中的產品信息

如果用戶點擊刪除按鈕，將會向delete_product.php發送請求，該產品慧聰MySQL數據庫中刪除，ListView刷新後顯示新的產品列表。

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();

        }

    }
}

11. JSONParser類

我用一個JSONParser類從URL獲得JSON格式的數據。這個類支持兩種http請求，GET和POST方法從URL獲取JSON數據

JSONParser.java

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;

    }
}

到這裏，本教程就結束了。

運行你的代碼，測試一下程序吧。你可能會遇到不少錯誤，經常使用LogCat來調試你的項目。

如果你不能解決那些錯誤，請在此留言。
原文鏈接：http://www.androidhive.info/2012/05/how-to-connect-android-with-php-mysql/

測試環境：WAMP: 2.4   Apache :2.4.4   PHP: 5.4.16

源碼下載地址： http://download.csdn.net/detail/welovesunflower/7383361