如何使用JSON连接Android和PHP Mysql数据库

我们先来看一个简单的Android app例子（这里是一个商品存货清单项目），在Android程序中，我们可以访问（call）PHP脚本来执行简单的CRUD操作（创建，读取，更新，删除）。为了使你对它的体系结构有一个大概的了解，这里先说一下它是怎么工作的。首先你的Android项目访问（call）PHP脚本来执行一条数据操作，我们称它为“创建”。然后PHP脚本连接MySQL数据库来执行这个操作。这样，数据从Android程序流向PHP脚本，最终存储在MySQL数据库中。

好了，让我们来深入的看一下。

请注意：这里提供的代码只是为了使你能简单的连接Android项目和PHP，MySQL。你不能把它作为一个标准或者安全编程实践。在生产环境中，理想情况下你需要避免使用任何可能造成潜在注入漏洞的代码（比如MYSQL注入）。MYSQL注入是一个很大的话题，不可能用单独的一篇文章来说清楚，并且它也不在本文讨论的范围内，所以本文不以讨论。

1. 什么是WAMP Server

WAMP是Windows,Apache,MySQL和PHP,Perl,Python的简称。WAMP是一个一键安装的软件，它为开发PHP,MySQL Web应用程序提供一个环境。安装这款软件你相当于安装了Apache,MySQL和PHP。或者，你也可以使用XAMP。



2. 安装和使用WAMP Server

你可以从http://www.wampserver.com/en/下载WAMP，安装完成之后，可以从开始->所有程序->WampServer->StartWampServer运行该程序。

在浏览器中输入http://localhost/来测试你的服务器是否安装成功。同样的，也可以打开http://localhost/phpmyadmin来检验phpmyadmin是否安装成功。

3. 创建和运行PHP项目

现在，你已经有一个能开发PHP和MYSQL项目的环境了。打开安装WAMP Server的文件夹（在我的电脑中，是C:\wamp\），打开www文件夹，为你的项目创建一个新的文件夹。你必须把项目中所有的文件放到这个文件夹中。

新建一个名为android_connect的文件夹，并新建一个php文件，命名为test.php，尝试输入一些简单的php代码（如下所示）。输入下面的代码后，打开http://localhost/android_connect/test.php，你会在浏览器中看到“Welcome,I am connecting Android to PHP,MySQL”（如果没有正确输入，请检查WAMP配置是否正确）

test.php

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

4. 创建MySQL数据库和表

在本教程中，我创建了一个简单的只有一张表的数据库。我会用这个表来执行一些示例操作。现在，请在浏览器中输入http://localhost/phpmyadmin/，并打开phpmyadmin。你可以用PhpMyAdmin工具创建数据库和表。

创建数据库和表：数据库名：androidhive，表：product

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 defaultnow(),
updated_at timestamp
);

5. 用PHP连接MySQL数据库

现在，真正的服务器端编程开始了。新建一个PHP类来连接MYSQL数据库。这个类的主要功能是打开数据库连接和在不需要时关闭数据库连接。

新建两个文件db_config.php,db_connect.php

db_config.php--------存储数据库连接变量

db_connect.php-------连接数据库的类文件

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

db_connect.php

<?php
/**
* A class file to connect to database
*/
classDB_CONNECT {
// constructor
function__construct() {
// connecting to database
$this->connect();
}
// destructor
function__destruct() {
// closing db connection
$this->close();
}
/**
* Function to connect with database
*/
functionconnect() {
// import database connection variables
require_once__DIR__ . '/db_config.php';
// Connecting to mysql database
$con= mysql_connect(DB_SERVER, DB_USER, DB_PASSWORD) ordie(mysql_error());
// Selecing database
$db= mysql_select_db(DB_DATABASE) ordie(mysql_error()) ordie(mysql_error());
// returing connection cursor
return$con;
}
/**
* Function to close db connection
*/
functionclose() {
// closing db connection
mysql_close();
}
}
?>

怎么调用：当你想连接MySQl数据库或者执行某些操作时，可以这样使用db_connect.php

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

6. 使用PHP执行基本CRUD操作

在这部分，我将讲述使用PHP对MySQL数据库执行基本CRUD（创建，读取，更新，删除）操作。

如果你是PHP和MySQL新手，我建议你可以先学习PHP和SQL基础知识。

6. a)在MYSQL中新建一行（创建一行新的产品）

在你的PHP项目中新建一个php文件，命名为create_product.php，并输入以下代码。该文件主要实现在products表中插入一个新的产品。

在下面的代码我使用POST来读取产品数据并把他们存储在products表中。

最后我会输出一些JSON返回值，以便返回给客户端（Android项目）

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= newDB_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;
$response["message"] = "Product successfully created.";
// echoing JSON response
echojson_encode($response);
} else{
// failed to insert row
$response["success"] = 0;
$response["message"] = "Oops! An error occurred.";
// echoing JSON response
echojson_encode($response);
}
} else{
// required field is missing
$response["success"] = 0;
$response["message"] = "Required field(s) is missing";
// echoing JSON response
echojson_encode($response);
}
?>

对于上面的代码，JSON的返回值会是：

当POST 参数丢失

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

当product成功创建

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

当插入数据时出现错误

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

6. b)从MySQL中读取一行信息（读取产品详细信息）

创建一个新的php文件，命名为get_product_details.php，写入以下代码。

该文件通过传递产品id作为POST参数获得单个产品的详细信息

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
$db= newDB_CONNECT();
// check for post data
if(isset($_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"], $product);
// echoing JSON response
echojson_encode($response);
} else{
// no product found
$response["success"] = 0;
$response["message"] = "No product found";
// echo no users JSON
echojson_encode($response);
}
} else{
// no product found
$response["success"] = 0;
$response["message"] = "No product found";
// echo no users JSON
echojson_encode($response);
}
} else{
// required field is missing
$response["success"] = 0;
$response["message"] = "Required field(s) is missing";
// echoing JSON response
echojson_encode($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)从MySQL读取所有行（读取所有产品信息）

我们需要用json数据在Android设备上显示所有的产品。

新建一个php文件，命名为get_all_products.php，写入以下代码。

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= newDB_CONNECT();
// get all products from products table
$result= mysql_query("SELECT *FROM products") ordie(mysql_error());
// check for empty result
if(mysql_num_rows($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
$response["success"] = 1;
// echoing JSON response
echojson_encode($response);
} else{
// no products found
$response["success"] = 0;
$response["message"] = "No products found";
// echo no users JSON
echojson_encode($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（更新产品详细信息）

新建一个php文件，命名为update_product.php。每一个产品通过pid标识。

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= newDB_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;
$response["message"] = "Product successfully updated.";
// echoing JSON response
echojson_encode($response);
} else{
}
} else{
// required field is missing
$response["success"] = 0;
$response["message"] = "Required field(s) is missing";
// echoing JSON response
echojson_encode($response);
}
?>

The json reponse of above code, when product is updated successfully
{
"success": 1,
"message": "Product successfully updated."
}

6. e)在MySQL中删除某一行（删除一个产品）

新建一个php文件，命名为delete_product.php。该文件主要功能是从数据库中删除一个产品。

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= newDB_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;
$response["message"] = "Product successfully deleted";
// echoing JSON response
echojson_encode($response);
} else{
// no product found
$response["success"] = 0;
$response["message"] = "No product found";
// echo no users JSON
echojson_encode($response);
}
} else{
// required field is missing
$response["success"] = 0;
$response["message"] = "Required field(s) is missing";
// echoing JSON response
echojson_encode($response);
}
?>

When product successfully deleted
{
"success": 1,
"message": "Product successfully deleted"
}
When product not found
{
"success": 0,
"message": "No product found"
}

到目前为止，我们为products表建立了一个简单的接口。服务器端编程已经完成了，接下来让我们开始真正的Android应用程序编程。

7. 新建一个Android应用程序

在Eclipse IDE中创建一个新项目，填写所需的细节信息。

1. 新建项目，在菜单中选择File->New->Android Project，把Activity类命名为MainScreenActivity

2. 打开AndroidManifest.xml，添加以下代码。我先在manifest文件中添加了所需的全部Activity类。同样需要添加INTERNET连接权限（非常重要）

AndroidManifest.xml

<?xmlversion="1.0"encoding="utf-8"?>
<manifestxmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.androidhive"
android:versionCode="1"
android:versionName="1.0">
<uses-sdkandroid: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>
<actionandroid:name="android.intent.action.MAIN"/>
<categoryandroid: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-permissionandroid:name="android.permission.INTERNET"/>
</manifest>

3. 在res->layout文件夹下新建一个xml文件，命名为mian_screen.xml。这个layout文件包含两个简单的按钮，通过这两个按钮可以查看所有产品和添加新产品。如下图所示

main_screen.xml

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns: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 -->
<Buttonandroid: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 -->
<Buttonandroid:id="@+id/btnCreateProduct"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Add New Products"
android:layout_marginTop="25dip"/>
</LinearLayout>

4. 打开MainScreenActivity.java为main_screen.xml文件里的两个按钮添加点击事件

MainScreenActivity.java

packagecom.example.androidhive;
importandroid.app.Activity;
importandroid.content.Intent;
importandroid.os.Bundle;
importandroid.view.View;
importandroid.widget.Button;
publicclassMainScreenActivity extendsActivity{
Button btnViewProducts;
Button btnNewProduct;
@Override
publicvoidonCreate(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(newView.OnClickListener() {
@Override
publicvoidonClick(View view) {
// Launching All products Activity
Intent i = newIntent(getApplicationContext(), AllProductsActivity.class);
startActivity(i);
}
});
// view products click event
btnNewProduct.setOnClickListener(newView.OnClickListener() {
@Override
publicvoidonClick(View view) {
// Launching create new product activity
Intent i = newIntent(getApplicationContext(), NewProductActivity.class);
startActivity(i);
}
});
}

5. 在ListView中显示所有产品（读取）

现在我们需要一个Activity来以列表的形式显示所有产品。如我们所知，使用ListView需要两个xml文件，一个是列表布局，另一个是单个的列表项布局。在res->layout文件夹下新建两个xml文件：all_product.xml和list_item.xml

all_product.xml

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns: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

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns: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. 新建一个名为AllProductActivity.java的类文件。

在下面的代码中，

首先，在后台AsyncTask线程中发送一个请求给get_all_products.php

然后，从get_all_products.php获取JSON格式的数据，我为json转换了格式（parser），并使其显示在ListView中。

如果没有找到产品，会跳转到AddNewProductActivity

AllProductActivity.java

packagecom.example.androidhive;
importjava.util.ArrayList;
importjava.util.HashMap;
importjava.util.List;
importorg.apache.http.NameValuePair;
importorg.json.JSONArray;
importorg.json.JSONException;
importorg.json.JSONObject;
importandroid.app.ListActivity;
importandroid.app.ProgressDialog;
importandroid.content.Intent;
importandroid.os.AsyncTask;
importandroid.os.Bundle;
importandroid.util.Log;
importandroid.view.View;
importandroid.widget.AdapterView;
importandroid.widget.AdapterView.OnItemClickListener;
importandroid.widget.ListAdapter;
importandroid.widget.ListView;
importandroid.widget.SimpleAdapter;
importandroid.widget.TextView;
publicclassAllProductsActivity extendsListActivity {
// Progress Dialog
privateProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = newJSONParser();
ArrayList<HashMap<String, String>> productsList;
// url to get all products list
privatestaticString url_all_products = "http://api.androidhive.info/android_connect/get_all_products.php";
// JSON Node names
privatestaticfinalString TAG_SUCCESS = "success";
privatestaticfinalString TAG_PRODUCTS = "products";
privatestaticfinalString TAG_PID = "pid";
privatestaticfinalString TAG_NAME = "name";
// products JSONArray
JSONArray products = null;
@Override
publicvoidonCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.all_products);
// Hashmap for ListView
productsList = newArrayList<HashMap<String, String>>();
// Loading products in Background Thread
newLoadAllProducts().execute();
// Get listview
ListView lv = getListView();
// on seleting single product
// launching Edit Product Screen
lv.setOnItemClickListener(newOnItemClickListener() {
@Override
publicvoidonItemClick(AdapterView<?> parent, View view,
intposition, longid) {
// getting values from selected ListItem
String pid = ((TextView) view.findViewById(R.id.pid)).getText()
.toString();
// Starting new intent
Intent in = newIntent(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
protectedvoidonActivityResult(intrequestCode, intresultCode, 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
* */
classLoadAllProducts extendsAsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protectedvoidonPreExecute() {
super.onPreExecute();
pDialog = newProgressDialog(AllProductsActivity.this);
pDialog.setMessage("Loading products. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products from url
* */
protectedString doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = newArrayList<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
intsuccess = json.getInt(TAG_SUCCESS);
if(success == 1) {
// products found
// Getting Array of Products
products = json.getJSONArray(TAG_PRODUCTS);
// looping through All Products
for(inti = 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 = newHashMap<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 = newIntent(getApplicationContext(),
NewProductActivity.class);
// Closing all previous activities
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
}
} catch(JSONException e) {
e.printStackTrace();
}
returnnull;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protectedvoidonPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(newRunnable() {
publicvoidrun() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = newSimpleAdapter(
AllProductsActivity.this, productsList,
R.layout.list_item, newString[] { TAG_PID,
TAG_NAME},
newint[] { R.id.pid, R.id.name });
// updating listview
setListAdapter(adapter);
}
});
}
}
}

7. 添加一个新产品（写入）

创建一个新的view和activity来向MySQL数据库添加新产品。

新建一个简单的表单，创建提供输入产品名称，价格和描述的EditText

add_product.xml

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!-- Name Label -->
<TextViewandroid: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 -->
<EditTextandroid: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 -->
<TextViewandroid: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 -->
<EditTextandroid: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 -->
<TextViewandroid: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 -->
<EditTextandroid: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 -->
<Buttonandroid:id="@+id/btnCreateProduct"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Create Product"/>
</LinearLayout>

8. 新建一个Activity来处理向MySQL数据库插入新产品。

新建名为NewProductActivity.java的文件，输入以下代码。在下面的代码中

首先，从EditText获得用户输入的产品数据，格式化成基本参数格式

然后，向create_product.php发送请求，通过HTTP POST创建一个新的产品

最后，从create_product.php获取json返回值，如果success值为1，新得到的列表中就加入了新增的产品。

NewProductActivity.java

packagecom.example.androidhive;
importjava.util.ArrayList;
importjava.util.List;
importorg.apache.http.NameValuePair;
importorg.apache.http.message.BasicNameValuePair;
importorg.json.JSONException;
importorg.json.JSONObject;
importandroid.app.Activity;
importandroid.app.ProgressDialog;
importandroid.content.Intent;
importandroid.os.AsyncTask;
importandroid.os.Bundle;
importandroid.util.Log;
importandroid.view.View;
importandroid.widget.Button;
importandroid.widget.EditText;
publicclassNewProductActivity extendsActivity {
// Progress Dialog
privateProgressDialog pDialog;
JSONParser jsonParser = newJSONParser();
EditText inputName;
EditText inputPrice;
EditText inputDesc;
// url to create new product
privatestaticString url_create_product = "http://api.androidhive.info/android_connect/create_product.php";
// JSON Node names
privatestaticfinalString TAG_SUCCESS = "success";
@Override
publicvoidonCreate(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(newView.OnClickListener() {
@Override
publicvoidonClick(View view) {
// creating new product in background thread
newCreateNewProduct().execute();
}
});
}
/**
* Background Async Task to Create new product
* */
classCreateNewProduct extendsAsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protectedvoidonPreExecute() {
super.onPreExecute();
pDialog = newProgressDialog(NewProductActivity.this);
pDialog.setMessage("Creating Product..");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Creating product
* */
protectedString doInBackground(String... args) {
String name = inputName.getText().toString();
String price = inputPrice.getText().toString();
String description = inputDesc.getText().toString();
// Building Parameters
List<NameValuePair> params = newArrayList<NameValuePair>();
params.add(newBasicNameValuePair("name", name));
params.add(newBasicNameValuePair("price", price));
params.add(newBasicNameValuePair("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{
intsuccess = json.getInt(TAG_SUCCESS);
if(success == 1) {
// successfully created product
Intent i = newIntent(getApplicationContext(), AllProductsActivity.class);
startActivity(i);
// closing this screen
finish();
} else{
// failed to create product
}
} catch(JSONException e) {
e.printStackTrace();
}
returnnull;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protectedvoidonPostExecute(String file_url) {
// dismiss the dialog once done
pDialog.dismiss();
}
}
}

9. 读取，更新，删除一项产品

你稍加注意就会发现，在AllProductsActivity.java中，选中列表的某一项，会进入EditProductActivity.java。

接下来新建一个名为edit_product,xml的xml文件，创建类似create_product,xml的表单。

edit_product,xml

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<!-- Name Label -->
<TextViewandroid: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 -->
<EditTextandroid: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 -->
<TextViewandroid: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 -->
<EditTextandroid: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 -->
<TextViewandroid: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 -->
<EditTextandroid: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"/>
<LinearLayoutandroid:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<!-- Button Create Product -->
<Buttonandroid:id="@+id/btnSave"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Save Changes"
android:layout_weight="1"/>
<!-- Button Create Product -->
<Buttonandroid:id="@+id/btnDelete"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Delete"
android:layout_weight="1"/>
</LinearLayout>
</LinearLayout>

10. 对应edit_product.xml新建EditProductActivity.java，并输入下列代码。

在以下代码中：

首先，从intent中读取发送给ListView的产品id(pid)

然后，向get_product_details.php发送请求，获得json格式的产品详细信息，把它显示在EditText中。

然后，当产品信息显示在表单中后，如果用户点击保存按钮，会向update_product.php发送另一个HTTP请求，更新数据库中的产品信息

如果用户点击删除按钮，将会向delete_product.php发送请求，该产品慧聪MySQL数据库中删除，ListView刷新后显示新的产品列表。

EditProductActivity.java

packagecom.example.androidhive;
importjava.util.ArrayList;
importjava.util.List;
importorg.apache.http.NameValuePair;
importorg.apache.http.message.BasicNameValuePair;
importorg.json.JSONArray;
importorg.json.JSONException;
importorg.json.JSONObject;
importandroid.app.Activity;
importandroid.app.ProgressDialog;
importandroid.content.Intent;
importandroid.os.AsyncTask;
importandroid.os.Bundle;
importandroid.util.Log;
importandroid.view.View;
importandroid.widget.Button;
importandroid.widget.EditText;
publicclassEditProductActivity extendsActivity {
EditText txtName;
EditText txtPrice;
EditText txtDesc;
EditText txtCreatedAt;
Button btnSave;
Button btnDelete;
String pid;
// Progress Dialog
privateProgressDialog pDialog;
// JSON parser class
JSONParser jsonParser = newJSONParser();
// single product url
privatestaticfinalString url_product_detials = "http://api.androidhive.info/android_connect/get_product_details.php";
// url to update product
privatestaticfinalString url_update_product = "http://api.androidhive.info/android_connect/update_product.php";
// url to delete product
privatestaticfinalString url_delete_product = "http://api.androidhive.info/android_connect/delete_product.php";
// JSON Node names
privatestaticfinalString TAG_SUCCESS = "success";
privatestaticfinalString TAG_PRODUCT = "product";
privatestaticfinalString TAG_PID = "pid";
privatestaticfinalString TAG_NAME = "name";
privatestaticfinalString TAG_PRICE = "price";
privatestaticfinalString TAG_DESCRIPTION = "description";
@Override
publicvoidonCreate(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
newGetProductDetails().execute();
// save button click event
btnSave.setOnClickListener(newView.OnClickListener() {
@Override
publicvoidonClick(View arg0) {
// starting background task to update product
newSaveProductDetails().execute();
}
});
// Delete button click event
btnDelete.setOnClickListener(newView.OnClickListener() {
@Override
publicvoidonClick(View arg0) {
// deleting product in background thread
newDeleteProduct().execute();
}
});
}
/**
* Background Async Task to Get complete product details
* */
classGetProductDetails extendsAsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protectedvoidonPreExecute() {
super.onPreExecute();
pDialog = newProgressDialog(EditProductActivity.this);
pDialog.setMessage("Loading product details. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Getting product details in background thread
* */
protectedString doInBackground(String... params) {
// updating UI from Background Thread
runOnUiThread(newRunnable() {
publicvoidrun() {
// Check for success tag
intsuccess;
try{
// Building Parameters
List<NameValuePair> params = newArrayList<NameValuePair>();
params.add(newBasicNameValuePair("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();
}
}
});
returnnull;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protectedvoidonPostExecute(String file_url) {
// dismiss the dialog once got all details
pDialog.dismiss();
}
}
/**
* Background Async Task to Save product Details
* */
classSaveProductDetails extendsAsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protectedvoidonPreExecute() {
super.onPreExecute();
pDialog = newProgressDialog(EditProductActivity.this);
pDialog.setMessage("Saving product ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Saving product
* */
protectedString 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 = newArrayList<NameValuePair>();
params.add(newBasicNameValuePair(TAG_PID, pid));
params.add(newBasicNameValuePair(TAG_NAME, name));
params.add(newBasicNameValuePair(TAG_PRICE, price));
params.add(newBasicNameValuePair(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{
intsuccess = 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();
}
returnnull;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protectedvoidonPostExecute(String file_url) {
// dismiss the dialog once product uupdated
pDialog.dismiss();
}
}
/*****************************************************************
* Background Async Task to Delete Product
* */
classDeleteProduct extendsAsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protectedvoidonPreExecute() {
super.onPreExecute();
pDialog = newProgressDialog(EditProductActivity.this);
pDialog.setMessage("Deleting Product...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Deleting product
* */
protectedString doInBackground(String... args) {
// Check for success tag
intsuccess;
try{
// Building Parameters
List<NameValuePair> params = newArrayList<NameValuePair>();
params.add(newBasicNameValuePair("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();
}
returnnull;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protectedvoidonPostExecute(String file_url) {
// dismiss the dialog once product deleted
pDialog.dismiss();
}
}
}

11. JSONParser类

我用一个JSONParser类从URL获得JSON格式的数据。这个类支持两种http请求，GET和POST方法从URL获取JSON数据

JSONParser.java

packagecom.example.androidhive;
importjava.io.BufferedReader;
importjava.io.IOException;
importjava.io.InputStream;
importjava.io.InputStreamReader;
importjava.io.UnsupportedEncodingException;
importjava.util.List;
importorg.apache.http.HttpEntity;
importorg.apache.http.HttpResponse;
importorg.apache.http.NameValuePair;
importorg.apache.http.client.ClientProtocolException;
importorg.apache.http.client.entity.UrlEncodedFormEntity;
importorg.apache.http.client.methods.HttpGet;
importorg.apache.http.client.methods.HttpPost;
importorg.apache.http.client.utils.URLEncodedUtils;
importorg.apache.http.impl.client.DefaultHttpClient;
importorg.json.JSONException;
importorg.json.JSONObject;
importandroid.util.Log;
publicclassJSONParser {
staticInputStream is = null;
staticJSONObject jObj = null;
staticString json = "";
// constructor
publicJSONParser() {
}
// function get json from url
// by making HTTP POST or GET mehtod
publicJSONObject 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 = newDefaultHttpClient();
HttpPost httpPost = newHttpPost(url);
httpPost.setEntity(newUrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}elseif(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = newDefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?"+ paramString;
HttpGet httpGet = newHttpGet(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 = newBufferedReader(newInputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = newStringBuilder();
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 = newJSONObject(json);
} catch(JSONException e) {
Log.e("JSON Parser", "Error parsing data "+ e.toString());
}
// return JSON String
returnjObj;
}
}

到这里，本教程就结束了。

运行你的代码，测试一下程序吧。你可能会遇到不少错误，经常使用LogCat来调试你的项目。

如果你不能解决那些错误，请在此留言。

原文链接：http://www.androidhive.info/2012/05/how-to-connect-android-with-php-mysql/