在本章中，我们将解释如何将PHP和MYSQL与Android应用程序集成.如果您有一个Web服务器，并且想要在Android应用程序上访问它的数据，这非常有用.
MYSQL用作Web服务器上的数据库，PHP用于获取数据来自数据库.我们的应用程序将使用必要的参数与PHP页面进行通信，PHP将联系MYSQL数据库并获取结果并将结果返回给我们.
使用这个简单的脚本可以轻松创建MYSQL数据库. CREATE DATABASE 语句创建数据库.
<?php
$con=mysqli_connect("example.com","username","password");
$sql="CREATE DATABASE my_db";
if (mysqli_query($con,$sql)) {
echo "Database my_db created successfully";
}
?>创建数据库后，是时候在数据库中创建一些表了. CREATE TABLE 语句创建数据库.
<?php
$con=mysqli_connect("example.com","username","password","my_db");
$sql="CREATE TABLE table1(Username CHAR(30),Password CHAR(30),Role CHAR(30))";
if (mysqli_query($con,$sql)) {
echo "Table have been created successfully";
}
?>创建数据库和表格时.现在是时候将一些数据插入表中了. 插入到语句创建数据库.
<?php
$con=mysqli_connect("example.com","username","password","my_db");
$sql="INSERT INTO table1 (FirstName, LastName, Age) VALUES ('admin', 'admin','adminstrator')";
if (mysqli_query($con,$sql)) {
echo "Values have been inserted successfully";
}
?>PHP也用于从mysql数据库中获取记录创建.为了获取记录，必须将一些信息传递给PHP页面，了解要提取的记录.
传递信息的第一种方法是通过GET方法，其中 $ _ GET 使用命令.变量在url中传递并获取记录.它的语法在下面和下面给出;
<?php
$con=mysqli_connect("example.com","username","password","database name");
if (mysqli_connect_errno($con)) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$username = $_GET['username'];
$password = $_GET['password'];
$result = mysqli_query($con,"SELECT Role FROM table1 where Username='$username'
and Password='$password'");
$row = mysqli_fetch_array($result);
$data = $row[0];
if($data){
echo $data;
}
mysqli_close($con);
?>第二种方法是使用POST方法.上述脚本中唯一的变化是用 $ _ POST 替换$ _GET.在Post方法中，变量不通过URL传递.
有两种方法可以通过PHP页面连接到MYSQL.第一个叫做获取方法.我们将使用 HttpGet 和 HttpClient 类进行连接.他们的语法在下面和下面给出;
URL url = new URL(link); HttpClient client = new DefaultHttpClient(); HttpGet request = new HttpGet(); request.setURI(new URI(link));
之后你需要调用HttpClient类的 execute 方法并在HttpResponse对象中接收它.之后，您需要打开流来接收数据.
HttpResponse response = client.execute(request); BufferedReader in = new BufferedReader (new InputStreamReader(response.getEntity().getContent()));
在Post方法中， URLEncoder ，
URL url = new URL(link);
String data = URLEncoder.encode("username"，"UTF-8")
+"="+ URLEncoder.encode(username，"UTF-8");
data + ="&"+ URLEncoder.encode("password"，"UTF-8")
+"="+ URLEncoder.encode(password，"UTF-8");
URLConnection conn = url.openConnection();您需要做的最后一件事就是将此数据写入链接.写完之后，你需要打开流来接收响应的数据.
URL url = new URL(link);
String data = URLEncoder.encode("username", "UTF-8")
+ "=" + URLEncoder.encode(username, "UTF-8");
data += "&" + URLEncoder.encode("password", "UTF-8")
+ "=" + URLEncoder.encode(password, "UTF-8");
URLConnection conn = url.openConnection();以下示例是通过PHP页面将Android应用程序与MYSQL数据库连接的完整示例.它创建了一个允许您使用GET和POST方法登录的基本应用程序.
在此示例中，名称为数据库temp已在000webhost.com上创建.在该数据库中，创建了一个名为table1的表.该表有三个字段. (用户名，密码，角色).该表只有一个记录("admin"，"admin"，"administrator").
下面给出了php页面，它通过post方法获取参数.
<?php
$con=mysqli_connect("mysql10.000webhost.com","username","password","db_name");
if (mysqli_connect_errno($con)) {
echo "Failed to connect to MySQL: " . mysqli_connect_error();
}
$username = $_POST['username'];
$password = $_POST['password'];
$result = mysqli_query($con,"SELECT Role FROM table1 where
Username='$username' and Password='$password'");
$row = mysqli_fetch_array($result);
$data = $row[0];
if($data){
echo $data;
}
mysqli_close($con);
?>要试验此示例，您需要在无线互联网上的实际设备上运行此功能已连接.
| 步骤 | 描述 |
|---|---|
| 1 | 您将使用Android studio IDE创建一个Android应用程序，并在com.example.phpmysql包下将其命名为PHPMYSQL. |
| 2 | 修改src/MainActivity.java文件以添加活动代码. |
| 3 | 创建src/SiginActivity.java文件以添加PHPMYSQL代码. |
| 4 | 修改布局XML文件res/layout/activity_main.xml如果需要，添加任何GUI组件. |
| 5 | 修改res/values/string.xml文件并添加必要的字符串组件. |
| 6 | 修改Andro idManifest.xml添加必要的权限. |
| 7 | 运行应用程序选择一个正在运行的Android设备并在其上安装应用程序并验证结果. |
这是src/com.example.phpmysql/MainActivity.java
package com.example.phpmysql;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends Activity {
private EditText usernameField,passwordField;
private TextView status,role,method;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
usernameField = (EditText)findViewById(R.id.editText1);
passwordField = (EditText)findViewById(R.id.editText2);
status = (TextView)findViewById(R.id.textView6);
role = (TextView)findViewById(R.id.textView7);
method = (TextView)findViewById(R.id.textView9);
}
public void login(View view){
String username = usernameField.getText().toString();
String password = passwordField.getText().toString();
method.setText("Get Method");
new SigninActivity(this,status,role,0).execute(username,password);
}
public void loginPost(View view){
String username = usernameField.getText().toString();
String password = passwordField.getText().toString();
method.setText("Post Method");
new SigninActivity(this,status,role,1).execute(username,password);
}
}以下是 src/com.example.phpmysql/SigninActivity.java .
package com.example.phpmysql;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.URI;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.TextView;
public class SigninActivity extends AsyncTask{
private TextView statusField,roleField;
private Context context;
private int byGetOrPost = 0;
//flag 0 means get and 1 means post.(By default it is get.)
public SigninActivity(Context context,TextView statusField,TextView roleField,int flag) {
this.context = context;
this.statusField = statusField;
this.roleField = roleField;
byGetOrPost = flag;
}
protected void onPreExecute(){
}
@Override
protected String doInBackground(String... arg0) {
if(byGetOrPost == 0){ //means by Get Method
try{
String username = (String)arg0[0];
String password = (String)arg0[1];
String link = "http://myphpmysqlweb.hostei.com/login.php?username="+username+"& password="+password;
URL url = new URL(link);
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet();
request.setURI(new URI(link));
HttpResponse response = client.execute(request);
BufferedReader in = new BufferedReader(new
InputStreamReader(response.getEntity().getContent()));
StringBuffer sb = new StringBuffer("");
String line="";
while ((line = in.readLine()) != null) {
sb.append(line);
break;
}
in.close();
return sb.toString();
} catch(Exception e){
return new String("Exception: " + e.getMessage());
}
} else{
try{
String username = (String)arg0[0];
String password = (String)arg0[1];
String link="http://myphpmysqlweb.hostei.com/loginpost.php";
String data = URLEncoder.encode("username", "UTF-8") + "=" +
URLEncoder.encode(username, "UTF-8");
data += "&" + URLEncoder.encode("password", "UTF-8") + "=" +
URLEncoder.encode(password, "UTF-8");
URL url = new URL(link);
URLConnection conn = url.openConnection();
conn.setDoOutput(true);
OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
wr.write( data );
wr.flush();
BufferedReader reader = new BufferedReader(new
InputStreamReader(conn.getInputStream()));
StringBuilder sb = new StringBuilder();
String line = null;
// Read Server Response
while((line = reader.readLine()) != null) {
sb.append(line);
break;
}
return sb.toString();
} catch(Exception e){
return new String("Exception: " + e.getMessage());
}
}
}
@Override
protected void onPostExecute(String result){
this.statusField.setText("Login Successful");
this.roleField.setText(result);
}
}将以下内容添加到 build.gradle 并重建整个项目.
android {
useLibrary 'org.apache.http.legacy'
}以下是 activity_main.xml 的内容.
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" > <EditText android:id="@+id/editText2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignRight="@+id/editText1" android:layout_below="@+id/editText1" android:layout_marginTop="25dp" android:ems="10" android:inputType="textPassword" > </EditText> <EditText android:id="@+id/editText1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentRight="true" android:layout_alignParentTop="true" android:layout_marginTop="44dp" android:ems="10" > <requestFocus android:layout_width="wrap_content" /> </EditText> <TextView android:id="@+id/textView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@+id/editText1" android:layout_alignParentLeft="true" android:text="@string/Username" /> <TextView android:id="@+id/textView3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:layout_centerHorizontal="true" android:text="@string/App" android:textAppearance="?android:attr/textAppearanceLarge" /> <TextView android:id="@+id/textView7" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@+id/textView5" android:layout_alignLeft="@+id/textView6" android:text="@string/Role" android:textAppearance="?android:attr/textAppearanceMedium" android:textSize="10sp" /> <TextView android:id="@+id/textView5" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@+id/textView6" android:layout_marginTop="27dp" android:layout_toLeftOf="@+id/editText1" android:text="@string/LoginRole" /> <TextView android:id="@+id/textView8" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_above="@+id/textView6" android:layout_alignLeft="@+id/textView5" android:layout_marginBottom="27dp" android:text="@string/method" /> <TextView android:id="@+id/textView4" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignLeft="@+id/textView8" android:layout_below="@+id/button1" android:layout_marginTop="86dp" android:text="@string/LoginStatus" /> <TextView android:id="@+id/textView6" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignTop="@+id/textView4" android:layout_centerHorizontal="true" android:text="@string/Status" android:textAppearance="?android:attr/textAppearanceMedium" android:textSize="10sp" /> <TextView android:id="@+id/textView9" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@+id/textView8" android:layout_alignLeft="@+id/textView6" android:text="@string/Choose" android:textAppearance="?android:attr/textAppearanceMedium" android:textSize="10sp" /> <Button android:id="@+id/button2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_centerVertical="true" android:layout_toRightOf="@+id/textView6" android:onClick="loginPost" android:text="@string/LoginPost" /> <Button android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBaseline="@+id/button2" android:layout_alignBottom="@+id/button2" android:layout_alignLeft="@+id/textView2" android:onClick="login" android:text="@string/LoginGet" /> <TextView android:id="@+id/textView2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBaseline="@+id/editText2" android:layout_alignBottom="@+id/editText2" android:layout_alignParentLeft="true" android:text="@string/Password" /> </RelativeLayout>
以下是 Strings.xml 的内容.
<?xml version="1.0" encoding="utf-8"?> <resources> <string name="app_name">PHPMYSQL</string> <string name="action_settings">Settings</string> <string name="hello_world">Hello world!</string> <string name="Username">Username</string> <string name="Password">Password</string> <string name="LoginGet">Login - Get</string> <string name="LoginPost">Login - Post</string> <string name="App">Login Application</string> <string name="LoginStatus">Login Status</string> <string name="LoginRole">Login Role</string> <string name="Status">Not login</string> <string name="Role">Not assigned</string> <string name="method">Login Method</string> <string name="Choose">Choose Method</string> </resources>
以下是 AndroidManifest.xml 的内容.
<?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.example.phpmysql" > <uses-permission android:name="android.permission.INTERNET"/> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <application android:allowBackup="true" android:icon="@drawable/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name="com.example.phpmysql.MainActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
让我们尝试运行PHPMYSQL应用程序.我假设您已将实际的Android移动设备与计算机相关联.要从Android工作室运行应用程序，请打开项目的一个活动文件，然后单击运行
icon从工具栏.在开始申请之前，Android studio将显示以下窗口，以选择您要运行Android应用程序的选项.
选择您的移动设备作为选项，然后检查您的移动设备，它将显示以下屏幕 :
现在只需输入您的用户名和密码即可.在我的情况下，我输入admin作为用户名和密码.它显示在图中 :
现在按下"获取"按钮并等待几秒钟，将会下载响应并显示给您.在这种情况下，响应是在管理员作为用户名和密码的情况下获取的ROLE.它如下图所示 :
现在再次按下POST按钮，会出现相同的结果.它如下图所示 :
