如何从Android发送字符串到PHP

Question

i was trying to create an online apps. I would like to send a string from my apps to my PHP script, but it ended up with the php doesn't receive any string from my apps, which means the PhP will echo back NULL. I have been doing research online and searching for solution, but none of them worked.

Below is my MainActivity.java code:

package my.com.tutionathome.calvinlau.testserver;

import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends Activity {
    Button b;
    EditText et;
    TextView tv;
    HttpPost httppost;
    StringBuffer buffer;
    HttpResponse response;
    HttpClient httpclient;
    List<NameValuePair> nameValuePairs;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        b = (Button)findViewById(R.id.Button01);
        et= (EditText)findViewById(R.id.EditText01);
        tv= (TextView)findViewById(R.id.tv);

        b.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {

                final ProgressDialog p = new ProgressDialog(v.getContext()).show(v.getContext(),"Waiting for Server", "Accessing Server");
                Thread thread = new Thread()
                {
                    @Override
                    public void run() {
                        try{

                            httpclient=new DefaultHttpClient();
                            httppost= new            HttpPost("http://10.0.0.2/my_folder_inside_htdocs/connection.php"); // make sure the url is correct.
                            //add your data
                            nameValuePairs = new ArrayList<NameValuePair>(1);
                            // Always use the same variable name for posting i.e the android side variable name and php side variable name should be similar,
                            nameValuePairs.add(new BasicNameValuePair("username",et.getText().toString().trim()));  // $"username" = $_POST['username'];
                            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
                            //Execute HTTP Post Request
                            response=httpclient.execute(httppost);

                            ResponseHandler<String> responseHandler = new BasicResponseHandler();
                            final String response = httpclient.execute(httppost, responseHandler);
                            System.out.println("Response : " + response);
                            runOnUiThread(new Runnable() {
                                public void run() {
                                    p.dismiss();
                                    tv.setText("Response from PHP : " + response);
                                }
                            });

                        }catch(Exception e){

                            runOnUiThread(new Runnable() {
                                public void run() {
                                    p.dismiss();
                                }
                            });
                            System.out.println("Exception : " + e.getMessage());
                        }
                    }
                };

                thread.start();


            }
        });
    }
}

And my php code:

<?php
        // put your code here
        $hostname_localhost ="localhost";
    $database_localhost ="android";
    $username_localhost ="root";
    $password_localhost ="";
    $localhost = mysql_connect($hostname_localhost,$username_localhost,$password_localhost)
    or
    trigger_error(mysql_error(),E_USER_ERROR);

    mysql_select_db($database_localhost, $localhost);

    $username = $_POST['username'];
    $password = $_POST['password'];
    $query_search = "select Email, Username from tblmember where Username = '".$username."' AND Email = '".$password. "'";
    $query_exec = mysql_query($query_search) or die(mysql_error());
    $rows = mysql_num_rows($query_exec);

    if($username == NULL){
        echo "NULL";
    }else{
        echo $username; 
    }
        ?>

This is my Android Manifest :

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="my.com.tutionathome.calvinlau.testserver">
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

Answer 1

有很多库来促进这一点，节省了许多代码行，我特别建议改造 。

Answer 2

Try this Code.

AysncyTask

private class AysncyTask extends AsyncTask<Void,Void,Void>
    {
        private ProgressDialog regDialog=null;
        @Override
        protected void onPreExecute()
        {
            super.onPreExecute();
            regDialog=new ProgressDialog(this);
            regDialog.setTitle(getResources().getString(R.string.app_name));
            regDialog.setMessage(getResources().getString(R.string.app_pleasewait));
            regDialog.setIndeterminate(true);
            regDialog.setCancelable(true);
            regDialog.show();
        }       
        @Override
        protected Void doInBackground(Void... params) {
            try 
            {
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();



                        postParameters.add(new BasicNameValuePair("username",
                                et.getText().toString().trim()));

  postParameters.add(new BasicNameValuePair("password",
                                etpass.getText().toString().trim()));





                        String response = null;
                        try {
                            response = SimpleHttpClient
                                    .executeHttpPost("http://10.0.0.2/my_folder_inside_htdocs/connection.php",
                                            postParameters);
                             res = response.toString();

                             return res;

                        } catch (Exception e) {
                            e.printStackTrace();
                            errorMsg = e.getMessage();
                        }
                    }
                }).start();
                try {
                    Thread.sleep(3000);


                //  error.setText(resp);
                    if (null != errorMsg && !errorMsg.isEmpty()) {

                    }
                } catch (Exception e) {
                }

            } 
            catch (Exception e) 
            {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(Void result)
        {
            super.onPostExecute(result);
            if(regDialog!=null)
            {

                regDialog.dismiss();

            //do you code here you want

                }

  // do what u do
    }

SimpleHttpClient.java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URI;
import java.util.ArrayList;

import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
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.conn.params.ConnManagerParams;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.params.HttpParams;

public class SimpleHttpClient {
 /** The time it takes for our client to timeout */
    public static final int HTTP_TIMEOUT = 30 * 1000; // milliseconds

    /** Single instance of our HttpClient */
    private static HttpClient mHttpClient;

    /**
     * Get our single instance of our HttpClient object.
     *
     * @return an HttpClient object with connection parameters set
     */
    private static HttpClient getHttpClient() {
    if (mHttpClient == null) {
        mHttpClient = new DefaultHttpClient();
        final HttpParams params = mHttpClient.getParams();
        HttpConnectionParams.setConnectionTimeout(params, HTTP_TIMEOUT);
        HttpConnectionParams.setSoTimeout(params, HTTP_TIMEOUT);
        ConnManagerParams.setTimeout(params, HTTP_TIMEOUT);
    }
    return mHttpClient;
    }

    public static String executeHttpPost(String url, ArrayList<NameValuePair> postParameters) throws Exception {
    BufferedReader in = null;
    try {
        HttpClient client = getHttpClient();
        HttpPost request = new HttpPost(url);
        UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(postParameters);
        request.setEntity(formEntity);
        HttpResponse response = client.execute(request);
        in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

        StringBuffer sb = new StringBuffer("");
        String line = "";
        String NL = System.getProperty("line.separator");
        while ((line = in.readLine()) != null) {
        sb.append(line + NL);
        }
        in.close();

        String result = sb.toString();
        return result;
    }
    finally {
        if (in != null) {
        try {
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        }
    }
    }


    public static String executeHttpatch(String url, ArrayList<NameValuePair> postParameters) throws Exception {
    BufferedReader in = null;
    try {
        HttpClient client = getHttpClient();
        HttpPost request = new HttpPost(url);
        UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(postParameters);
        request.setEntity(formEntity);
        HttpResponse response = client.execute(request);
        in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

        StringBuffer sb = new StringBuffer("");
        String line = "";
        String NL = System.getProperty("line.separator");
        while ((line = in.readLine()) != null) {
        sb.append(line + NL);
        }
        in.close();

        String result = sb.toString();
        return result;
    }
    finally {
        if (in != null) {
        try {
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        }
    }
    }

    /**
     * Performs an HTTP GET request to the specified url.
     *
     * @param url The web address to post the request to
     * @return The result of the request
     * @throws Exception
     */
    public static String executeHttpGet(String url) throws Exception {
    BufferedReader in = null;
    try {
        HttpClient client = getHttpClient();
        HttpGet request = new HttpGet();
        request.setURI(new URI(url));
        HttpResponse response = client.execute(request);
        in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));

        StringBuffer sb = new StringBuffer("");
        String line = "";
        String NL = System.getProperty("line.separator");
        while ((line = in.readLine()) != null) {
        sb.append(line + NL);
        }
        in.close();

        String result = sb.toString();
        return result;
    }
    finally {
        if (in != null) {
        try {
            in.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        }
    }
    }
}