Android使用PHP连接MySQL

时间：2014-11-16 10:48:52

标签： php android mysql

我正在尝试使用MySQL连接我的第一个Android应用程序，我谷歌很多，并找到一些教程和类似的东西。基于它们我有这个代码：

package com.example.helloworld;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.apache.http.HttpEntity;
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.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

    String name;
    String id;
    InputStream is=null;
    String result=null;
    String line=null;
    int code;

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

        final EditText e_id=(EditText) findViewById(R.id.editText1);
        final EditText e_name=(EditText) findViewById(R.id.editText2);
        Button insert=(Button) findViewById(R.id.button1);

        insert.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            id = e_id.getText().toString();
            name = e_name.getText().toString();

            insert();
        }
    });
    }

    public void insert()
    {
        ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

    nameValuePairs.add(new BasicNameValuePair("id",id));
    nameValuePairs.add(new BasicNameValuePair("name",name));

        try
        {
        HttpClient httpclient = new DefaultHttpClient();
            HttpPost httppost = new HttpPost("http://localhost/xampp/android_connect/index.php");
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
            HttpResponse response = httpclient.execute(httppost); 
            HttpEntity entity = response.getEntity();
            is = entity.getContent();
            Log.e("pass 1", "connection success ");
    }
        catch(Exception e)
    {
            Log.e("Fail 1", e.toString());
            Toast.makeText(getApplicationContext(), "Invalid IP Address",
            Toast.LENGTH_LONG).show();
    }     

        try
        {
            BufferedReader reader = new BufferedReader
            (new InputStreamReader(is,"iso-8859-1"),8);
            StringBuilder sb = new StringBuilder();
            while ((line = reader.readLine()) != null)
        {
                sb.append(line + "\n");
            }
            is.close();
            result = sb.toString();
        Log.e("pass 2", "connection success ");
    }
        catch(Exception e)
    {
            Log.e("Fail 2", e.toString());
    }     

    try
    {
            JSONObject json_data = new JSONObject(result);
            code=(json_data.getInt("code"));

            if(code==1)
            {
        Toast.makeText(getBaseContext(), "Inserted Successfully",
            Toast.LENGTH_SHORT).show();
            }
            else
            {
         Toast.makeText(getBaseContext(), "Sorry, Try Again",
            Toast.LENGTH_LONG).show();
            }
    }
    catch(Exception e)
    {
            Log.e("Fail 3", e.toString());
    }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }    
}

我无法看到任何错误或其他任何内容但是当我尝试加载它时会说：“无效的IP地址” （来自catch {}的错误消息）。 我尝试研究哪里可能有问题，在LogCat中我发现了这个错误：

11-16 10:39:10.036: I/ActivityManager(150): Start proc com.example.helloworld for activity com.example.helloworld/.MainActivity: pid=612 uid=10045 gids={3003, 1028}
11-16 10:39:10.386: E/Trace(612): error opening trace file: No such file or directory (2)
11-16 10:39:10.966: D/gralloc_goldfish(612): Emulator without GPU emulation detected.
11-16 10:39:11.016: I/ActivityManager(150): Displayed com.example.helloworld/.MainActivity: +1s32ms
11-16 10:39:11.066: I/Choreographer(150): Skipped 34 frames!  The application may be doing too much work on its main thread.
11-16 10:39:18.945: E/Fail 1(612): android.os.NetworkOnMainThreadException
11-16 10:39:18.975: E/Fail 2(612): java.lang.NullPointerException
11-16 10:39:18.975: E/Fail 3(612): java.lang.NullPointerException
11-16 10:39:19.195: D/dalvikvm(612): GC_CONCURRENT freed 191K, 4% free 6229K/6471K, paused 17ms+65ms, total 206ms
11-16 10:39:20.065: E/Fail 1(612): android.os.NetworkOnMainThreadException
11-16 10:39:20.075: E/Fail 2(612): java.lang.NullPointerException
11-16 10:39:20.075: E/Fail 3(612): java.lang.NullPointerException
11-16 10:39:20.645: E/Fail 1(612): android.os.NetworkOnMainThreadException
11-16 10:39:20.645: E/Fail 2(612): java.lang.NullPointerException
11-16 10:39:20.645: E/Fail 3(612): java.lang.NullPointerException
11-16 10:39:21.055: E/Fail 1(612): android.os.NetworkOnMainThreadException
11-16 10:39:21.065: E/Fail 2(612): java.lang.NullPointerException
11-16 10:39:21.065: E/Fail 3(612): java.lang.NullPointerException
11-16 10:39:21.535: E/Fail 1(612): android.os.NetworkOnMainThreadException
11-16 10:39:21.545: E/Fail 2(612): java.lang.NullPointerException
11-16 10:39:21.545: E/Fail 3(612): java.lang.NullPointerException
11-16 10:39:21.728: E/Fail 1(612): android.os.NetworkOnMainThreadException
11-16 10:39:21.735: E/Fail 2(612): java.lang.NullPointerException
11-16 10:39:21.735: E/Fail 3(612): java.lang.NullPointerException
11-16 10:39:21.925: E/Fail 1(612): android.os.NetworkOnMainThreadException
11-16 10:39:21.925: E/Fail 2(612): java.lang.NullPointerException
11-16 10:39:21.925: E/Fail 3(612): java.lang.NullPointerException
11-16 10:39:22.535: I/Choreographer(612): Skipped 37 frames!  The application may be doing too much work on its main thread.
: E/(): Device disconnected: 1
: E/(): Device disconnected

Especialy我看看找不到目录，我尝试在我的borowser中打开相同的地址，我打开它没有问题。有人能告诉我我做错了什么吗？

由于

3 个答案:

答案 0 :(得分：2)

localhost指向设备本身;所以你可以尝试以下方法：

  • 如果您是在自己的网络上运行此测试，请尝试键入您的本地IP 而不是localhost，例如 http://192.168.0.123

  • 请尝试使用http://10.0.2.2代替localhost，在设备上的浏览器中输入，然后查看它是否正常连接。

同时查看this question。

Reference for 10.0.2.2

关于NetworkOnMainThreadException

您尝试在应用程序的主线程上进行网络操作，这可能会导致严重延迟和无法预测的结果 。

您应始终使用AsyncTask进行网络操作。请参阅android docs中的this article。

以下是一个示例用法;

您的AsyncTask应如下所示：

 private class DownloadWebpageTask extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... urls) {

        // params comes from the execute() call: params[0] is the url.
        try {

            // Initialize your parameters
            ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
            nameValuePairs.add(new BasicNameValuePair("id",urls[1]));
            nameValuePairs.add(new BasicNameValuePair("name",urls[2]));         

            // Make your HTTP Request
            HttpClient httpclient = new DefaultHttpClient();
            HttpPost httppost = new HttpPost(urls[0]);
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
            HttpResponse response = httpclient.execute(httppost); 
            HttpEntity entity = response.getEntity();
            is = entity.getContent();

            // Read the response
            BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
            StringBuilder sb = new StringBuilder();
            while ((line = reader.readLine()) != null) {
             sb.append(line + "\n");
            }
            is.close();
            result = sb.toString();

            // Return the response.
            return result;
        } catch (IOException e) {
            return "Unable to retrieve web page. URL may be invalid.";
        }
    }

    // onPostExecute gets the results of the AsyncTask.
    @Override
    protected void onPostExecute(String result) {

        // Read your response into a JSONObject and do stuff...
        JSONObject json_data = new JSONObject(result);
        code=(json_data.getInt("code"));
        if(code==1)
        {
            Toast.makeText(getBaseContext(), "Inserted Successfully", Toast.LENGTH_SHORT).show();
        }
        else
        {
            Toast.makeText(getBaseContext(), "Sorry, Try Again", Toast.LENGTH_LONG).show();
        }
   }
}

您可以像以下一样使用它：

// Params : url, id, name
new DownloadWebpageTask().execute("http://10.0.2.2/xampp/android_connect/index.php", "12345", "Foo Bar");

以下是您的代码应如下所示的完整示例：

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.apache.http.HttpEntity;
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.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONObject;
import android.os.Bundle;
import android.app.Activity;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

    String name;
    String id;
    InputStream is=null;
    String result=null;
    String line=null;
    int code;

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

        final EditText e_id=(EditText) findViewById(R.id.editText1);
        final EditText e_name=(EditText) findViewById(R.id.editText2);
        Button insert=(Button) findViewById(R.id.button1);

        insert.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                id = e_id.getText().toString();
                name = e_name.getText().toString();

                insert();
            }
        });
    }

    public void insert()
    {
        new DownloadWebpageTask().execute("http://10.0.2.2/xampp/android_connect/index.php", id, name);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    private class DownloadWebpageTask extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... urls) {

        // params comes from the execute() call: params[0] is the url.
        try {
            // Initialize your parameters
            ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
            nameValuePairs.add(new BasicNameValuePair("id",urls[1]));
            nameValuePairs.add(new BasicNameValuePair("name",urls[2]));         

            // Make your HTTP Request
            HttpClient httpclient = new DefaultHttpClient();
            HttpPost httppost = new HttpPost(urls[0]);
            httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
            HttpResponse response = httpclient.execute(httppost); 
            HttpEntity entity = response.getEntity();
            is = entity.getContent();

            // Read the response
            BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
            StringBuilder sb = new StringBuilder();
            while ((line = reader.readLine()) != null) {
             sb.append(line + "\n");
            }
            is.close();
            result = sb.toString();

            // Return the response.
            return result;
        } catch (IOException e) {
            return "Unable to retrieve web page. URL may be invalid.";
        }
    }

    // onPostExecute gets the results of the AsyncTask.
    @Override
    protected void onPostExecute(String result) {

        // Read your response into a JSONObject and do stuff...
        JSONObject json_data = new JSONObject(result);
        code=(json_data.getInt("code"));
        if(code==1)
        {
            Toast.makeText(getBaseContext(), "Inserted Successfully", Toast.LENGTH_SHORT).show();
        }
        else
        {
            Toast.makeText(getBaseContext(), "Sorry, Try Again", Toast.LENGTH_LONG).show();
        }
   }
}
}

答案 1 :(得分：1)

我认为你有两个问题：

  1. 将localhost更改为您机器的IP地址。
  2. 您正在UI线程上进行网络调用，这对性能不利。您可以使用AsyncTask代替或使用像Retrofit这样的库！ ;）

答案 2 :(得分：0)

你做错了。试试10.0.2.2/android_connect/index.php。 10.0.2.2重定向到xampp / htdoc /文件夹。

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