php - 通过json在数据库中插入行不起作用

Question

我遵循了本教程 http://www.androidhive.info/2012/05/how-to-connect-android-with-php-mysql/但它不起作用，尽管我认为我已经一步一步地遵循了它。不起作用的是在我的数据库中写入一些行。你能给一些提示吗？非常感谢您的宝贵时间。这是日志猫:

02-22 05:10:45.262: E/AndroidRuntime(1202): FATAL EXCEPTION: AsyncTask #2
02-22 05:10:45.262: E/AndroidRuntime(1202): Process: com.example.test, PID: 1202
02-22 05:10:45.262: E/AndroidRuntime(1202): java.lang.RuntimeException: An error occured while executing     doInBackground()
02-22 05:10:45.262: E/AndroidRuntime(1202):     at android.os.AsyncTask$3.done(AsyncTask.java:300)
02-22 05:10:45.262: E/AndroidRuntime(1202):     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
02-22 05:10:45.262: E/AndroidRuntime(1202):     at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
02-22 05:10:45.262: E/AndroidRuntime(1202):     at java.util.concurrent.FutureTask.run(FutureTask.java:242)
02-22 05:10:45.262: E/AndroidRuntime(1202):     at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
02-22 05:10:45.262: E/AndroidRuntime(1202):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
02-22 05:10:45.262: E/AndroidRuntime(1202):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
02-22 05:10:45.262: E/AndroidRuntime(1202):     at java.lang.Thread.run(Thread.java:841)
02-22 05:10:45.262: E/AndroidRuntime(1202): Caused by: java.lang.NullPointerException
02-22 05:10:45.262: E/AndroidRuntime(1202):     at com.example.test.MainActivity$CreateNewRow.doInBackground(MainActivity.java:134)
02-22 05:10:45.262: E/AndroidRuntime(1202):     at com.example.test.MainActivity$CreateNewRow.doInBackground(MainActivity.java:1)
02-22 05:10:45.262: E/AndroidRuntime(1202):     at android.os.AsyncTask$2.call(AsyncTask.java:288)
02-22 05:10:45.262: E/AndroidRuntime(1202):     at java.util.concurrent.FutureTask.run(FutureTask.java:237)
02-22 05:10:45.262: E/AndroidRuntime(1202):     ... 4 more

这是我的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($_POST['nume']) && isset($_POST['masa']) && isset($_POST['ip'])) {

$nume = $_POST['nume'];
$masa = $_POST['masa'];
$ip = $_POST['ip'];

// include db connect class
require_once __DIR__ . '/db_connect.php';

// connecting to db
$db = new DB_CONNECT();

// mysql inserting a new row
$result = mysql_query("INSERT INTO test2(null,nume, masa, ip) VALUES(null,'$nume', '$masa', '$ip')");

// 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);
}
?>

这是我的解析器:

package com.example.test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
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 jArr=null;
    static String json = "";

    // function get json from url
    // by making HTTP POST or GET method
    public static 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,"utf-8"));

                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 {
            jArr = new JSONObject(json);
        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        // return JSON String (Array)
        return jArr;

    }

}

这是我的主要 Activity :

package com.example.test;

import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.ArrayList;
import java.util.Enumeration;
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.os.AsyncTask;
import android.os.Bundle;
import android.text.format.Formatter;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
//import java.util.logging.Formatter;


public class MainActivity extends Activity {

    // Progress Dialog
    private ProgressDialog pDialog;

    JSONParser jsonParser = new JSONParser();
    EditText inputName;
    EditText inputDesc;

    // url to create new product
    private static String url_create_row = "http://localhost/android_connect/create_row.php";

    // JSON Node names
    private static final String TAG_SUCCESS = "success";

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

        // Edit Text
        inputName = (EditText) findViewById(R.id.inputName);
        inputDesc = (EditText) findViewById(R.id.inputDesc);
        inputDesc.setText(getLocalIpAddress().toString());

        // Create button
        Button btnCreateProduct = (Button) findViewById(R.id.btnAdaugare);

        // button click event
        btnCreateProduct.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                // creating new product in background thread
                new CreateNewRow().execute();
            }
        });

    }

    public String getLocalIpAddress() {
        try {
            for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
                NetworkInterface intf = en.nextElement();
                for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {
                    InetAddress inetAddress = enumIpAddr.nextElement();
                    if (!inetAddress.isLoopbackAddress()) {
                        String ip = Formatter.formatIpAddress(inetAddress.hashCode());
                        Log.i(TAG_SUCCESS, "****IP="+ip);
                        return ip;

                    }
                }
            }
        } catch (SocketException ex) {
            System.out.println("lala"+ex.toString());
        }
        return null;
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }
    /**
     * Background Async Task to Create new product
     * */
    class CreateNewRow extends AsyncTask<String, String, String> {

        /**
         * Before starting background thread Show Progress Dialog
         * */
       /* @Override
        protected void onPreExecute() {
            super.onPreExecute();

            pDialog.setMessage("Creating Row..");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
            Log.d(TAG_SUCCESS, "SUCCESSSSSSSSS!");
        }*/

        /**
         * Creating product
         * */
        protected String doInBackground(String... args) {

            String nume = inputName.getText().toString();
            String ip = inputDesc.getText().toString();
            String masa = "1";
            // Building Parameters
            List <NameValuePair> params = new ArrayList<NameValuePair>();

            params.add(new BasicNameValuePair("nume", nume));
            params.add(new BasicNameValuePair("masa", masa));
            params.add(new BasicNameValuePair("IP", ip));

            // getting JSON Object
            // Note that create product url accepts POST method
            JSONObject json = JSONParser.makeHttpRequest(url_create_row, "POST", params);

            // check log cat for response
            Log.d("Create Response", json.toString());

            // check for success tag
            try {
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // successfully created product
                    Toast.makeText(MainActivity.this, "s-a adaugat ceva in baza de date!", Toast.LENGTH_LONG).show();
                    // closing this screen
                    finish();
                } else {
                    // failed to create product
                    Log.d(TAG_SUCCESS, "Nu a mers nimic");
                }
            } 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();
        }*/


    }

}

我在 list 中添加了互联网权限和网络访问权限。任何建议都会有帮助并受到赞赏。

Answer 1

请注意 HTTP 参数区分大小写。

您正在发送

params.add(new BasicNameValuePair("IP", ip));

但你正在检查

isset($_POST['ip'])

应该是一样的:

params.add(new BasicNameValuePair("ip", ip));

您还错误地使用了异步任务:

protected JSONObject doInBackground(String... args) {

    String nume = inputName.getText().toString();
    String ip = inputDesc.getText().toString();
    String masa = "1";
    // Building Parameters
    List <NameValuePair> params = new ArrayList<NameValuePair>();

    params.add(new BasicNameValuePair("nume", nume));
    params.add(new BasicNameValuePair("masa", masa));
    params.add(new BasicNameValuePair("IP", ip));

    // getting JSON Object
    // Note that create product url accepts POST method
   JSONObject json = JSONParser.makeHttpRequest(url_create_row, "POST", params);

    // check log cat for response
    Log.d("Create Response", json.toString());


    return json;
}

protected void onPostExecute(JSONObject json) {
    if(json != null){
    try {
        int success = json.getInt(TAG_SUCCESS);
         if (success == 1) {
            // successfully created product
         Toast.makeText(MainActivity.this, "s-a adaugat ceva in baza de date!",
                                            Toast.LENGTH_LONG).show();
            // closing this screen
            finish();
        } else {
            // failed to create product
            Log.d(TAG_SUCCESS, "Nu a mers nimic");
        }
    } catch (JSONException e) {
        e.printStackTrace();
    }
   }
}

不允许您在 doInBackground 中更新 UI(例如 toast)，您必须将该代码移至 onPostExecute。