php - 如何解决 org.json.JSONException 中的错误？

Question

我正在创建一个可以通过将 ID 号放入 editText 来检索单词的应用程序。我不断收到此错误。如何解决这个问题呢？ org.json.JSONException: {"server_response": "Bird"} 没有值

这是我的主要 Activity.java

package com.example.keam.lastnato;

import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

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.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;

public class MainActivity extends Activity {

String id;
String word;
InputStream is=null;
String result=null;
String line=null;
String data ="";
TextView disp;
String url = "http://192.168.0.10/checkpls.php";

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

    final EditText e_id=(EditText) findViewById(R.id.editText1);
    Button select=(Button) findViewById(R.id.button1);
    disp = (TextView)findViewById(R.id.textView);
    select.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            id = e_id.getText().toString();
            select();
        }
    });
}

public void select()
{
    class readThis extends AsyncTask<String, Void, String> {
        protected String doInBackground(String... params){

ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

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

            try
            {
                HttpClient httpclient = new DefaultHttpClient();
                HttpPost httppost = new HttpPost(params[0]);
    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);
                }
                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);
                word = json_data.getString(result);
                Toast.makeText(getBaseContext(), "Name: " + word, 
                Toast.LENGTH_SHORT).show();

            }

            catch(JSONException e)
            {
                Log.e("Fail 3", e.toString());
                Log.e("log_tag", "Failed data was: " + result);
            }
            return word;
        }
    }

    readThis hello = new readThis();
    hello.execute(new String[] {url});
}
}

这是我的 activity_main.xml

<?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="com.example.keam.lastnato.MainActivity">

<EditText
    android:id="@+id/editText1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="39dp"
    android:padding="11dp"
    android:hint="Id"
    android:ems="10"
    android:inputType="number">

    <requestFocus />
</EditText>

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_below="@+id/editText1"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="24dp"
    android:onClick="parseJSON"
    android:padding="11dp"
    android:text="Select" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="New Text"
    android:id="@+id/textView"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true" />
 </RelativeLayout>

这是我的 PHP 文件“checkpls.php”

 <?php
$con = mysqli_connect("localhost", "root", "1234", "check") or die ("Error ".mysqli_error($con));
$id = $_POST['id'];
$sql = "SELECT * FROM tblcheckword where id like '$id';";
$result = mysqli_query($con, $sql) or die("Error in selecting ".mysqli_error($con));

$response = array();
if(mysqli_num_rows($result) > 0){
    while($row = mysqli_fetch_array($result))
    {
        array_push($response, array("id"=>$row[0],"word"=>$row[1],"meaning"=>$row[2]));
        $retrieve = $row[1];
    }
    echo json_encode(array("server_response" => $retrieve));
}else{
    echo "Retrieve failed";
}

mysqli_close($con);


?>

这是我在 WAMP phpmyadmin 中的 tblcheckword

数据库名称 = "检查"

这是我的 logcat 错误。

08-19 14:10:48.367 23305-23536/com.example.keam.lastnato E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
                                                                       Process: com.example.keam.lastnato, PID: 23305
                                                                       java.lang.RuntimeException: An error occured while executing doInBackground()
                                                                           at android.os.AsyncTask$3.done(AsyncTask.java:300)
                                                                           at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
                                                                           at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
                                                                           at java.util.concurrent.FutureTask.run(FutureTask.java:242)
                                                                           at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
                                                                           at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
                                                                           at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
                                                                           at java.lang.Thread.run(Thread.java:841)
                                                                        Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
                                                                           at android.os.Handler.<init>(Handler.java:200)
                                                                           at android.os.Handler.<init>(Handler.java:114)
                                                                           at android.widget.Toast$TN.<init>(Toast.java:372)
                                                                           at android.widget.Toast.<init>(Toast.java:105)
                                                                           at android.widget.Toast.makeText(Toast.java:264)
                                                                           at com.example.keam.lastnato.MainActivity$1readThis.doInBackground(MainActivity.java:120)
                                                                           at com.example.keam.lastnato.MainActivity$1readThis.doInBackground(MainActivity.java:61)
                                                                           at android.os.AsyncTask$2.call(AsyncTask.java:288)
                                                                           at java.util.concurrent.FutureTask.run(FutureTask.java:237)
                                                                           at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231) 
                                                                           at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
                                                                           at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
                                                                           at java.lang.Thread.run(Thread.java:841) 
   08-19 14:10:49.969 23305-23536/com.example.keam.lastnato I/Process: Sending signal. PID: 23305 SIG: 9

Answer 1

将 word = json_data.getString(result); 更改为 word = json_data.getString("server_response");

更新:

public void select(){
    readThis hello = new readThis();
    hello.execute(new String[] {url});
}

private class ReadThis extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... params) {
            ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();

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

            try
            {
                HttpClient httpclient = new DefaultHttpClient();
                HttpPost httppost = new HttpPost(params[0]);
    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);
                }
                is.close();
                result = sb.toString();
                Log.e("pass 2", "connection success ");
            }
            catch(Exception e)
            {
                Log.e("Fail 2", e.toString());
            }
            }
            return result ;
        }

        @Override
        protected void onPostExecute(String result) {
            try
        {

            JSONObject json_data = new JSONObject(result);
            word =  json_data.getString("server_response");
            Toast.makeText(getBaseContext(), "Name: " + word, 
            Toast.LENGTH_SHORT).show();

        }

        catch(JSONException e)
        {
            Log.e("Fail 3", e.toString());
            Log.e("log_tag", "Failed data was: " + result);
        }
        }

        @Override
        protected void onPreExecute() {}

        @Override
        protected void onProgressUpdate(Void... values) {}
    }