使用JSON从数据库接收数据在模拟器中工作

Question

我已经构建了一个应用程序，它从我的MySql数据库接收一些字符串。当我在模拟器中运行它时，它可以工作，但每当我尝试在我的设备（Galaxy Nexus）上运行它时，我只是得到一个强制关闭。模拟器是GB（2.2），我的设备是JB（4.2.2）。我还在我的清单上添加了INTERNET权限。

ListDBItems.java

public class VideoController extends SherlockListActivity implements OnClickListener{

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //getWindow().setFormat(PixelFormat.TRANSLUCENT);
        setContentView(R.layout.dblist);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setTitle("DB ITEMS");

        ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();


        JSONObject json = JSONfunctions.getJSONfromURL("http://strongpixel.com/java/getDB.php");

        try{

            JSONArray  shows = json.getJSONArray("items");

            for(int i=0;i<shows.length();i++){                      
                HashMap<String, String> map = new HashMap<String, String>();    
                JSONObject e = shows.getJSONObject(i);

                map.put("id",  String.valueOf(i));
                map.put("name", "" + e.getString("name"));
                map.put("season", "Season: " + e.getString("season"));
                map.put("path", "" +  e.getString("path"));
                mylist.add(map);            
            }       
        }catch(JSONException e)        {
             Log.e("log_tag", "Error parsing data "+e.toString());
        }

        ListAdapter adapter = new SimpleAdapter(this, mylist , R.layout.dbitems, 
                        new String[] { "name", "season" }, 
                        new int[] { R.id.item_title, R.id.item_subtitle });

        setListAdapter(adapter);

        final ListView lv = getListView();
        lv.setTextFilterEnabled(true);  
        lv.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {              
                @SuppressWarnings("unchecked")
                HashMap<String, String> o = (HashMap<String, String>) lv.getItemAtPosition(position);                   
                Toast.makeText(VideoController.this, "ID '" + o.get("id") + "' was clicked.", Toast.LENGTH_SHORT).show(); 

                Intent myIntent = new Intent(VideoController.this, MainActivity.class);
                myIntent.putExtra("name", o.get("name")); 
                myIntent.putExtra("season", o.get("season")); 
                myIntent.putExtra("path", o.get("path")); 
                startActivity(myIntent); 
            }
        });
}

我的清单

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.spxc.ssa.streaming"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/Holo.Theme.Light.DarkActionBar" >
        <activity
            android:name="com.spxc.ssa.streaming.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>
        <activity
            android:name="com.spxc.ssa.streaming.VideoController"
            android:label="@string/app_name"
            android:configChanges="orientation">
        </activity>
        <activity
            android:name="com.spxc.ssa.streaming.PlayVideo"
            android:label="@string/app_name" >
        </activity>
    </application>
    <uses-permission android:name="android.permission.INTERNET"/>
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
</manifest>

最后但不是最后一次，logcat（NULL异常）

03-09 13:22:15.975: E/AndroidRuntime(5141): FATAL EXCEPTION: main
03-09 13:22:15.975: E/AndroidRuntime(5141): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.spxc.ssa.streaming/com.spxc.ssa.streaming.VideoController}: java.lang.NullPointerException
03-09 13:22:15.975: E/AndroidRuntime(5141):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2304)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2354)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at android.app.ActivityThread.access$600(ActivityThread.java:150)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1244)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at android.os.Handler.dispatchMessage(Handler.java:99)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at android.os.Looper.loop(Looper.java:137)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at android.app.ActivityThread.main(ActivityThread.java:5191)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at java.lang.reflect.Method.invokeNative(Native Method)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at java.lang.reflect.Method.invoke(Method.java:511)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at dalvik.system.NativeStart.main(Native Method)
03-09 13:22:15.975: E/AndroidRuntime(5141): Caused by: java.lang.NullPointerException
03-09 13:22:15.975: E/AndroidRuntime(5141):     at com.spxc.ssa.streaming.VideoController.onCreate(VideoController.java:44)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at android.app.Activity.performCreate(Activity.java:5104)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
03-09 13:22:15.975: E/AndroidRuntime(5141):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2258)
03-09 13:22:15.975: E/AndroidRuntime(5141):     ... 11 more

由于

编辑：JSONfunctions.java

package com.spxc.ssa.streaming.task;

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

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
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.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.util.Log;

public class JSONfunctions {

    public static JSONObject getJSONfromURL(String url){
        InputStream is = null;
        String result = "";
        JSONObject jArray = null;

        //http post
        try{
                HttpClient httpclient = new DefaultHttpClient();
                HttpPost httppost = new HttpPost(url);
                HttpResponse response = httpclient.execute(httppost);
                HttpEntity entity = response.getEntity();
                is = entity.getContent();

        }catch(Exception e){
                Log.e("log_tag", "Error in http connection "+e.toString());
        }

      //convert response to string
        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();
                result=sb.toString();
        }catch(Exception e){
                Log.e("log_tag", "Error converting result "+e.toString());
        }

        try{

            jArray = new JSONObject(result);            
        }catch(JSONException e){
                Log.e("log_tag", "Error parsing data "+e.toString());
        }

        return jArray;
    }
}