java - AndroidnotifyDataSetChanged导致解析idx 1 Illegal State Exception

Question

在我的主要 Activity (LocalFeed)中，我有一个连接到 AsyncTask 的 ListView ，该任务以 Json 格式从数据库获取数据，然后将其发送到 BaseAdapter。我的问题是 notifyDataSetChanged() 对我没有任何作用(经过进一步研究，我得到了下面包含的 logcat 输出)，我在这里阅读了很多帖子，例如 Android notifyDataSetChanged not working并实现了他们的想法，但没有任何效果。我最初在设置适配器时获取数据，但是当我有新数据进入时，它保持不变，除非我再次调用 setAdapter，这是不好的做法。首先这是我的 Activity ..

public class LocalFeed extends Activity
{

 String localstreams;
EditText POST;
SharedPreferences myaccount,mya;

 String PathUrl;
 float tlatmin,tlatmax,tlonmin,tlonmax,latitudes,longitudes;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.local_feed);


  // Inputs that are used for the database
    PathUrl = getResources().getString(R.string.PathUrl);
    // URL for data api
    localstreams = PathUrl + "/api/streams";
    tlatmin = myaccount.getFloat("thirtylatmin", 0.0f);
    tlatmax = myaccount.getFloat("thirtylatmax", 0.0f);
    tlonmin = myaccount.getFloat("thirtylonmin", 0.0f);
    tlonmax = myaccount.getFloat("thirtylonmax", 0.0f);
    latitudes = myaccount.getFloat("latitudes", 0.0f);
    longitudes = myaccount.getFloat("longitudes", 0.0f);


    // This is the AsyncTask that will get the Json Data from the database
final ListView lv = (ListView) findViewById(R.id.localfeed);
    new Streams_Async(localstreams, tlatmin, tlatmax, tlonmin, tlonmax, LocalFeed.this, myaccount, 1,lv).execute();

    // I would like to setAdapter here but Json data only comes after onPostexecute of AsyncTask

}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater mif=getMenuInflater();
    mif.inflate(R.menu.menu_local_feed, menu);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();


    if (id == R.id.Logout) {

        SharedPreferences settings = getSharedPreferences("userInfo", MODE_PRIVATE);
        settings.edit().clear().commit();
      startActivity(new Intent(LocalFeed.this,Login.class));

        return true;
    }

    return super.onOptionsItemSelected(item);
}
}

我将 Listview 传递给 AsyncTask() 因为数据来自那里，所以在 onPostExecute() 方法之前我无法调用适配器。这是我的 AsyncTask()

public class Streams_Async extends AsyncTask<String,String,String> {
        HttpURLConnection conn;
        URL url;
        String result="";
        DataOutputStream wr;
       String Stream_URL;
        Activity m;
       Integer page;
    float tlatmin,tlatmax,tlonmin,tlonmax;
    SharedPreferences myaccount;


    public Streams_Async(String Stream_URL,float tlatmin,float tlatmax,float tlonmin,float tlonmax,Activity m,SharedPreferences myaccount,Integer page)
    {
        this.Stream_URL=Stream_URL;
        this.tlatmin=tlatmin;
        this.tlatmax=tlatmax;
        this.tlonmin=tlonmin;
        this.tlonmax=tlonmax;
        this.m=m;
        this.myaccount=myaccount;
        this.page=page;
    }

        @Override
        protected void onPreExecute() {
            super.onPreExecute();

        }

        @Override
        protected String doInBackground(String... params) {

// All This does it just get the data from the database
            BufferedReader reader=null;
            try{
                url = new URL(Stream_URL);
                conn = (HttpURLConnection) url.openConnection();
                conn.setDoOutput(true);
                conn.setRequestMethod("POST");
                conn.connect();

                conn.setReadTimeout(10000);
                conn.setConnectTimeout(15000);


                String cert="thirtylatmin="+myaccount.getFloat("thirtylatmin", 0)+"&thirtylatmax="+myaccount.getFloat("thirtylatmax", 0)+"&thirtylonmin="+myaccount.getFloat("thirtylonmin", 0)+"&thirtylonmax="+myaccount.getFloat("thirtylonmax", 0)+
                        "&page="+page+"&pid="+myaccount.getInt("id", 0);


                wr = new DataOutputStream(conn.getOutputStream());
                wr.writeBytes(cert);
                wr.flush();
                wr.close();

                reader =  new BufferedReader(new InputStreamReader(conn.getInputStream()));
                StringBuilder sBuilder = new StringBuilder();

                String line = "";
                while ((line = reader.readLine()) != null) {
                    sBuilder.append(line + "\n");
                }


                result = sBuilder.toString();
                reader.close();
                conn.disconnect();
                return result;



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

            return result;

        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
     // All the data needed for listview is in result variable
            try {

                JSONObject jsonn = new JSONObject(result);

                JSONArray jArray = jsonn.getJSONArray("localstreams");
                JSONObject jobject = null;
                JSONArray sss = new JSONArray();
                for (int i = 0; i < jArray.length(); i++) {
                    jobject = jArray.getJSONObject(i);
                    jobject.getString("post");
                    jobject.getString("fullname");
                    jobject.getInt("id");
                    jobject.getInt("myid");
                    jobject.getInt("reputation");
                    jobject.getString("city");
                    jobject.getString("last_reply");
                    jobject.getString("state");
                    sss.put(jobject);
                }

                jsonn.put("localstreams", sss);

   System.err.println("nnn: " + result);
       if (lv.getAdapter() == null)
        {
      ListView mm= (ListView) m.findViewById(R.id.localfeed);
            LocalFeed_CustomView DMF = new LocalFeed_CustomView(jsonn, m);
           mm.setAdapter(DMF);

    }
        else
        {
            // This right here does not work
            LocalFeed_CustomView DMF = new LocalFeed_CustomView(jsonn, m);
            DMF.notifyDataSetChanged();

        }

            }
            catch (Exception e) {
          System.err.println("pp"+e.getMessage());
            }

        }
    }

正如您所看到的，我的问题是在 onPostExecute 内的 else 语句中，它不起作用； **DMF.notifyDataSetChanged();**导致解析错误，我找不到如何克服该错误。

public class LocalFeed_CustomView extends BaseAdapter {

    JSONObject names;
    Context ctx;
   //,ra;
    String result="";
    private LayoutInflater mLayoutInflater = null;
    public  LocalFeed_CustomView(){}


    public LocalFeed_CustomView(JSONObject arr,Context c) {
        ctx = c;
        names = arr;
        mLayoutInflater = (LayoutInflater)ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        notifyDataSetChanged();

    }

    public void updateList(){
    notifyDataSetChanged();
}


    @Override
    public int getCount() {
        try {
            JSONArray jaLocalstreams = names.getJSONArray("localstreams");
            return jaLocalstreams.length();
        } catch (Exception e) {
            Toast.makeText(ctx,"Error: Please try again",Toast.LENGTH_LONG).show();
            return names.length();
        }


    }




    @Override
    public Object getItem(int position) {

        return position;
    }

    @Override
    public long getItemId(int position) {

        return position;
    }

    @Override
    public View getView(int position,View convertView, ViewGroup parent) {
        View row=convertView;
        MyViewHolder holder=null;
        try {

            if(row==null) {
             LayoutInflater li= (LayoutInflater) ctx.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                row = li.inflate(R.layout.customadapter, parent, false);

                holder=new MyViewHolder(row);
                row.setTag(holder);
            }
else
            {

                holder=(MyViewHolder)row.getTag();

            }
        updateList();

            // This populates Listview

            JSONArray jaLocalstreams = names.getJSONArray("localstreams");
            System.err.println("ssd:" + names);
            final JSONObject jsonObject = jaLocalstreams.getJSONObject(position);
            int a=  jsonObject.getInt("myid");

            holder.post.setText(jsonObject.getString("post"));
            holder.fullname.setText(jsonObject.getString("fullname"));
            holder.city.setText(jsonObject.getString("city")+ ", ");
            holder.state.setText(jsonObject.getString("state"));
            holder.comments.setText(jsonObject.getInt("comments")+ " Comments ");
            holder.last_reply.setText(jsonObject.getString("last_reply"));
            holder.reputation.setText(jsonObject.getString("reputation"));
            jsonObject.getInt("profile_id");
            jsonObject.getInt("id");

            SharedPreferences myaccount = ctx.getSharedPreferences("userInfo", MODE_PRIVATE);
            int my_id = myaccount.getInt("id", 0);

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


    }

     class MyViewHolder{
        TextView post,fullname,city,state,last_reply,comments,reputation;
         ImageButton reputation_add;

         MyViewHolder(View v)
         {
          post= (TextView)v.findViewById(R.id.post);
             fullname= (TextView)v.findViewById(R.id.fullname);
             city= (TextView)v.findViewById(R.id.city);
             state= (TextView)v.findViewById(R.id.state);
         last_reply= (TextView)v.findViewById(R.id.last_reply);
        comments = (TextView)v.findViewById(R.id.id);
         reputation= (TextView)v.findViewById(R.id.reputation);
           reputation_add= (ImageButton)v.findViewById(R.id.reputation_add);
         }



    }

}

下面是问题区域

 else
    {
        // This right here does not work
        LocalFeed_CustomView DMF = new LocalFeed_CustomView(jsonn, m);
        DMF.notifyDataSetChanged();

    }

它转到catch语句，它的原因是空，这是它的logcat..我的else代码中的什么可能导致这个错误

java.lang.IllegalStateException: problem parsing idx 1
            at com.android.internal.net.NetworkStatsFactory.readNetworkStatsDetail(NetworkStatsFactory.java:300)
            at com.android.server.NetworkManagementService.getNetworkStatsUidDetail(NetworkManagementService.java:1282)
            at com.android.server.net.NetworkStatsService.performPollLocked(NetworkStatsService.java:831)
            at com.android.server.net.NetworkStatsService.updateIfacesLocked(NetworkStatsService.java:743)
            at com.android.server.net.NetworkStatsService.updateIfaces(NetworkStatsService.java:721)
            at com.android.server.net.NetworkStatsService.access$000(NetworkStatsService.java:128)
            at com.android.server.net.NetworkStatsService$1.onReceive(NetworkStatsService.java:612)
            at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:728)
            at android.os.Handler.handleCallback(Handler.java:605)
            at android.os.Handler.dispatchMessage(Handler.java:92)
            at android.os.Looper.loop(Looper.java:137)
            at android.os.HandlerThread.run(HandlerThread.java:60)
     Caused by: java.io.FileNotFoundException: /proc/net/xt_qtaguid/stats: open failed: ENOENT (No such file or directory)
            at libcore.io.IoBridge.open(IoBridge.java:406)
            at java.io.FileInputStream.<init>(FileInputStream.java:78)
            at com.android.internal.net.NetworkStatsFactory.readNetworkStatsDetail(NetworkStatsFactory.java:269)
            at com.android.server.NetworkManagementService.getNetworkStatsUidDetail(NetworkManagementService.java:1282)
            at com.android.server.net.NetworkStatsService.performPollLocked(NetworkStatsService.java:831)
            at com.android.server.net.NetworkStatsService.updateIfacesLocked(NetworkStatsService.java:743)
            at com.android.server.net.NetworkStatsService.updateIfaces(NetworkStatsService.java:721)
            at com.android.server.net.NetworkStatsService.access$000(NetworkStatsService.java:128)
            at com.android.server.net.NetworkStatsService$1.onReceive(NetworkStatsService.java:612)
            at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:728)
            at android.os.Handler.handleCallback(Handler.java:605)
            at android.os.Handler.dispatchMessage(Handler.java:92)
            at android.os.Looper.loop(Looper.java:137)
            at android.os.HandlerThread.run(HandlerThread.java:60)
     Caused by: libcore.io.ErrnoException: open failed: ENOENT (No such file or directory)
            at libcore.io.Posix.open(Native Method)
            at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110)
            at libcore.io.IoBridge.open(IoBridge.java:390)
            at java.io.FileInputStream.<init>(FileInputStream.java:78)
            at com.android.internal.net.NetworkStatsFactory.readNetworkStatsDetail(NetworkStatsFactory.java:269)
            at com.android.server.NetworkManagementService.getNetworkStatsUidDetail(NetworkManagementService.java:1282)
            at com.android.server.net.NetworkStatsService.performPollLocked(NetworkStatsService.java:831)
            at com.android.server.net.NetworkStatsService.updateIfacesLocked(NetworkStatsService.java:743)
            at com.android.server.net.NetworkStatsService.updateIfaces(NetworkStatsService.java:721)
            at com.android.server.net.NetworkStatsService.access$000(NetworkStatsService.java:128)
            at com.android.server.net.NetworkStatsService$1.onReceive(NetworkStatsService.java:612)
            at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:728)
            at android.os.Handler.handleCallback(Handler.java:605)
            at android.os.Handler.dispatchMessage(Handler.java:92)
            at android.os.Looper.loop(Looper.java:137)
            at android.os.HandlerThread.run(HandlerThread.java:60)
09-30 03:47:45.001        36-67/? E/SurfaceTexture﹕ [com.exoler/com.exoler.Login] drainQueueLocked: SurfaceTexture has been abandoned!
09-30 03:47:45.261      158-188/com.android.inputmethod.latin E/ActivityThread﹕ Failed to find provider info for com.android.inputmethod.latin.dictionarypack
09-30 03:47:45.271      158-188/com.android.inputmethod.latin E/BinaryDictionaryGetter﹕ Could not find a dictionary pack

Answer 1

如果您的列表已经有一个适配器，也许您不需要重新创建一个，而是从列表中获取该适配器，为其设置新数据(此处考虑同步，因为另一个线程可能会尝试访问某些适配器)数据就在您更改它时)然后调用notifyDataSetChanged():

else {
    LocalFeed_CustomView DMF = (LocalFeed_CustomView) lv.getAdapter();
    synchronized (namesLock) {
        DMF.names = ...
    }
    DMF.notifyDataSetChanged();
}

相反，您创建一个新的、未分配的适配器，然后只需对其调用notifyDataSetChanged()。但它尚未添加到任何列表中，这可能会导致问题。无论如何，就您的情况而言，显然您想引用已经存在的适配器并更新已显示在屏幕上的列表。