Собственный адаптер и int android.view.View.getImportantForAccessibility()

Пишу собственный адаптер для отображения сообщений (текст,картинка,2 кнопки, текст). Столкнулся с такой проблемой: при отображении собственного ListView. Приложение вылетает с ошибкой:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.sttmmessenger, PID: 7402
    java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.View.getImportantForAccessibility()' on a null object reference
        at android.widget.AbsListView.obtainView(AbsListView.java:2508)
        at android.widget.ListView.measureHeightOfChildren(ListView.java:1301)
        at android.widget.ListView.onMeasure(ListView.java:1203)
        at android.view.View.measure(View.java:19147)
        at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:825)
        at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:511)
        at android.view.View.measure(View.java:19147)
        at android.support.constraint.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
        at android.support.constraint.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
        at android.view.View.measure(View.java:19147)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6136)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:223)
        at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:143)
        at android.view.View.measure(View.java:19147)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6136)
        at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:401)
        at android.view.View.measure(View.java:19147)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6136)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:223)
        at android.view.View.measure(View.java:19147)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6136)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1723)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:788)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:648)
        at android.view.View.measure(View.java:19147)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6136)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:223)
        at com.android.internal.policy.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2693)
        at android.view.View.measure(View.java:19147)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2484)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1443)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1697)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1324)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6712)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:894)
        at android.view.Choreographer.doCallbacks(Choreographer.java:696)
        at android.view.Choreographer.doFrame(Choreographer.java:631)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:880)
        at android.os.Handler.handleCallback(Handler.java:815)
        at android.os.Handler.dispatchMessage(Handler.java:104)
        at android.os.Looper.loop(Looper.java:207)
        at android.app.ActivityThread.main(ActivityThread.java:5728)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)

В чём причина? Где копать?

Код Адаптера OneMessageAdapter

package com.example.sttmmessenger;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.os.Build;
import android.support.annotation.RequiresApi;
import android.util.Base64;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ImageView;

import java.security.SecureRandom;
import android.widget.TextView;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class MessageAdapter extends ArrayAdapter<OneMessage> {
    ViewHolder viewHolder;
    MediaPlayer mediaPlayer;
    private static final String CHAR_LOWER = "abcdefghijklmnopqrstuvwxyz";
    private static final String CHAR_UPPER = CHAR_LOWER.toUpperCase();
    private static final String NUMBER = "0123456789";

    private static final String DATA_FOR_RANDOM_STRING = CHAR_LOWER + CHAR_UPPER + NUMBER;
    private static SecureRandom random = new SecureRandom();


    OneMessage product;
    private LayoutInflater inflater;
    private int layout;
    private ArrayList<OneMessage> productList;

    public MessageAdapter(Context context, int resource, List<OneMessage> objects) {

        super(context, resource, objects);
        this.inflater = inflater;
        this.layout = layout;
        this.productList = productList;
    }
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        String str=String.valueOf(layout);
        if(convertView==null&&inflater!=null&&parent!=null&&str!=null){
            convertView = inflater.inflate(R.layout.messagelistview, parent, false);
            viewHolder = new ViewHolder(convertView);
            convertView.setTag(viewHolder);
        }
        else{
            if(convertView!=null)viewHolder = (ViewHolder) convertView.getTag();
        }if(productList!=null&&productList.get(position)!=null) {
            product = productList.get(position);
        }

        if(viewHolder!=null) viewHolder.message_text.setText(product.getText());
        if(product!=null) if(product.getPicture()!=null) {
            byte[] decodedString = Base64.decode(product.getPicture(), Base64.DEFAULT);
            Bitmap decodedByte = BitmapFactory.decodeByteArray(decodedString, 0, decodedString.length);
            viewHolder.image.setImageBitmap(decodedByte);
        }

        if(viewHolder!=null)       viewHolder.hear_button.setOnClickListener(new View.OnClickListener() {
            @RequiresApi(api = Build.VERSION_CODES.KITKAT)
            @Override
            public void onClick(View v) {
                if(product!=null)
                    if(product.getVoice()!=null&&product.getVoice_text()!=null){
                        String path =generateRandomString(10)+".wav";
                        decoder(product.voice,path);
                        try {
                            StartPlayer(path);
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        if(viewHolder!=null) viewHolder.message_transcripted_audio.setText(product.getVoice_text());
                    }
            }
        });
        if(viewHolder!=null)  viewHolder.transcript_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

            }
        });

        return convertView;
    }


    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    public static void decoder(String base64Image, String pathFile) {
        try (FileOutputStream imageOutFile = new FileOutputStream(pathFile)) {
            byte[] imageByteArray = Base64.decode(base64Image,0);
            imageOutFile.write(imageByteArray);
        } catch (FileNotFoundException e) {
        } catch (IOException ioe) {
        }
    }
    public static String generateRandomString(int length) {
        if (length < 1) throw new IllegalArgumentException();

        StringBuilder sb = new StringBuilder(length);
        for (int i = 0; i < length; i++) {

            // 0-62 (exclusive), random returns 0-61
            if(DATA_FOR_RANDOM_STRING!=null) {
                int rndCharAt = random.nextInt(DATA_FOR_RANDOM_STRING.length());
                char rndChar = DATA_FOR_RANDOM_STRING.charAt(rndCharAt);


                sb.append(rndChar);
            }

        }
        if(sb!=null)
            return sb.toString();else return "asdsdasadsadadwasdadwasdawdasdwads";

    }

    public void StartPlayer(String  filePath) throws IOException {
        mediaPlayer = new MediaPlayer();
        if(mediaPlayer!=null) {
            mediaPlayer.setDataSource(filePath);
            mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
            Log.d("AUDIOSTATUS", "prepareAsync");
            mediaPlayer.setOnPreparedListener((MediaPlayer.OnPreparedListener) this);
            mediaPlayer.prepareAsync();
            mediaPlayer.start();
        }
    }
}
class ViewHolder {
     Button transcript_button, hear_button;
     TextView message_text, message_transcripted_audio;
     ImageView image;

    ViewHolder(View view){
        transcript_button = (Button) view.findViewById(R.id.transcript_audio);
        hear_button = (Button) view.findViewById(R.id.playaurdio);
        message_text = (TextView) view.findViewById(R.id.text_message);
        message_transcripted_audio = (TextView) view.findViewById(R.id.transcripted_text);
        image=(ImageView)view.findViewById(R.id.image_from_message);
    }
}

Код Класса OneMessage

package com.example.sttmmessenger;

public class OneMessage {
        public String picture;
        public String text;
        public int pos;
        public String voice_text;
        public String file;
        public String voice;
        public String filereso;

    public OneMessage(String picture, String text, int pos, String voice_text, String file, String voice, String filereso) {
        this.picture = picture;
        this.text = text;
        this.pos = pos;
        this.voice_text = voice_text;
        this.file = file;
        this.voice = voice;
        this.filereso = filereso;
    }

    public String getPicture() {
        return picture;
    }

    public void setPicture(String picture) {
        this.picture = picture;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    public int getPos() {
        return pos;
    }

    public void setPos(int pos) {
        this.pos = pos;
    }

    public String getVoice_text() {
        return voice_text;
    }

    public void setVoice_text(String voice_text) {
        this.voice_text = voice_text;
    }

    public String getFile() {
        return file;
    }

    public void setFile(String file) {
        this.file = file;
    }

    public String getVoice() {
        return voice;
    }

    public void setVoice(String voice) {
        this.voice = voice;
    }

    public String getFilereso() {
        return filereso;
    }

    public void setFilereso(String filereso) {
        this.filereso = filereso;
    }


}

Код рабочего класса peripiska.java

package com.example.sttmmessenger;

import android.content.Intent;
import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import com.google.gson.Gson;

import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.lang.reflect.Array;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;

public class Perepiska extends AppCompatActivity {
    ArrayList<OneMessage> messages_your = new ArrayList();
    ArrayList<OneMessage> messages_its = new ArrayList();



    class oneMessResponse {
        String status;
        public OneMessage[] Your;
        public OneMessage[] its;

        public String toStringerMessage() {
            Log.i("MESSAGE_RESPONSE","status:"+status +'\n'+ "yours: " + Your + '\n' + ",its:" + its);
            return "MessageResponse{"+"status:"+status +'\n'+ "yours: " + Your + '\n' + ",its:" + its + ')';
        }
    }

    String nick = null;
    String sobesednik = null;

    void parser( OneMessage[] its) {
        int lgth;
         lgth = its.length;
         String lengt = String.valueOf(lgth);
         Log.i("LENGTH_OF_ARRAY:", String.valueOf(lgth));
            OneMessage sobmsg[] = new OneMessage[lgth];
            Log.i("ЦИКЛ","ЩАС НАЧНЁтся");
            for (int i = 0; i <= lgth - 1; i++) {
                Log.i("ЦИКЛ","WORKS");
                if(i==its[i].pos){
                    sobmsg[i]=its[i];
                    messages_its.add(new OneMessage(sobmsg[i].getPicture(),sobmsg[i].getText(),sobmsg[i].getPos(),sobmsg[i].getVoice_text(),sobmsg[i].getFile(),sobmsg[i].getVoice(),sobmsg[i].getFilereso()));
                    Log.i("MESSAGE:","PICTURE:"+sobmsg[i].getPicture()+",TEXT:"+sobmsg[i].getText()+",POSITION:"+i);

                }else{sobmsg[i]=null;
                    messages_its.add(new OneMessage("","",i,"","","",""));
                    Log.i("MESSAGE:","ВСЁ КАВЫЧКИ"+i);
                    Log.d("His MESS",sobmsg[i].text);}
Log.i("FOR","WORKS");
            }
          //  ListView yourm = (ListView) findViewById(R.id.ListViewYou);
            ListView itsm = (ListView)findViewById(R.id.ListSobesednik);
          //  MessageAdapter yoursm = new MessageAdapter(this,R.layout.messagelistview,messages_your);
            MessageAdapter itsmad = new MessageAdapter(this,R.layout.messagelistview,messages_its);
        //    yourm.setAdapter(yoursm);
            itsm.setAdapter(itsmad);
            Log.i("SETED","SUCCESFULL");
        }



    class getMessages extends AsyncTask {
        Perepiska.oneMessResponse response;

        @Override
        protected void onPostExecute(Object o) {
            super.onPostExecute(o);
         if(response!=null)  if(response.its!=null)
            parser( response.its);else if(response.its==null)Log.d("NETU","EGO SOOBSH"); }

        @Override
        protected Object doInBackground(Object[] objects) {
            String set_server_url = "IP Адрес";//в приложении стоит нормальный
            URL url1 = null;
            try {
                url1 = new URL(set_server_url);
            } catch (MalformedURLException e) {
                e.printStackTrace();
            }
            if (url1 != null) {
                HttpURLConnection urlConnection = null;
                try {
                    urlConnection = (HttpURLConnection) url1.openConnection();
                } catch (IOException e) {
                    e.printStackTrace();
                }

                urlConnection.setDoOutput(true);
                OutputStream out = null;
                try {
                    out = urlConnection.getOutputStream();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                char c = '"';

                String action = "get_mess";

                String gm = "{\"action\":" + c + action + c + "," + "\"nickname\":" + c + nick + c + "," + "\"sobesednik\":" + c + sobesednik + c + "}";
                try {
                    if (out != null) {
                        out.write(gm.getBytes());
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
                Gson gson = new Gson();
                response = null;
                try {
                    response = gson.fromJson(new InputStreamReader(urlConnection.getInputStream()), Perepiska.oneMessResponse.class);
                    if (response != null) {
                        response.toStringerMessage();
                        urlConnection.disconnect();
                    }


                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (response != null) {
                    response.toStringerMessage();

                    return response;
                }
            }
            return 0;
        }

    }


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_perepiska);
        Bundle arguments = getIntent().getExtras();
        if (arguments != null) {
            nick = (String) arguments.get("username");
            sobesednik = (String) arguments.get("name_sobesednik");
getMessages gm = new getMessages();
gm.execute();
        }
    }
}

Разметка элемента собственного ListView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:id="@+id/message_list_adapter"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <TextView
        android:id="@+id/text_message"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_weight="5"
        android:gravity="center"
        android:text=""
        android:textAlignment="center"
        android:textStyle="bold" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <Button
            android:id="@+id/playaurdio"
            android:layout_width="57dp"
            android:layout_height="match_parent"
            android:text="PLY" />

        <Button
            android:id="@+id/transcript_audio"
            android:layout_width="wrap_content"
            android:layout_height="40dp"
            android:text="TRS" />
    </LinearLayout>

    <TextView
        android:id="@+id/transcripted_text"
        android:layout_width="match_parent"
        android:layout_height="81dp" />

    <ImageView
        android:id="@+id/image_from_message"
        android:layout_width="match_parent"
        android:layout_height="128dp"
        android:layout_weight="25" />

</LinearLayout>

Разметка perepiska_activity

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".Perepiska">
    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical" >

        <ListView
            android:id="@+id/ListSobesednik"
            android:layout_width="202dp"
            android:layout_height="match_parent" />

        <ListView
            android:id="@+id/ListViewYou"
            android:layout_width="203dp"
            android:layout_height="match_parent"
            android:layout_alignParentTop="true"
            android:layout_alignParentEnd="true"
            android:layout_alignParentRight="true"
            android:layout_marginTop="0dp"
            android:layout_marginEnd="0dp"
            android:layout_marginRight="0dp" />


        <LinearLayout
            android:id="@+id/layout_bottom_bar"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:background="#00BCD4"
            android:gravity="right"
            android:orientation="horizontal"
            android:padding="5dip">

            <EditText
                android:id="@+id/message"
                android:layout_width="200dp"
                android:layout_height="50dp"
                android:layout_alignTop="@+id/layout_bottom_bar" />
            <Button
                android:id="@+id/file"
                android:text="Ф"
                android:layout_width="50dp"
                android:layout_height="50dp" />
            <Button
                android:id="@+id/image"
                android:text="И"
                android:layout_width="50dp"
                android:layout_height="50dp" />

            <Button
                android:id="@+id/send"
                android:layout_width="50dp"
                android:layout_height="50dp"
                android:background="#D36964"
                android:text="ОТПР"
                android:textColor="#FFFFFF" />

        </LinearLayout>


    </RelativeLayout>
</android.support.constraint.ConstraintLayout>