I don't know but findBtView method cannot fint view and get null all the time.

File is in asset folder.
Debbuger shows that file iread ok and I can create Employee object from file.
Here is my layout with list:

    <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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context="com.miekinia.pawelziolkowski.rssreader1.EmployeesActivity">


    <ListView
        android:id="@+id/lvEmployees"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:listSelector="@drawable/big_card"></ListView>
</RelativeLayout>


Layout with item

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

    <android.support.v7.widget.CardView
        android:id="@+id/card_view"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        card_view:cardUseCompatPadding="true"
        card_view:cardElevation="3dp"
        card_view:cardCornerRadius="2dp">

        <RelativeLayout
            android:layout_width="fill_parent"
            android:layout_height="wrap_content">
            <TextView
                android:id="@+id/tvEmployeeNameSurname"
                android:fontFamily="sans-serif-light"
                android:textColor="#BF360C"
                android:layout_marginLeft="5dp"
                android:textSize="22dp"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content" />

            <TextView
                android:id="@+id/tvemployeePosition"
                android:layout_below="@id/tvEmployeeNameSurname"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="5dp"/>

            <TextView
                android:id="@+id/tvemployeePhone"
                android:layout_below="@id/tvemployeePosition"
                android:layout_width="fill_parent"
                android:layout_height="wrap_content"
                android:layout_marginLeft="5dp"/>
        </RelativeLayout>
    </android.support.v7.widget.CardView>


</LinearLayout>

activity


    package com.miekinia.pawelziolkowski.rssreader1;
        import android.app.Activity;
        import android.os.Bundle;
    import android.view.Menu;
    import android.view.MenuItem;
    import android.widget.ListView;

    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;

    import java.util.ArrayList;


    public class EmployeesActivity extends Activity {
        private ArrayList<Employee> employeesList=null;
        private JSONArray pracownicyJSONArrayFromJSON=null;

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

            this.pracownicyJSONArrayFromJSON = Utylities.loadJSONToJSONArray("pracownicy.json", this);

            employeesList= LoadListFromJSONArray();
            EmployeeAdapter ea = new EmployeeAdapter(employeesList);

            ListView employeesListView = (ListView) findViewById(R.id.lvEmployees);
            employeesListView.setAdapter(ea);
        }

        private ArrayList<Employee> LoadListFromJSONArray() {
            //int ArrayLength = this.pracownicyJSONArrayFromJSON.length();
            ArrayList<Employee> arrayList = new ArrayList<Employee>();

            for (int i = 0;i<this.pracownicyJSONArrayFromJSON.length(); i++) {
                try {
                    JSONObject jo = this.pracownicyJSONArrayFromJSON.getJSONObject(i);

                    Employee employee = new Employee();
                    employee.setName(jo.getString("imie"));
                    employee.setSurname(jo.getString("nazwisko"));
                    employee.setPosition(jo.getString("stanowisko"));
                    employee.setPhone(jo.getString("telefon"));

                    arrayList.add(employee);
                } catch (JSONException e) {
                    e.printStackTrace();
                    return arrayList;
                }
            }

            return  arrayList;
        }

        @Override
        public boolean onCreateOptionsMenu(Menu menu) {
            // Inflate the menu; this adds items to the action bar if it is present.
            getMenuInflater().inflate(R.menu.menu_employees, menu);
            return true;
        }

        @Override
        public boolean onOptionsItemSelected(MenuItem item) {
            // Handle action bar item clicks here. The action bar will
            // automatically handle clicks on the Home/Up button, so long
            // as you specify a parent activity in AndroidManifest.xml.
            int id = item.getItemId();

            //noinspection SimplifiableIfStatement
            if (id == R.id.action_settings) {
                return true;
            }

            return super.onOptionsItemSelected(item);
        }
    }

and adapter

    package com.miekinia.pawelziolkowski.rssreader1;

    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.TextView;

    import java.util.ArrayList;

    /**
     * Created by Ja on 2015-06-23.
     */
    public class EmployeeAdapter extends BaseAdapter
    {
        private ArrayList<Employee> employeesList;
        public EmployeeAdapter(ArrayList<Employee> employeesList) {
            this.employeesList = employeesList;
        }

        @Override
        public int getCount() {
            return this.employeesList.size();
        }

        @Override
        public Object getItem(int i) {
            return this.employeesList.get(i);
        }

        @Override
        public long getItemId(int i) {
            return i;
        }

        @Override
        public View getView(int i, View view, ViewGroup viewGroup) {

            if (view == null) {
                LayoutInflater li = LayoutInflater.from(viewGroup.getContext());
                view = li.inflate(R.layout.employee_listview_item,viewGroup, false);
            }

            TextView tvNameSurname = (TextView) viewGroup.findViewById(R.id.tvEmployeeNameSurname);
            tvNameSurname.setText(this.employeesList.get(i).getName() + " "+this.employeesList.get(i).getSurname());

            TextView tvPosition = (TextView) viewGroup.findViewById(R.id.tvemployeePosition);
            tvPosition.setText(this.employeesList.get(i).getPosition());

            TextView tvPhone = (TextView) viewGroup.findViewById(R.id.tvemployeePhone);
            tvPhone.setText(this.employeesList.get(i).getPhone());

            return view;
        }
    }