public class MainActivityFragment extends Fragment {

ArrayList<HashMap<String,String>> city_list;
LinearLayout progress;
public MainActivityFragment() {
}
public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    setHasOptionsMenu(true);
    ReadJson json = new ReadJson();
    json.execute();
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    final View view= inflater.inflate(R.layout.fragment_main, container, false);

    final EditText search= (EditText) view.findViewById(R.id.search_view);
    search.setOnEditorActionListener(new TextView.OnEditorActionListener() {
        @Override
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
            if (actionId == EditorInfo.IME_ACTION_SEARCH ||
                    actionId == EditorInfo.IME_ACTION_DONE ||
                    actionId == EditorInfo.IME_ACTION_GO ||
                    event.getAction() == KeyEvent.ACTION_DOWN &&
                            event.getKeyCode() == KeyEvent.KEYCODE_ENTER) {
                    boolean found = false;
                   String inserted = v.getText().toString();
                    for(int i=0;i<city_list.size();i++){
                        if(inserted.equalsIgnoreCase(city_list.get(i).get("name").toString())){
                            found=true;
                            TextView id = (TextView) view.findViewById(R.id.city_id);
                            id.setText(city_list.get(i).get("id").toString());
                            TextView lat = (TextView) view.findViewById(R.id.city_lat);
                            lat.setText(city_list.get(i).get("lat").toString());
                            TextView lon = (TextView) view.findViewById(R.id.city_long);
                            lon.setText(city_list.get(i).get("lon").toString());
                        }
                    }

                    if(!found) {
                        Toast.makeText(getContext(), "City not found", Toast.LENGTH_SHORT).show();
                    }
                    InputMethodManager inputManager = (InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE);
                    inputManager.hideSoftInputFromWindow(getActivity().getCurrentFocus().getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
                    return true; // consume.
            }
            return false; // pass on to other listeners.
        }
    });

    return view;
}

public String loadJsonFromAsset(){
    String json = null;
    try{
        InputStream is = getActivity().getAssets().open("city.list.json");
        int size = is.available();
        byte[] buffer = new byte[size];
        is.read(buffer);
        is.close();
        json = new String(buffer,"UTF-8");
    } catch (IOException e) {
        e.printStackTrace();
        return null;
    }
    return json;
}

public class ReadJson extends AsyncTask<Void,Void,Void>{

    protected void onPreExecute(){
        getActivity().setContentView(R.layout.progressbar_layout);
        progress = (LinearLayout) getActivity().findViewById(R.id.progressbar_view);
        progress.setVisibility(View.VISIBLE);
    }

    protected void onPostExecute(Void result){
        progress.setVisibility(View.GONE);

    }

    @Override
    protected Void doInBackground(Void... params) {
        try{
            JSONObject obj = new JSONObject(loadJsonFromAsset());
            JSONArray cities = obj.getJSONArray("cities");
            city_list= new ArrayList<>();
            HashMap<String,String> m_li;

            for(int i=0;i<cities.length();i++){
                JSONObject jo_inside = cities.getJSONObject(i);
                String name = jo_inside.getString("name");
                Long id = jo_inside.getLong("_id");
                Double lat = jo_inside.getJSONObject("coord").getDouble("lat");
                Double lon = jo_inside.getJSONObject("coord").getDouble("lon");
                String s_id = id.toString();
                String s_lat = lat.toString();
                String s_lon = lon.toString();
                m_li = new HashMap<String, String>();
                m_li.put("name", name);
                m_li.put("id", s_id);
                m_li.put("lat", s_lat);
                m_li.put("lon", s_lon);

                city_list.add(m_li);

            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }
}

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

<LinearLayout
    android:id="@+id/progressbar_view"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center_horizontal"
    android:orientation="vertical" >

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

        <ProgressBar
            style="?android:attr/progressBarStyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical|center_horizontal" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical|center_horizontal"
            android:text="Loading data..." />
    </LinearLayout>

    <View
        android:layout_width="fill_parent"
        android:layout_height="1dp"
        android:background="#C0C0C0" />
</LinearLayout>