无法从sharedpreference获取数据？

Question

这是我的疑问，我内部有一个活动，即一个片段需要从片段数据中填充活动中的listview。 但是，当我从活动列表视图数据中按“后退”按钮时，我的疑问是如何永久存储数据？我已经阅读了有关共享首选项的信息，在这里我们可以永久存储和检索数据，但是当我使用它时，我并不会永久存储列表视图值缺少作为Android的新值，到目前为止，我对此一直感到困惑：

这是我的片段：

package first.service.precision.servicefirst;

import android.app.Activity;
import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.EditText;

/**
 * Created by 4264 on 16-12-2015.
 */
public class NewCompetitors extends Fragment {
    CompetitorsData competitorsData;


    CompetitorsView competitorsView = new CompetitorsView();
EditText editText_name,editText_website,editText_strength,editText_weakness;
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.new_competitors_fragment, container, false);
        editText_name = (EditText) rootView.findViewById(R.id.competitors_name);
        editText_website = (EditText) rootView.findViewById(R.id.competitors_website);
        editText_strength = (EditText) rootView.findViewById(R.id.competitors_strength);
         editText_weakness = (EditText) rootView.findViewById(R.id.competitors_weakness);
        Button btn_save = (Button) rootView.findViewById(R.id.btn_save);

        btn_save.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                editTextcompetitor();
                sendData(competitorsView);
                getActivity().getFragmentManager().popBackStack();
            }
               });
            return rootView;
    }

public void editTextcompetitor(){
    competitorsView.setCompetitor_name(editText_name.getText().toString());
    competitorsView.setCompetitor_website(editText_website.getText().toString());
    competitorsView.setCompetitor_strength(editText_strength.getText().toString());
    competitorsView.setCompetitor_weakness(editText_weakness.getText().toString());

}

    public void sendData(CompetitorsView competitorsView){
  competitorsData.dataToCompetitorActivity(competitorsView);


    }

 @SuppressWarnings("deprecation")
    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
           competitorsData = (CompetitorsData) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString()+ "");
        }
    }
public interface CompetitorsData{
    void dataToCompetitorActivity(CompetitorsView competitorsView);
}
}

这是我填充列表视图的活动：

package first.service.precision.servicefirst;

import android.app.FragmentTransaction;
import android.content.Context;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;

public class Competitors extends Main2Activity implements NewCompetitors.CompetitorsData{
ListView lv;
    SharedPreferences sharedPreferences;
   List<CompetitorsView> competitorsViews;
    CompetitorsListAdapter competitorsListAdapter;
Context context;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_competitors);
        LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View contentView = inflater.inflate(R.layout.activity_competitors, null, false);
        mDrawerLayout.addView(contentView, 0);
        lv=(ListView)findViewById(R.id.list_competitors);
competitorsViews=new ArrayList<CompetitorsView>();
        competitorsListAdapter=new CompetitorsListAdapter(this,R.id.list_competitors,competitorsViews);
        lv.setAdapter(competitorsListAdapter);
        Button btn_competitors=(Button)findViewById(R.id.btn_new_competitors);
        SharedPreferences sharedPreferences= PreferenceManager.getDefaultSharedPreferences(this.getApplicationContext());
        SharedPreferences.Editor edit=sharedPreferences.edit();
        Gson gson=new Gson();
        String yog=sharedPreferences.getString("go","");
        Type type=new TypeToken<List<NewCompetitors>>(){}.getType();
        List<CompetitorsView>competitorsViews=gson.fromJson(yog,type);
        edit.commit();
        btn_competitors.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                NewCompetitors fragment = new NewCompetitors();
                FragmentTransaction ft = getFragmentManager().beginTransaction();
                ft.add(R.id.competitors_frame, fragment);
                ft.addToBackStack(null);
                ft.commit();
            }
        });
    }



    @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_competitors, menu);
        return true;
    }


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

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

        return super.onOptionsItemSelected(item);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Gson gson = new Gson();
        String jsonCurProduct = gson.toJson(competitorsViews);

        SharedPreferences sharedPref = getApplicationContext().getSharedPreferences("yog", Context.MODE_PRIVATE);
        SharedPreferences.Editor editor = sharedPref.edit();
        editor.putString("go", jsonCurProduct);
        editor.commit();
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        //ArrayList<CompetitorsView>cc=savedInstanceState.getParcelableArrayList("yog");
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
    }

    @Override
    public void dataToCompetitorActivity(CompetitorsView competitorsView)
    {
        competitorsViews.add(competitorsView);

        competitorsListAdapter.notifyDataSetChanged();



    }


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


    }
}

这是我的customlistadapter：

package first.service.precision.servicefirst;

import android.content.Context;
import android.graphics.Color;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

import java.util.List;

/**
 * Created by 4264 on 16-12-2015.
 */
public class CompetitorsListAdapter  extends ArrayAdapter<CompetitorsView> {

    private List<CompetitorsView> listData;
    private LayoutInflater layoutInflater;


    public CompetitorsListAdapter(Context context, int resource, List<CompetitorsView> listdata) {
        super(context, resource, listdata);
        this.listData = listdata;
        layoutInflater = LayoutInflater.from(context);
    }

    @Override
    public void add(CompetitorsView object) {
        super.add(object);
    }

    @Override
    public int getCount() {

        return listData.size();
    }

    @Override
    public CompetitorsView getItem(int position) {

        return listData.get(position);
    }


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

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;

        View mview = convertView;
        if (mview == null) {
            convertView = layoutInflater.inflate(R.layout.list_competitors, null);
            // TextView req = (TextView) convertView.findViewById(R.id.txt);
            //req.setText("Select Lead Information");
            holder = new ViewHolder();
            holder.competitors_name = (TextView) convertView.findViewById(R.id.company_grp);
            holder.competitors_website = (TextView) convertView.findViewById(R.id.company_name);
            holder.competitors_strength = (TextView) convertView.findViewById(R.id.addrsline);
            holder.competitors_weakness = (TextView) convertView.findViewById(R.id.stateid);

            //   add.lv.setVisibility(View.INVISIBLE);
            convertView.setTag(holder);

        } else {
            holder = (ViewHolder) convertView.getTag();
        }
        //    add.lv.setVisibility(View.VISIBLE);
        holder.competitors_name.setText("Competitors Name: " + listData.get(position).getCompetitor_name());
        holder.competitors_website.setText("Website: " + listData.get(position).getCompetitor_website());
        holder.competitors_strength.setText("Competitors Strength: " + listData.get(position).getCompetitor_strength());
        holder.competitors_weakness.setText("Competitors Weakness:" + listData.get(position).getCompetitor_weakness());

        convertView.setBackgroundColor(Color.parseColor("#ffffff"));
        return convertView;

    }

    static class ViewHolder {
        public TextView competitors_name;
        public TextView competitors_website;
        public TextView competitors_strength;
        public TextView competitors_weakness;
    }
}

它正在工作，但并没有存储价值！