如何保存复选框的值与共享偏好？ [英] how can i save checkbox value with shared preferences?

问题描述

我不知道为什么我的代码不保存复选框检查值;如果我检查复选框，在我点击另一个选项卡并回到上一个选项卡，复选框未选择...我希望你在我的代码中找到错误！

I don't know why my code not save checkbox checked value; if I check checkbox and after I click on another tab and comeback to previous tab, checkbox is not selected...I hope that you find the error in my code!

IDE对我说： FATAL EXCEPTION：main java.lang.NullPointerException at line。 onCreateView（holder.chkBox.setChecked（true）;

为什么？

ADAPTER CLASS：

ADAPTER CLASS:

public abstract class PlanetAdapter extends ArrayAdapter<Planet> implements CompoundButton.OnCheckedChangeListener{

    private List<Planet> planetList;
    private Context context;
    ArrayList<Birra> objects;


    public PlanetAdapter(List<Planet> planetList, Context context) {
        super(context, R.layout.single_listview_item, planetList);
        this.planetList = planetList;
        this.context = context;
    }


    public class PlanetHolder {
        public TextView planetName;
        public TextView distView;
        public TextView valuta;
        public CheckBox chkBox;
        public EditText edit;
        public String quantità;


    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {


        View row = convertView;
        PlanetHolder holder = null;
        if (row == null) {
            LayoutInflater inflater = ((Activity) context).getLayoutInflater();
            row = inflater.inflate(R.layout.single_listview_item, parent, false);
            holder = new PlanetHolder();
            holder.planetName = (TextView) row.findViewById(R.id.name);
            holder.distView = (TextView) row.findViewById(R.id.dist);
            holder.valuta = (TextView) row.findViewById(R.id.valuta);
            holder.chkBox = (CheckBox) row.findViewById(R.id.chk_box);
            holder.edit = (EditText) row.findViewById(R.id.editText);
            holder.edit.setVisibility(View.GONE);
            holder.edit.setEnabled(false);
            row.setTag(holder);
        } else {
            holder = (PlanetHolder) row.getTag();
        }
        final Planet p = planetList.get(position);


        final PlanetHolder finalHolder = holder;

      /*SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
      boolean mCheckBoxValue = preferences .getBoolean("CheckBox_Value", false);

      if (mCheckBoxValue) {

          holder.chkBox.setChecked(true);
      } else {
          holder.chkBox.setChecked(false);
      }*/


        holder.chkBox.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (finalHolder.chkBox.isChecked()) {
                    finalHolder.edit.setVisibility(View.VISIBLE);
                    finalHolder.edit.setEnabled(true);
                    SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
                 /* SharedPreferences.Editor editor = preferences.edit();
                  editor.putBoolean("showActivity", finalHolder.chkBox.isChecked());
                  editor.commit();*/
                    // boolean value= true;
                    SharedPreferences.Editor mEditor = preferences.edit();
                    mEditor.putBoolean("CheckBox_Value", finalHolder.chkBox.isChecked());

                    mEditor.commit();

                    finalHolder.edit.addTextChangedListener(new TextWatcher() {
                        @Override
                        public void beforeTextChanged(CharSequence s, int start, int count, int after) {
                        }

                        @Override
                        public void onTextChanged(CharSequence s, int start, int before, int count) {
                        }

                        @Override
                        public void afterTextChanged(Editable s) {
                            p.setQuantità(finalHolder.edit.getText().toString().trim());
                            SharedPreferences preferences = getContext().getSharedPreferences("PROJECT_NAME", android.content.Context.MODE_PRIVATE);
                            SharedPreferences.Editor editor = preferences.edit();
                            editor.putString("KEY", finalHolder.edit.getText().toString().trim());

                            editor.commit();

                        }
                    });
                } else {
                    finalHolder.edit.setVisibility(View.GONE);
                    finalHolder.edit.setEnabled(false);
                    finalHolder.edit.setText(null);

                }

            }
        });
        holder.planetName.setText(p.getName());
        holder.distView.setText("" + p.getDistance());
        holder.valuta.setText("" + p.getValuta());
        holder.chkBox.setChecked(p.isSelected());
        holder.chkBox.setTag(p);
        holder.edit.setEnabled(false);

        return row;
    }


    ArrayList<Planet> getBox() {
        ArrayList<Planet> box = new ArrayList<Planet>();
        for (Planet p : planetList) {
            if (p.selected)
                box.add(p);
        }
        return box;
    }
}

FRAGMENT：

ListView lv;
ArrayList<Planet> planetList;
PlanetAdapter plAdapter;
BirraAdapter biAdapter;
PlanetAdapter.PlanetHolder holder;



 public class MyListFragment extends Fragment implements
        android.widget.CompoundButton.OnCheckedChangeListener {

    ListView lv;
    ArrayList<Planet> planetList;
    PlanetAdapter plAdapter;
    BirraAdapter biAdapter;
    PlanetAdapter.PlanetHolder holder;



    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment

        ViewGroup rootView = (ViewGroup) inflater.inflate(R.layout.fragment_list2, container, false);
        //@Override

        /* SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
            boolean mCheckBoxValue = preferences.getBoolean("CheckBox_Value", false);

            if (mCheckBoxValue) {
            holder.chkBox.setChecked(true);


            } else {
                holder.chkBox.setChecked(false);

        }*/


        Button mButton = (Button) rootView.findViewById(R.id.button);
        mButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
            showResult(v);


            }
        });
        //return inflater.inflate(R.layout.fragment_list2, container, false);
        return rootView;
    }


    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);


        lv = (ListView)getView().findViewById(R.id.listview);
        displayPlanetList();
    }


    private void displayPlanetList() {

        planetList = new ArrayList<Planet>();
        planetList.add(new Planet("Margherita", 6, "€"));
        planetList.add(new Planet("Diavola", 7,"€"));
        planetList.add(new Planet("Bufalina", 5,"€"));
        planetList.add(new Planet("Marinara", 5,"€"));
        planetList.add(new Planet("Viennese", 4, "€"));

        plAdapter = new PlanetAdapter(planetList, getContext()) {
            @Override
            public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

                int pos = lv.getPositionForView(buttonView);
                if (pos != ListView.INVALID_POSITION) {
                    Planet p = planetList.get(pos);
                    p.setSelected(isChecked);


            /*Toast.makeText(
                getActivity(),
                "Clicked on Pizza: " + p.getName() + ". State: is "
                        + isChecked, Toast.LENGTH_SHORT).show();*/
                }


            }
        };
        lv.setAdapter(plAdapter);
    }
    @Override
    public void onPause() {

        //get the instance variables
        SharedPreferences preferences = getContext().getSharedPreferences("MaterialTabs", android.content.Context.MODE_PRIVATE);
        boolean mCheckBoxValue = preferences.getBoolean("CheckBox_Value", false);

        if (mCheckBoxValue) {
            holder.chkBox.setChecked(true);


        } else {
            holder.chkBox.setChecked(false);



        }
        super.onPause();
    }




    public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

        /*int pos = lv.getPositionForView(buttonView);
        if (pos != ListView.INVALID_POSITION) {
            Planet p = planetList.get(pos);
            p.setSelected(isChecked);


            *//*Toast.makeText(
                getActivity(),
                "Clicked on Planet: " + p.getName() + ". State: is "
                        + isChecked, Toast.LENGTH_SHORT).show();*//*
        }*/

    }


    public void showResult(View v) {
        String  result2 = "Selected Product are :";
        int totalAmount2=0;

        String a="";
        for (Birra b : biAdapter.getBox()){

            if (b.selected){

                result2 += "\n" + b.name+" "+b.distance+"€"+"q.tà :"+b.getQuantità();
                int quantitaInt= Integer.parseInt(b.getQuantità());
                totalAmount2+=b.distance * quantitaInt;
                //a=String.valueOf(totalAmount);


            }
        }
    /*  for (Planet p : plAdapter.getBox()) {
            if (p.selected){

                result += "\n" + p.name+" "+p.distance+"€"+"q.tà :"+p.getQuantità();
                int quantitaInt= Integer.parseInt(p.getQuantità() );
                totalAmount+=p.distance * quantitaInt;
                //a=String.valueOf(totalAmount);


            }
        }*/
      //Toast.makeText(getActivity(), result + "\n" + "Total Amount:=" + totalAmount + "€", Toast.LENGTH_LONG).show();
        Toast.makeText(getActivity(), result2 + "\n" + "Total Amount:=" + totalAmount2 + "€", Toast.LENGTH_LONG).show();

        /*Bundle bun2 = new Bundle();
        bun2.putString("scelta", result);
        TwoFragment fgsearch2 = new TwoFragment();
        fgsearch2.setArguments(bun2);
        android.support.v4.app.FragmentTransaction transaction2 = getActivity().getSupportFragmentManager().beginTransaction();
        transaction2.replace(R.id.content_main, fgsearch2);
        transaction2.commit();


        Bundle bun = new Bundle();
        bun.putString("totale", a);
        TwoFragment fgsearch = new TwoFragment();
        fgsearch.setArguments(bun);
        android.support.v4.app.FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
        transaction.replace(R.id.content_main2, fgsearch);
        transaction.commit();
*/













    }




}

推荐答案

@Override

    protected void onCreate(Bundle savedInstanceState) {

        // TODO Auto-generated method stub

        super.onCreate(savedInstanceState);

        setContentView(R.layout.main);



        checkBox = (CheckBox) findViewById(R.id.checkBox1);                          
        SavedPreferences();

    }


    private void savePreferences(boolean value) {

        SharedPreferences sharedPreferences = PreferenceManager

                .getDefaultSharedPreferences(this);

        Editor editor = sharedPreferences.edit();

        editor.putBoolean(value);

        editor.commit();

    }





public class activity2 extends fragment{

       public onCreateView extends Fragment {
        SharedPreferences sharedPreferences = PreferenceManager

                .getDefaultSharedPreferences(this);

        boolean checkBoxValue = sharedPreferences.getBoolean("CheckBox_Value", false);    

        if (checkBoxValue) {

            checkBox.setChecked(true);

        } else {

            checkBox.setChecked(false);

        }


    }



    }

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