Listview ist wieder leer nach dem Neustart der App Android

Question

Ich soll eine Notiz/Erinnerung Art der Anwendung machen. Mein Problem ist, dass, wenn ich die Anwendung beende, die Listview (die angeblich die hinzugefügten Notizen enthalten) leer ist. Ich werde hier alle meine Codes posten. Wie behalte ich die Notizen auch nach dem Beenden der App, ohne die Datenbank zu verwenden?

MainActivity.java 


public class MainActivity extends AppCompatActivity { 

    private NoteAdapter mNoteAdapter; 
    private boolean mSound; 
    private int mAnimOption; 
    private SharedPreferences mPrefs; 

    Animation mAnimFlash; 
    Animation mAnimFadeIn; 

    int mIDBeep = -1; 
    SoundPool nsp; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 


     if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) { 
      AudioAttributes audioAttributes = new AudioAttributes.Builder() 
        .setUsage(AudioAttributes.USAGE_MEDIA) 
        .setContentType(AudioAttributes.CONTENT_TYPE_SONIFICATION) 
        .build(); 

      nsp = new SoundPool.Builder().setMaxStreams(5).setAudioAttributes(audioAttributes).build(); 

     }else{ 
      // sp = new SoundPool(5, AudioAttributes.STREAM_MUSIC,0); 
     } 

     try{ 
      AssetManager assetManager = this.getAssets(); 
      AssetFileDescriptor descriptor; 

      //Load our fx 
      descriptor = assetManager.openFd("fx1.ogg"); 
      mIDBeep = nsp.load(descriptor,0); 


     } catch (IOException e) { 
      Log.e("error", "failed to load sound files"); 


     mNoteAdapter = new NoteAdapter(); 
     ListView listNote = (ListView)findViewById(R.id.listView); 
     listNote.setAdapter(mNoteAdapter); 
      listNote.setLongClickable(true); 


      listNote.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() { 
       @Override 
       public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) { 
        mNoteAdapter.deleteNote(position); 
        return true; 
       } 
      }); 


     listNote.setOnItemClickListener(new AdapterView.OnItemClickListener() { 
      @Override 
      public void onItemClick(AdapterView<?> parent, View view, int whichItem, long id) { 

       if (mSound){ 
        nsp.play(mIDBeep, 1,1,0,0,1); 
       } 

        Note tempNote = mNoteAdapter.getItem(whichItem); 

        DialogShowNote dialog = new DialogShowNote(); 
        dialog.sendNoteSelected(tempNote); 
        dialog.show(getFragmentManager(), ""); 







      } 
     }); 



    }} 

    public void createNewNote(Note n) { 
     mNoteAdapter.addNote(n); 
    } 


    public void addNote(View view) { 
     DialogNewNote dialog = new DialogNewNote(); 
     dialog.show(getFragmentManager(), ""); 

    } 



    public void viewSettings(View view){ 
     Intent intent = new Intent(this, SettingsActivity.class); 
     startActivity(intent); 
    } 


    public class NoteAdapter extends BaseAdapter{ 

     private JSONSerializer mSerializer; 
     List<Note> noteList = new ArrayList<Note>(); 

     public NoteAdapter(){ 
      mSerializer = new JSONSerializer("NotetoSelf.json",MainActivity.this.getApplicationContext()); 

      try{ 
       noteList= mSerializer.load(); 
      }catch (Exception e){ 
       noteList = new ArrayList<Note>(); 
       Log.e("Error loading notes: ","",e); 
      } 
     } 

     public void saveNote(){ 
      try{ 
       mSerializer.save(noteList); 
      }catch (Exception e){ 
       Log.e("Error Saving notes: ","",e); 
      } 
     } 
     public int getCount() { 
      return noteList.size(); 
     } 

     public Note getItem(int whichItem) { 
      return noteList.get(whichItem); 
     } 


     public long getItemId(int whichItem) { 
      return whichItem; 
     } 

     public View getView(int whichItem, View view, ViewGroup viewGroup){ 
      if(view == null){ 
       LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
       view = inflater.inflate(R.layout.list_item, viewGroup, false); 
      } 

      //Grab a referece to all our TextView and ImageView Widgets 
      TextView txtTitle = (TextView) view.findViewById(R.id.txtTitle); 
      TextView txtDescription = (TextView) view.findViewById(R.id.txtDescription); 

      ImageView ivImportant = (ImageView) view.findViewById(R.id.imageViewImportant); 
      ImageView ivToDo = (ImageView) view.findViewById(R.id.imageTodo); 
      ImageView ivIdea = (ImageView) view.findViewById(R.id.imageViewIdea); 


      Note tempNote = noteList.get(whichItem); 

      if(!tempNote.ismImportant() && mAnimOption != SettingsActivity.NONE){ 
       view.setAnimation(mAnimFlash); 

      } 
      else{ 
       view.setAnimation(mAnimFadeIn); 
      } 
      if(!tempNote.ismImportant()){ 
       ivImportant.setVisibility(View.GONE); 

      } 
      if(!tempNote.ismTodo()){ 
       ivToDo.setVisibility(View.GONE); 

      } 
      if(!tempNote.ismIdea()){ 
       ivIdea.setVisibility(View.GONE); 

      } 

      txtTitle.setText(tempNote.getmTitle()); 
      txtTitle.setText(tempNote.getmDescription()); 
      return view; 
     } 
     public void deleteNote(int n){ 
      noteList.remove(n); 
      notifyDataSetChanged(); 
     } 

     public void addNote(Note n){ 
      noteList.add(n); 
      notifyDataSetChanged(); 
     } 
    } 

    protected void onResume(){ 
     super.onResume(); 

     mPrefs = getSharedPreferences("Note to Self", MODE_PRIVATE); 
     mSound = mPrefs.getBoolean("sound", true); 
     mAnimOption = mPrefs.getInt("anim option",SettingsActivity.FAST); 

     mAnimFlash = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.flash); 
     mAnimFadeIn= AnimationUtils.loadAnimation(getApplicationContext(), R.anim.fade_in); 


     //set the rate of flash based on settings 
     if(mAnimOption == SettingsActivity.FAST) { 
      mAnimFlash.setDuration(100); 
      Log.i("anime = ", "" + mAnimOption); 
     }else if(mAnimOption == SettingsActivity.SLOW) 
     { 
      mAnimFlash.setDuration(1000); 
      Log.i("anime = ", "" + mAnimOption); 
      } 
     mNoteAdapter.notifyDataSetChanged();; 
     } 

    protected void onPause(){ 

    } 

    } 

Note.java

public class Note { 
    private String mTitle; 
    private String mDescription; 
    private boolean mIdea; 
    private boolean mTodo; 
    private boolean mImportant; 

    private static final String JSON_TITLE = "title"; 
    private static final String JSON_DESCRIPTION = "description"; 
    private static final String JSON_IDEA = "idea"; 
    private static final String JSON_TODO= "todo"; 
    private static final String JSON_IMPORTANT = "important"; 


    //constructor 

    public Note(JSONObject jo) throws JSONException{ 
     mTitle = jo.getString(JSON_TITLE); 
     mDescription = jo.getString(JSON_DESCRIPTION); 
     mIdea = jo.getBoolean(JSON_IDEA); 
     mTodo = jo.getBoolean(JSON_TODO); 
     mImportant = jo.getBoolean(JSON_IMPORTANT); 

    } 


    public Note(){ 

    } 

    public JSONObject convertToJSON() throws JSONException{ 
     JSONObject jo = new JSONObject(); 
     jo.put(JSON_TITLE,mTitle); 
     jo.put(JSON_DESCRIPTION,mDescription); 
     jo.put(JSON_IDEA,mIdea); 
     jo.put(JSON_TODO,mTodo); 

     return jo; 

    } 

    public String getmTitle() { 
     return mTitle; 
    } 

    public void setmTitle(String mTitle) { 
     this.mTitle = mTitle; 
    } 

    public String getmDescription() { 
     return mDescription; 
    } 

    public void setmDescription(String mDescription) { 
     this.mDescription = mDescription; 
    } 

    public boolean ismIdea() { 
     return mIdea; 
    } 

    public void setmIdea(boolean mIdea) { 
     this.mIdea = mIdea; 
    } 

    public boolean ismTodo() { 
     return mTodo; 
    } 

    public void setmTodo(boolean mTodo) { 
     this.mTodo = mTodo; 
    } 

    public boolean ismImportant() { 
     return mImportant; 
    } 

    public void setmImportant(boolean mImportant) { 
     this.mImportant = mImportant; 
    } 
} 

JSONserializer.java

public class JSONSerializer { 
private String mFilename; 
private Context mContext; 

public JSONSerializer(String fn, Context con){ 
    mFilename = fn; 
    mContext = con; 
} 

public void save(List<Note> notes)throws IOException, JSONException{ 
    //Make an array in JSON fomat 
    JSONArray jArray = new JSONArray(); 

    //And load it with the notes 
    for(Note n : notes) { 
     jArray.put(n.convertToJSON()); 

     //Now write it to the private disk space of our app 
     Writer writer = null; 
     try{ 
      OutputStream out = mContext.openFileOutput(mFilename,mContext.MODE_PRIVATE); 

      writer = new OutputStreamWriter(out); 
      writer.write(jArray.toString()); 

     }finally { 
      if(writer != null){ 
       writer.close(); 
      } 
     } 
    } 
} 

public ArrayList<Note> load() throws IOException,JSONException{ 
    ArrayList<Note> noteList = new ArrayList<Note>(); 
    BufferedReader reader = null; 
    try{ 
     InputStream in = mContext.openFileInput(mFilename); 
     reader = new BufferedReader(new InputStreamReader(in)); 
     StringBuilder jsonString = new StringBuilder(); 
     String line = null; 

     while ((line = reader.readLine()) != null) 
      jsonString.append(line); 

     JSONArray jArray = (JSONArray)new JSONTokener(jsonString.toString()).nextValue(); 
     for (int i = 0; i < jArray.length(); i++) 
      noteList.add(new Note(jArray.getJSONObject(i))); 

    }catch (FileNotFoundException e){ 
     //we will ignore this one, since it happens 
     //when we start fresh, You could add a log here. 
    }finally{ 
     if (reader != null) 
      reader.close(); 
    } 

    return noteList; 
} 
} 

DialogNewNote.java

public class DialogNewNote extends DialogFragment { 

@Override 
public Dialog onCreateDialog(Bundle savedInstanceState) { 
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity()); 
    LayoutInflater inflater = getActivity().getLayoutInflater(); 
    View dialogView = inflater.inflate(R.layout.dialog_new_note, null); 

    final EditText editTitle = (EditText) dialogView.findViewById(R.id.editTitle); 
    final EditText editDescription = (EditText) dialogView.findViewById(R.id.editDescription); 
    final CheckBox checkBoxIdea = (CheckBox) dialogView.findViewById(R.id.checkBoxIdea); 
    final CheckBox checkBoxToDo = (CheckBox) dialogView.findViewById(R.id.checkBoxToDo); 
    final CheckBox checkBoxImportant = (CheckBox) dialogView.findViewById(R.id.checkBoxImportant); 
    Button btnCancel = (Button) dialogView.findViewById(R.id.btnCancel); 
    Button btnOk = (Button) dialogView.findViewById(R.id.btnOk); 


    builder.setView(dialogView).setMessage("Add a new note"); 


    btnCancel.setOnClickListener(new View.OnClickListener(){ 
     public void onClick(View view){ 
      dismiss(); 
     } 
    }); 

    btnOk.setOnClickListener(new View.OnClickListener(){ 
     @Override 
     public void onClick(View v) { 
      Note newNote = new Note(); 


      newNote.setmTitle(editTitle.getText().toString()); 
      newNote.setmDescription(editDescription.getText().toString()); 
      newNote.setmIdea(checkBoxIdea.isChecked()); 
      newNote.setmTodo(checkBoxToDo.isChecked()); 
      newNote.setmImportant(checkBoxImportant.isChecked()); 



      MainActivity callingActivity = (MainActivity) getActivity(); 
      callingActivity.createNewNote(newNote); 
      dismiss(); 

     } 
    }); 

return builder.create(); 

} 


} 

DialogShowNote.java

01.235.

public class DialogShowNote extends DialogFragment { 
public Note mNote; 


@Override 
public Dialog onCreateDialog(Bundle savedInstanceState) { 
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity()); 

    LayoutInflater inflater = getActivity().getLayoutInflater(); 
    View dialogView = inflater.inflate(R.layout.dialog_show_note, null); 

    TextView txtTitle = (TextView)dialogView.findViewById(R.id.txtTitle); 
    TextView txtDescription = (TextView)dialogView.findViewById(R.id.txtDescription); 

    ImageView ivImportant = (ImageView)dialogView.findViewById(R.id.imageViewImportant); 
    ImageView ivtoDo = (ImageView)dialogView.findViewById(R.id.imageViewBlank); 
    ImageView ivIdea = (ImageView)dialogView.findViewById(R.id.imageViewIdea); 

    if (!mNote.ismImportant()) { 
     ivImportant.setVisibility(View.GONE); 
    } 

    if (!mNote.ismTodo()) { 
     ivtoDo.setVisibility(View.GONE); 
    } 


    if (!mNote.ismIdea()) { 
     ivIdea.setVisibility(View.GONE); 
    } 

    Button btnOK = (Button)dialogView.findViewById(R.id.btnOk); 
    builder.setView(dialogView).setMessage("Your Note"); 

    btnOK.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      dismiss(); 
     } 
    }); 

    return builder.create(); 

    } 

public void sendNoteSelected(Note noteSelected){ 
    mNote = noteSelected; 

    } 
} 

Answer 1

Verwenden Sie die freigegebenen prefrences Ihre Daten zu speichern und auch wieder verwenden, um Daten seiner einfachen retrive

Answer 2

Ich fand, wo ich schief gelaufen ist. Ich musste nur die saveNote() innerhalb der addNote hinzufügen und das war's.