爲什麼ListActivity不能顯示ArrayAdapter中的最後一項？

Question

我使用下面的代碼爲我的主要活動：

 
private TripsData datasource; 

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

     datasource = new TripsData(this); 
     datasource.open(); 

     List values = datasource.getAllTrips(); 

     ArrayAdapter adapter = new ArrayAdapter(this, 
       android.R.layout.simple_list_item_1, values); 
     setListAdapter(adapter); 
    } 

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

    // Will be called via the onClick attribute 
     // of the buttons in main.xml 
     public void onClick(View view) { 
     @SuppressWarnings("unchecked") 
     ArrayAdapter adapter = (ArrayAdapter) getListAdapter(); 
     Trip trip = null; 
     //Trip trip_temp; 
     switch (view.getId()) { 
     case R.id.add: 
      trip=newTrip(view); 
      //trip.setId(trip_temp.getId()); 
      //trip.setName(trip_temp.getName()); 
      adapter.add(trip); 
      break; 

     case R.id.delete: 
      if (getListAdapter().getCount() > 0) { 
       trip = (Trip) getListAdapter().getItem(0); 
       datasource.deleteTrip(trip); 
       adapter.remove(trip); 
      } 
      break; 
     } 
     adapter.notifyDataSetChanged(); 
     } 

     @Override 
     protected void onResume() { 
     datasource.open(); 
     super.onResume(); 
     } 

     @Override 
     protected void onPause() { 
     datasource.close(); 
     super.onPause(); 
     } 

     public Trip newTrip(View view){ 
      final Trip trip=new Trip(); 
      //create DialogBox 
      final Dialog dialog = new Dialog(this); 
      //modify features BEFORE setting content view 
      //dialog.requestWindowFeature(Window.FEATURE_NO_TITLE); 
      dialog.setContentView(R.layout.project_dialog); 
      //Create EditBoxes for Dialog 
      final EditText nameEdit=(EditText) dialog.findViewById(R.id.dialog_name_text); 
      final EditText descEdit=(EditText) dialog.findViewById(R.id.dialog_type_text); 
      //define button's text 
      View dialogButton=dialog.findViewById(R.id.dialog_button_create); 
      TextView text=(TextView) dialogButton; 
      text.setText("Create"); 
      //Button Creation 
      Button createButton = (Button) dialogButton; 
      // if button is clicked, close the custom dialog 
      createButton.setOnClickListener(new View.OnClickListener() { 
       @Override 
       public void onClick(View v) { 
        Trip trip_temp = datasource.createTrip(nameEdit.getText().toString()); 
        //String[] trips = new String[] { "Cool", "Very nice", "Hate it" }; 
        //int nextInt = new Random().nextInt(3); 
        // save the new comment to the database 
        trip.setId(trip_temp.getId()); 
        trip.setName(trip_temp.getName()); 
        //trip = datasource.createTrip(nameEdit.getText().toString()); 
        dialog.dismiss(); 
       } 
      }); 
      dialog.show(); 
      return trip; 
     } 

用戶應該能夠輸入值對話框，名稱將顯示在創建行程列表。但是，當列表中只有一個值時，似乎會出現一個錯誤，因爲該項目未顯示。我花了幾個小時，並無法弄清楚。

編輯： 這是我TripsData代碼

公共類TripsData {

private SQLiteDatabase database; 
private TripsDB dbHelper; 
private String[] allTrips = { TripsDB.TRIP_COLUMN_ID, 
     TripsDB.TRIP_COLUMN_TYPE}; 

public TripsData(Context context){ 
    dbHelper = new TripsDB(context); 
} 

public void open() throws SQLException{ 
    database = dbHelper.getWritableDatabase(); 
} 

public void close(){ 
    dbHelper.close(); 
} 

public Trip createTrip(String type){ 
    ContentValues values = new ContentValues(); 
    values.put(TripsDB.TRIP_COLUMN_TYPE, type); 
    long insertId = database.insert(TripsDB.TABLE_TRIPS, null, values); 
    Cursor cursor = database.query(TripsDB.TABLE_TRIPS, 
      allTrips, TripsDB.TRIP_COLUMN_ID + " = " + insertId, null, null, null, null); 
    cursor.moveToFirst(); 
    Trip newTrip = cursorToTrip(cursor); 
    cursor.close(); 
    return newTrip; 
} 

public void deleteTrip(Trip trip){ 
    long id = trip.getId(); 
    System.out.println("Project deleted with id: " + id); 
    database.delete(TripsDB.TABLE_TRIPS, TripsDB.TRIP_COLUMN_ID 
      + " = " + id, null); 
} 

public List<Trip> getAllTrips(){ 
    List<Trip> trips = new ArrayList<Trip>(); 

    Cursor cursor = database.query(TripsDB.TABLE_TRIPS, 
      allTrips, null, null, null, null, null); 

    cursor.moveToFirst(); 
    while(!cursor.isAfterLast()){ 
     Trip trip = cursorToTrip(cursor); 
     trips.add(trip); 
     cursor.moveToNext(); 
    } 
    cursor.close(); 
    return trips; 
} 

private Trip cursorToTrip(Cursor cursor){ 
    Trip trip = new Trip(); 
    trip.setId(cursor.getLong(0)); 
    trip.setName(cursor.getString(1)); 
    return trip; 
} 

Answer 1

它看起來像問題是與你的TripsData類的職位，也嘗試登錄的長度刪除項目後，適配器和數據源。我猜測這兩個數字在某個地方不同步。