Why does ListActivity not display last item in ArrayAdapter?

Question

I am using the following code for my main activity:

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;
 }

The user should be able to input values in the dialog box and the Name would be displayed in the list of created Trips. However, there seems to be a bug when there is only one value in the List because that item is not displayed. I've spent hours on this and can't figure it out.

EDIT: This is my TripsData code

public class 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

It looks like the issue is with your TripsData class, post that, also try and log the length of the adapter and the data source after you delete an item. I am guessing that those two numbers are getting out of sync somewhere.

• DGB: have you tried logging the lengths of the adapter and the datasource at each occurrence to make sure they are in sync?