CommitEdit function gets executed on creation of t

问题:

I have a custom editable table cell for my table view. Now, the issue I have is that the commitEdit() function gets executed when the table is created. The issue is that it slows down the program as I'm updating items in my database and every single item gets updated.

public class ChoiceBoxCell extends TableCell<Student, Classroom> {

    ChoiceBox<Classroom> classroomChoiceBox;

    public ChoiceBoxCell(ObservableList<Classroom> classroomObservableList) {
        classroomChoiceBox = new ChoiceBox<>();
        classroomChoiceBox.setItems(classroomObservableList);

        classroomChoiceBox.getSelectionModel().selectedItemProperty().addListener((obs, oldValue, newValue) -> {
            if (newValue != null) {
                processEdit(newValue);
            }
        });
    }
    private void processEdit(Classroom value) {
        commitEdit(value);
        classroomChoiceBox.setValue(value);
        setGraphic(classroomChoiceBox);
    }

    @Override
    public void cancelEdit() {
        super.cancelEdit();
        setGraphic(classroomChoiceBox);
    }

    @Override
    public void commitEdit(Classroom value) { // gets executed on start up
        super.commitEdit(value);
        Student student = (Student) getTableRow().getItem();
        student.setClassroom(value);
        new StudentDao().updateStudent(student); // students get updated for no reason
        classroomChoiceBox.setValue(value);
        setGraphic(classroomChoiceBox);
    }

    @Override
    public void startEdit() {
        super.startEdit();
        Classroom value = getItem();
        if (value != null) {
            classroomChoiceBox.setValue(value);
            setGraphic(classroomChoiceBox);
        }
    }

    @Override
    protected void updateItem(Classroom item, boolean empty) {
        super.updateItem(item, empty);
        if (item == null || empty) {
            setGraphic(null);
        } else {
            classroomChoiceBox.setValue(item);
            setGraphic(classroomChoiceBox);
        }
    }
}

EDIT: Solution - thanks to @James_D

classroomChoiceBox.getSelectionModel().selectedItemProperty().addListener((obs, oldValue, newValue) -> {
        if (newValue != null && newValue != getItem()) {
            processEdit(newValue);
        }
    });

回答1:

Solution - thanks to James_D

classroomChoiceBox.getSelectionModel().selectedItemProperty().addListener((obs, oldValue, newValue) -> {
        if (newValue != null && newValue != getItem()) {
            processEdit(newValue);
        }
    });