如何在 Java FXML 应用程序中初始化 DatePicker？

Question

单击“添加约会”按钮时，会弹出新表单，但 DatePicker 为空（应该填充 LocalDate.now()），并且 Saturday/Sunday 日期中的 none 是禁用。尝试在 Initialize 和启动新场景的方法中调用设置方法。无论我将它放在一个或另一个或两个中，它都不起作用。请告知我做错了什么。谢谢。

图像显示 DatePicker 值空白且日历中没有禁用的日期。

package gci.controllers.dialogs;

import gci.App;
import gci.models.Appointment;
import gci.utilities.CustomerDAO;
import java.io.IOException;
import java.net.URL;
import java.sql.SQLException;
import java.time.*;
import java.util.*;
import java.util.logging.*;
import java.util.stream.*;
import javafx.collections.*;
import javafx.event.ActionEvent;
import javafx.fxml.*;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.*;
import javafx.util.*;

public class AddAppointmentController implements Initializable {

    @FXML private ChoiceBox<String> nameChoiceBox;
    @FXML private ChoiceBox<String> typeChoiceBox;
    @FXML private ChoiceBox<String> timeChoiceBox;
    @FXML private Label titleLabel;
    @FXML private Label copyrightLabel;
    @FXML private Button saveButton;
    @FXML private Button cancelButton;
    @FXML private DatePicker datePicker;

    private final CustomerDAO dao = new CustomerDAO();
    private Stage stage;
    private static final Region modal = new Region();

    @Override
    public void initialize(URL url, ResourceBundle rb) {
        initApptChoiceBoxes();
        setDatePicker();
        setCopyright();
        modal.setStyle("-fx-background-color: #00000099;");
    }

    private void initApptChoiceBoxes() {
        try {
            nameChoiceBox.setItems(dao.retrieveAll().stream().map(m -> m.getName())
                .collect(Collectors.toCollection(FXCollections::observableArrayList)));
        } catch (SQLException ex) {
            Logger.getLogger(AddAppointmentController.class.getName()).log(Level.SEVERE, null, ex);
        }

        typeChoiceBox.setItems(FXCollections.observableArrayList("In-Person", "Phone", "WebMeeting"));
    }

    public void loadAddModifyAppointmentScene(Stage stage, Appointment appt) throws IOException {
        Stage addAppointmentForm = new Stage();
        FXMLLoader loader = new FXMLLoader();
        loader.setLocation(App.class.getResource("views/dialogs/add_appointment.fxml"));
        Parent root = loader.load();
        Parent parent = stage.getScene().getRoot();
        StackPane stack = new StackPane(parent, modal);
        modal.setVisible(true);
        stage.setScene(new Scene(stack));
        addAppointmentForm.setScene(new Scene(root));
        addAppointmentForm.initModality(Modality.WINDOW_MODAL);
        addAppointmentForm.initOwner(stage);
        addAppointmentForm.initStyle(StageStyle.UNDECORATED);
        AddAppointmentController controller = loader.getController();
        controller.setStage(addAppointmentForm);
        controller.setAppointment(appt);
        controller.setDatePicker();
        addAppointmentForm.show();
        addAppointmentForm.centerOnScreen();
    }

    private void setStage(Stage stage) {
        this.stage = stage;
    }

    private void setAppointment(Appointment appt) {
    }

    @FXML
    private void handleCancelButton(ActionEvent event) {
        this.stage.close();
        modalOff();
    }

    @FXML
    private void handleSaveButton(ActionEvent event) {

    }

    private void setCopyright() {
        int year = LocalDate.now().getYear();
        copyrightLabel.setText("Copyright © " + year + " Global Consulting Institution");
    }

    public void modalOff() {
        modal.setVisible(false);
    }

    private void setDatePicker() {
        datePicker = new DatePicker(LocalDate.now());
        StringConverter<LocalDate> converter = datePicker.getConverter();
        datePicker.setConverter(new StringConverter<LocalDate>() {
            @Override
            public String toString(LocalDate object) {
                return converter.toString(object);
            }

            @Override
            public LocalDate fromString(String string) {
                LocalDate date = converter.fromString(string);
                if (date.getDayOfWeek() == DayOfWeek.SATURDAY
                    || date.getDayOfWeek() == DayOfWeek.SUNDAY) {
                    return datePicker.getValue();
                } else {
                    return date;
                }
            }
        });

        datePicker.setDayCellFactory(d -> new DateCell() {
            @Override
            public void updateItem(LocalDate date, boolean empty) {
                super.updateItem(date, empty);
                setDisable(empty || date.getDayOfWeek() == DayOfWeek.SATURDAY
                    || date.getDayOfWeek() == DayOfWeek.SUNDAY);
            }
        });

        datePicker.valueProperty().addListener((obs, ov, nv) -> {
            if (nv.getDayOfWeek() == DayOfWeek.SATURDAY || nv.getDayOfWeek() == DayOfWeek.SUNDAY) {
                Alert alert = new Alert(Alert.AlertType.WARNING);
                alert.setTitle("Select Appointment");
                alert.setHeaderText(null);
                alert.setContentText("Business Hours are Mon - Fri, 8am - 5pm");
                alert.showAndWait();
            }
        });
    }

}

Answer 1

您在 setDatePicker() 中创建的 DatePicker 实例永远不会添加到场景中。它会覆盖加载 fxml 时由 FXMLLoader 注入的 DatePicker 对象（除非您没有正确添加 fx:id）。在这个方法中完成的所有其他修改也在这个实例上完成。

您需要更换线路

datePicker = new DatePicker(LocalDate.now());

和

datePicker.setValue(LocalDate.now());

一般来说，您不应该为 @FXML 带注释的字段赋值。如果需要 "fix" a NullPointerException 或类似的东西，您只需解决症状而不是解决实际问题。此规则可能有例外，但您需要注意的是，您需要确保自己将节点添加到场景中。

如何在 Java FXML 应用程序中初始化 DatePicker？

How do I initialize the DatePicker in a Java FXML app?

java

javafx

datepicker

fxml