根据更改的日期（值）动态更新复选框列表

Question

我试图创建一个简单的清单与开始日期，以响应时间滑块指定的日期。

>

每个任务都有开始日期。

只有在任务开始日期已过的情况下才应呈现每个任务复选框。

public class ProjectChecklist extends Application {
  Group root = new Group();
  Scene scene = new Scene(root, 600, 300);
  VBox vbox = new VBox();
  HBox hbox = new HBox();
  ScrollPane scrollPane = new ScrollPane();


  taskList = getAllTasks(PROJECT_FILENAME);
  todayDate = LocalDate.now();
  sliderStartDate = taskList.get(0).getStartDate();
  LocalDate sliderEndDate = taskList.get(taskList.size() - 1).getEndDate();

  long days = ChronoUnit.DAYS.between(sliderStartDate, sliderEndDate);
  long daysFromToday = ChronoUnit.DAYS.between(sliderStartDate, todayDate);

  slider = new Slider(0, days, 1);
  slider.setValue(daysFromToday);
  sliderValue = new Label(LocalDate.now().toString());
  slider.setMajorTickUnit(1);
  slider.setShowTickLabels(true);

  scrollPane.setVbarPolicy(ScrollBarPolicy.AS_NEEDED);
  scrollPane.setHbarPolicy(ScrollBarPolicy.AS_NEEDED);

  slider.valueProperty().addListener(new ChangeListener<Number>() {
  public void changed(ObservableValue<? extends Number> observable, Number oldValue, Number newValue) {
    double daysValue = Math.round(newValue.doubleValue());
    LocalDate newDate = (sliderStartDate.plusDays((long) daysValue));
    slider.setValue(daysValue);
    sliderValue.setText(newDate.toString());
  }
  int taskNumber = 1;

  for (ChecklistTask task : taskList) {
    if (!task.getStartDate().isAfter(todayDate)) {
      CheckBox newCB = new CheckBox();
      newCB.setText("task " + taskNumber++ + ": " + task.getDescription());
      vbox.getChildren().add(newCB);
    }
  }
  vbox.getChildren().add(slider);
  vbox.getChildren().add(sliderValue);
  hbox.getChildren().add(vbox);
  hbox.setSpacing(40);
  hbox.setPadding(new Insets(10, 10, 10, 10));

  scrollPane.setContent(hbox);
  scrollPane.setPrefSize(600, 300);
  scrollPane.setFitToHeight(true);

  root.getChildren().add(scrollPane);

  primaryStage.setTitle("Bennington checklist");
  primaryStage.setScene(scene);
}

public static void main(String args[]) {
  launch(args);
  runApplication();
}

checklistTask.java

import java.time.LocalDate;
import java.util.UUID;

public class ChecklistTask{
    private UUID id;
    private String description;
    private LocalDate startDate;
    private LocalDate endDate;

    public ChecklistTask() {
        this.id = UUID.randomUUID();
    }

    public UUID getId() {
        return id;
    }

    public String getDescription() {
        return description;
    }

    public void setDescription(String description) {
        this.description = description;
    }

    public LocalDate getEndDate() {
        return endDate;
    }

    public void setEndDate(LocalDate endDate) {
        this.endDate = endDate;
    }

    public LocalDate getStartDate() {
        return startDate;
    }

    public void setStartDate(LocalDate startDate) {
        this.startDate = startDate;
    }

}

Answer 1

我建议使用由FilteredList支持的ListView，其中谓词将滑块值与ChequelistTask日期进行比较。更改滑块的值将自动更新用于筛选滑块的开始日期>选定日期的列表的谓词。过滤将负责相应地更新列表，而不必重新构建VBox内容。

下面是一个在发生变化时更新谓词的示例：JavaFX FilteredList，基于列表中项的属性进行过滤