javafx - 使用多个值过滤 JFX TableView

Question

我目前正在尝试使用带有 predicate 的 FilteredList 来过滤我的 TableView 中的数据。我有 2 个 ComboBoxes 来过滤值。

我的表包含结果。每个 Result 都有一个 Student，那个 Student 有一个他所属的 Classroom。这些是我想要的值过滤它们。

当我仅使用 1 个 ComboBox 过滤数据时，我没有遇到任何问题。但是，我不知道如何同时基于两者进行过滤。我能想出的唯一真正的解决方案是在每个 ComboBox 的 changeListeners 中都有很多 if 语句，这似乎是一种不必要的复杂方式去做。

如果我使用以下代码，我的 TableView 中的值会显示多次。

  private void filterData(){
        ObservableList<Result> observableList = FXCollections.observableList(view.getResultTableView().getAllResultsList());
        FilteredList<Result> filteredData = new FilteredList<>(observableList, p -> true);

        view.getClassroomComboBox().getSelectionModel().selectedItemProperty().addListener((observable, oldValue, newValue) -> {

            filteredData.setPredicate(result -> {

                if (newValue.equals(view.getAllClassroomsChoice()) || newValue.equals(result.getStudent().getClassroom())) {
                    return true;
                }
                else
                    return false;
            });

            if(newValue.equals(view.getAllClassroomsChoice())){
                view.getStudentComboBox().setAllStudents();
            }
            else{
                view.getStudentComboBox().setStudentsByClassroom((Classroom) newValue);
            }
        });

        view.getStudentComboBox().getSelectionModel().selectedItemProperty().addListener((observable, oldValue, newValue) -> {
            filteredData.setPredicate(result -> {

                if (newValue.equals(view.getAllClassroomsChoice()) || newValue.equals(result.getStudent())) {
                    return true;
                }
                else
                    return false;
            });
        });


        SortedList<Result> sortedData = new SortedList<>(filteredData);

        sortedData.comparatorProperty().bind(view.getResultTableView().comparatorProperty());

        view.getResultTableView().setItems(sortedData);

    }

Answer 1

首先，不要每次都重新创建数据结构。只需更新 FilteredList 上的谓词。

您可以为每个组合框创建谓词并将每个谓词绑定(bind)到组合框中的值。然后您可以使用 Predicate.and(...) 组合谓词并将筛选列表的谓词属性绑定(bind)到结果。

这是一个类似的例子:

import java.util.Arrays;
import java.util.List;
import java.util.function.Function;
import java.util.function.Predicate;

import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.beans.value.ObservableValue;
import javafx.collections.FXCollections;
import javafx.collections.transformation.FilteredList;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.ComboBox;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.stage.Stage;

public class MultipleFilterTableExample extends Application {

    @Override
    public void start(Stage primaryStage) {
        TableView<Person> table = new TableView<>();
        table.getColumns().add(column("Name", Person::nameProperty));
        table.getColumns().add(column("Email", Person::emailProperty));
        table.getColumns().add(column("Gender", Person::genderProperty));

        ComboBox<Person.Gender> genderFilterCombo = new ComboBox<>();
        genderFilterCombo.getItems().addAll(Person.Gender.values());

        TextField nameFilterField = new TextField();

        ObjectProperty<Predicate<Person>> nameFilter = new SimpleObjectProperty<>();
        ObjectProperty<Predicate<Person>> genderFilter = new SimpleObjectProperty<>();

        nameFilter.bind(Bindings.createObjectBinding(() -> 
            person -> person.getName().toLowerCase().contains(nameFilterField.getText().toLowerCase()), 
            nameFilterField.textProperty()));


        genderFilter.bind(Bindings.createObjectBinding(() ->
            person -> genderFilterCombo.getValue() == null || genderFilterCombo.getValue() == person.getGender(), 
            genderFilterCombo.valueProperty()));

        FilteredList<Person> filteredItems = new FilteredList<>(FXCollections.observableList(createData()));
        table.setItems(filteredItems);

        filteredItems.predicateProperty().bind(Bindings.createObjectBinding(
                () -> nameFilter.get().and(genderFilter.get()), 
                nameFilter, genderFilter));

        Button clear = new Button("Clear Filters");
        clear.setOnAction(e -> {
            genderFilterCombo.setValue(null);
            nameFilterField.clear();
        });

        HBox filters = new HBox(5, nameFilterField, genderFilterCombo, clear);
        filters.setPadding(new Insets(5));
        BorderPane root = new BorderPane(table, filters, null, null, null);
        Scene scene = new Scene(root, 600, 600);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    private List<Person> createData() {
        return Arrays.asList(
                new Person("Jacob Smith", "jacob.smith@example.com", Person.Gender.MALE),
                new Person("Isabella Johnson", "isabella.johnson@example.com", Person.Gender.FEMALE),
                new Person("Ethan Williams", "ethan.williams@example.com", Person.Gender.MALE),
                new Person("Emma Jones", "emma.jones@example.com", Person.Gender.FEMALE),
                new Person("Michael Brown", "michael.brown@example.com", Person.Gender.MALE)
        );
    }

    private static <S,T> TableColumn<S,T> column(String title, Function<S, ObservableValue<T>> property) {
        TableColumn<S,T> col = new TableColumn<>(title);
        col.setCellValueFactory(cellData -> property.apply(cellData.getValue()));
        return col ;
    }

    public static class Person {

        public enum Gender {MALE, FEMALE }

        private final StringProperty name = new SimpleStringProperty();
        private final StringProperty email = new SimpleStringProperty() ;
        private final ObjectProperty<Gender> gender = new SimpleObjectProperty<>();

        public Person(String name, String email, Gender gender) {
            setName(name);
            setEmail(email);
            setGender(gender);
        }

        public final StringProperty emailProperty() {
            return this.email;
        }

        public final String getEmail() {
            return this.emailProperty().get();
        }

        public final void setEmail(final String email) {
            this.emailProperty().set(email);
        }

        public final ObjectProperty<Gender> genderProperty() {
            return this.gender;
        }

        public final Gender getGender() {
            return this.genderProperty().get();
        }

        public final void setGender(final Gender gender) {
            this.genderProperty().set(gender);
        }

        public final StringProperty nameProperty() {
            return this.name;
        }

        public final String getName() {
            return this.nameProperty().get();
        }

        public final void setName(final String name) {
            this.nameProperty().set(name);
        }

    }

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