Question

我想在JavaFX中从数据库中获取TableView，但是我有很多记录需要加载一小部分（例如50个位置），并且它会像我一样一点一点地得到剩余的记录。滚动滚轮。有小费吗？或者我在哪里可以找到一些好的例子？

Answer 1

作为一个例子，我将使用表示表中元素的Person类。

public class Person {

    private StringProperty firstName = new SimpleStringProperty(this, "firstName");

    private StringProperty lastName = new SimpleStringProperty(this, "lastName");

    public Person(String firstName, String lastName) {
        setFirsName(firstName);
        setLastName(lastName);
    }

    public void setFirsName(String firstName) {
        this.firstName.set(firstName);
    }

    public String getFirstName() {
        return firstName.get();
    }

    public void setLastName(String lastName) {
        this.lastName.set(lastName);
    }

    public String getLastName() {
        return lastName.get();
    }

    public StringProperty firstNameProperty() {
        return firstName;
    }

    public StringProperty lastNameProperty() {
        return lastName;
    }

}

这里是主类：

public class TableViewOnScroll extends Application {

    private ObservableList<Person> peopleToAdd;

    private int start = 0;
    private int step = 50;

    @Override
    public void start(Stage primaryStage) throws Exception {

        TableView<Person> tableView = new TableView<Person>();

        ObservableList<Person> displayedPeople = getInitialPeople();
        peopleToAdd = getPeopleToAdd();

        TableColumn<Person, String> firstNameCol = new TableColumn<Person, String>("First Name");
        firstNameCol.setCellValueFactory(new PropertyValueFactory("firstName"));
        TableColumn<Person,String> lastNameCol = new TableColumn<Person,String>("Last Name");
        lastNameCol.setCellValueFactory(new PropertyValueFactory("lastName"));

        tableView.getColumns().setAll(firstNameCol, lastNameCol);
        tableView.setItems(displayedPeople);

        primaryStage.setScene(new Scene(tableView, 600, 400));
        primaryStage.show();

        // Be sure to put the listener after the stage is shown or the application will throw a NullPointerException
        ScrollBar tableViewScrollBar = getTableViewScrollBar(tableView);
        tableViewScrollBar.valueProperty().addListener(new ChangeListener<Number>() {
            @Override
            public void changed(ObservableValue<? extends Number> observable, Number oldValue, Number newValue) {
                double position = newValue.doubleValue();
                ScrollBar scrollbar = getTableViewScrollBar(tableView);
                if(position == scrollbar.getMax()) {
                    if(step <= peopleToAdd.size()) {
                        displayedPeople.addAll(peopleToAdd.subList(start, step));
                        start = step;
                        step += 50;
                        tableView.scrollTo(start);
                    }
                }
            }
        });
    }

    public ObservableList<Person> getPeopleToAdd() {
        ObservableList<Person> people = FXCollections.observableArrayList();
        for(int i = 0; i < 500; i++) {
            people.add(new Person("Patty", "Johnson"));
        }

        return people;
    }

    public ObservableList<Person> getInitialPeople() {
        ObservableList<Person> people = FXCollections.observableArrayList();
        for(int i = 0; i < 50; i++) {
            people.add(new Person("John", "Smith"));
        }

        return people;
    }

    private ScrollBar getTableViewScrollBar(TableView<?> listView) {
        ScrollBar scrollbar = null;
        for (Node node : listView.lookupAll(".scroll-bar")) {
            if (node instanceof ScrollBar) {
                ScrollBar bar = (ScrollBar) node;
                if (bar.getOrientation().equals(Orientation.VERTICAL)) {
                    scrollbar = bar;
                }
            }
        }
        return scrollbar;
    }

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

使用getInitialPeople（）和getPeopleToAdd（）只是用一些随机数据填充列表。

使用滚动鼠标后显示数据

1 个答案: