Question

我想向JavaFX菜单添加选项列表。显示菜单时，应该修改选项的顺序（我将使用模糊匹配，但是该方法与我的问题无关）。我可以用分别包含CustomMenuItem和TextField的{{1}}来模仿这种行为：

ListView

但是，在菜单结构中包含import javafx.application.Application; import javafx.application.Platform; import javafx.beans.property.SimpleStringProperty; import javafx.beans.property.StringProperty; import javafx.collections.FXCollections; import javafx.collections.ObservableList; import javafx.scene.Scene; import javafx.scene.control.CustomMenuItem; import javafx.scene.control.ListView; import javafx.scene.control.Menu; import javafx.scene.control.MenuButton; import javafx.scene.control.TextField; import javafx.scene.input.MouseEvent; import javafx.stage.Stage; import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; public class MWE extends Application { @Override public void start(Stage primaryStage) { final Menu menu = new Menu("MENU"); final List<String> options = Arrays.asList( "AbC", "dfjksdljf", "skdlfj", "stackoverflow"); final StringProperty currentSelection = new SimpleStringProperty(null); final TextField fuzzySearchField = new TextField(null); final CustomMenuItem fuzzySearchItem = new CustomMenuItem(fuzzySearchField, false); // TODO unfortunately we seem to have to grab focus like this! fuzzySearchField.addEventFilter(MouseEvent.MOUSE_MOVED, e->{fuzzySearchField.requestFocus(); fuzzySearchField.selectEnd();}); final ObservableList<String> currentMatches = FXCollections.observableArrayList(); // just some dummy matching here fuzzySearchField.textProperty().addListener((obs, oldv, newv) -> currentMatches.setAll(options.stream().filter(s -> s.toLowerCase().contains(newv)).collect(Collectors.toList()))); final ListView<String> lv = new ListView<>(currentMatches); lv.addEventFilter(MouseEvent.MOUSE_MOVED, e -> lv.requestFocus()); final CustomMenuItem lvItem = new CustomMenuItem(lv, false); menu.getItems().setAll(fuzzySearchItem, lvItem); fuzzySearchField.textProperty().addListener((obs, oldv, newv) -> currentSelection.setValue(currentMatches.size() > 0 ? currentMatches.get(0) : null)); fuzzySearchField.setText(""); menu.setOnShown(e -> fuzzySearchField.requestFocus()); final MenuButton button = new MenuButton("menu"); button.getItems().setAll(menu); Platform.runLater(() -> { final Scene scene = new Scene(button); primaryStage.setScene(scene); primaryStage.show(); }); } }感到很奇怪。这就是为什么我尝试使用ListView而不是MenuItem的原因：

ListView

在该示例中，即使我看到import javafx.application.Application; import javafx.application.Platform; import javafx.beans.property.SimpleStringProperty; import javafx.beans.property.StringProperty; import javafx.collections.FXCollections; import javafx.collections.ListChangeListener; import javafx.collections.ObservableList; import javafx.scene.Scene; import javafx.scene.control.CustomMenuItem; import javafx.scene.control.ListView; import javafx.scene.control.Menu; import javafx.scene.control.MenuButton; import javafx.scene.control.MenuItem; import javafx.scene.control.TextField; import javafx.scene.input.MouseEvent; import javafx.stage.Stage; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; public class MWE2 extends Application { @Override public void start(Stage primaryStage) { final Menu menu = new Menu("MENU"); final List<String> options = Arrays.asList( "AbC", "dfjksdljf", "skdlfj", "stackoverflow"); final StringProperty currentSelection = new SimpleStringProperty(null); final TextField fuzzySearchField = new TextField(null); final CustomMenuItem fuzzySearchItem = new CustomMenuItem(fuzzySearchField, false); // TODO unfortunately we seem to have to grab focus like this! fuzzySearchField.addEventFilter(MouseEvent.MOUSE_MOVED, e->{fuzzySearchField.requestFocus(); fuzzySearchField.selectEnd();}); final ObservableList<String> currentMatches = FXCollections.observableArrayList(); // just some dummy matching here fuzzySearchField.textProperty().addListener((obs, oldv, newv) -> currentMatches.setAll(options.stream().filter(s -> s.toLowerCase().contains(newv)).collect(Collectors.toList()))); currentMatches.addListener((ListChangeListener<String>)change -> { List<MenuItem> items = new ArrayList<>(); items.add(fuzzySearchItem); currentMatches.stream().map(MenuItem::new).forEach(items::add); System.out.println("Updating menu items!"); menu.getItems().setAll(items); }); fuzzySearchField.textProperty().addListener((obs, oldv, newv) -> currentSelection.setValue(currentMatches.size() > 0 ? currentMatches.get(0) : null)); fuzzySearchField.setText(""); menu.setOnShown(e -> fuzzySearchField.requestFocus()); final MenuButton button = new MenuButton("menu"); button.getItems().setAll(menu); Platform.runLater(() -> { final Scene scene = new Scene(button); primaryStage.setScene(scene); primaryStage.show(); }); } }打印到控制台，菜单也不会在显示时更新，因此"Updating menu items!"的项目正在更新。但是，屏幕上的菜单不会更改。

有没有一种方法要求重新绘制菜单？

相关问题：

JavaFX: Update menu sub-items everytime menu shown解决方案似乎不正确，Menu似乎没有方法menu
Adding dynamic entries to Menu in JavaFX在显示菜单时不会更新菜单（如果我理解正确的话）

Answer 1

我按照建议@Enigo和@Jesse_mw使用了自定义节点。我决定使用仅包含ListView的{{1}}，而不是VBox，因为我只需要基本功能，并且不希望有其他令人困惑的处理程序或突出显示。还请注意，@kleopatra指出，不幸的是，dynamic updates of items works out of the box for ContextMenu (and a potential bug in Menu)并不是我的用例的适当选择。

这是我的最低工作示例代码：

Label

Answer 2

要正确地动态更新JavaFX中的列表，可以像在代码中那样将Binding与可观察列表一起使用。以下代码的唯一问题是，由于Menu类的功能，它将无法按预期运行，每次更新列表时，菜单都会隐藏。我认为您应该像评论中讨论的那样对列表视图进行样式设置，并再次使用以下绑定，因为它适用于使用我相信的所有可观察列表的视图。

import javafx.application.Application;
import javafx.application.Platform;
import javafx.beans.binding.Bindings;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.collections.FXCollections;
import javafx.collections.ListChangeListener;
import javafx.collections.ObservableList;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

import java.lang.management.PlatformManagedObject;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

public class MWE2 extends Application {
public static void main(String[] args) {
    launch(args);
}

@Override
public void start(Stage primaryStage) {
    final Menu menu = new Menu("MENU");
    final MenuButton button = new MenuButton("menu");
    final List<String> options = Arrays.asList(
            "AbC",
            "dfjksdljf",
            "skdlfj",
            "stackoverflow");

    final StringProperty currentSelection = new SimpleStringProperty(null);

    final TextField fuzzySearchField = new TextField(null);
    final CustomMenuItem fuzzySearchItem = new CustomMenuItem(fuzzySearchField, false);
    // TODO unfortunately we seem to have to grab focus like this!
    fuzzySearchField.addEventFilter(MouseEvent.MOUSE_MOVED, e -> {
        fuzzySearchField.requestFocus();
        fuzzySearchField.selectEnd();
    });
    final ObservableList<String> currentMatches = FXCollections.observableArrayList();
    // just some dummy matching here
    fuzzySearchField.textProperty().addListener((obs, oldv, newv) -> {

            currentMatches.setAll(options.stream().filter(s -> s.toLowerCase().contains(newv)).collect(Collectors.toList()));

    });
   //changed from ArrayList to ObservableArray
    ObservableList<MenuItem> items =  FXCollections.observableArrayList(); 
    currentMatches.addListener((ListChangeListener<String>) change -> {
        items.clear();//Clearing items to in-case of duplicates and NULL duplicates.
        items.add(fuzzySearchItem);

        currentMatches.stream().map(MenuItem::new).forEach(items::add);

        System.out.println("Updating menu items!");
        menu.getItems().setAll(items);


    });
    // Binding to Observable items.
    Bindings.bindContent(menu.getItems(), items); 
    fuzzySearchField.textProperty().addListener((obs, oldv, newv) -> currentSelection.setValue(currentMatches.size() > 0 ? currentMatches.get(0) : null));
    fuzzySearchField.setText("");


    button.getItems().setAll(menu);


    final Scene scene = new Scene(button);

    primaryStage.setScene(scene);
    primaryStage.show();

}

}

JavaFX：显示时动态更新菜单

2 个答案: