（这是 Carl Dea 所著的“JavaFX 2.0 by example”一书中的代码——代码示例可在 Apress 上免费获得，所以我相信他们不介意我在这里使用它）
我有完美运行的示例代码
package javafx2introbyexample.chapter1.recipe1_11;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.HPos;
import javafx.geometry.Insets;
import javafx.geometry.VPos;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ListView;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.VBox;
import javafx.scene.paint.Color;
import javafx.stage.Stage;
/**
*
* @author cdea
*/
public class CreatingAndWorkingWithObservableLists extends Application {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
Application.launch(args);
}
@Override
public void start(Stage primaryStage) {
primaryStage.setTitle("Chapter 1-11 Creating and Working with ObservableLists");
Group root = new Group();
Scene scene = new Scene(root, 400, 250, Color.WHITE);
// create a grid pane
GridPane gridpane = new GridPane();
gridpane.setPadding(new Insets(5));
gridpane.setHgap(10);
gridpane.setVgap(10);
// candidates label
Label candidatesLbl = new Label("Candidates");
GridPane.setHalignment(candidatesLbl, HPos.CENTER);
gridpane.add(candidatesLbl, 0, 0);
Label heroesLbl = new Label("Heroes");
gridpane.add(heroesLbl, 2, 0);
GridPane.setHalignment(heroesLbl, HPos.CENTER);
// candidates
final ObservableList<String> candidates = FXCollections.observableArrayList("Superman",
"Spiderman",
"Wolverine",
"Police",
"Fire Rescue",
"Soldiers",
"Dad & Mom",
"Doctor",
"Politician",
"Pastor",
"Teacher");
final ListView<String> candidatesListView = new ListView<String>(candidates);
candidatesListView.setPrefWidth(150);
candidatesListView.setPrefHeight(150);
gridpane.add(candidatesListView, 0, 1);
// heros
final ObservableList<String> heroes = FXCollections.observableArrayList();
final ListView<String> heroListView = new ListView<String>(heroes);
heroListView.setPrefWidth(150);
heroListView.setPrefHeight(150);
gridpane.add(heroListView, 2, 1);
// select heroes
Button sendRightButton = new Button(">");
sendRightButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent event) {
String potential = candidatesListView.getSelectionModel().getSelectedItem();
if (potential != null) {
candidatesListView.getSelectionModel().clearSelection();
candidates.remove(potential);
heroes.add(potential);
}
}
});
// deselect heroes
Button sendLeftButton = new Button("<");
sendLeftButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent event) {
String notHero = heroListView.getSelectionModel().getSelectedItem();
if (notHero != null) {
heroListView.getSelectionModel().clearSelection();
heroes.remove(notHero);
candidates.add(notHero);
}
}
});
VBox vbox = new VBox(5);
vbox.getChildren().addAll(sendRightButton,sendLeftButton);
gridpane.add(vbox, 1, 1);
GridPane.setConstraints(vbox, 1, 1, 1, 2,HPos.CENTER, VPos.CENTER);
root.getChildren().add(gridpane);
primaryStage.setScene(scene);
primaryStage.show();
}
}
它是用于在两个列表视图之间来回移动人员的代码，一次一个。我想要做的是可以一键选择和移动几个人。
我要更改的相关摘录是：
final ListView<String> candidatesListView = new ListView<String>(candidates);
candidatesListView.setPrefWidth(150);
candidatesListView.setPrefHeight(150);
gridpane.add(candidatesListView, 0, 1);
// heros
final ObservableList<String> heroes = FXCollections.observableArrayList();
final ListView<String> heroListView = new ListView<String>(heroes);
...
// select heroes
Button sendRightButton = new Button(">");
sendRightButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent event) {
String potential = candidatesListView.getSelectionModel().getSelectedItem();
if (potential != null) {
candidatesListView.getSelectionModel().clearSelection();
candidates.remove(potential);
heroes.add(potential);
}
}
});
// deselect heroes
Button sendLeftButton = new Button("<");
sendLeftButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent event) {
String notHero = heroListView.getSelectionModel().getSelectedItem();
if (notHero != null) {
heroListView.getSelectionModel().clearSelection();
heroes.remove(notHero);
candidates.add(notHero);
}
}
});
我尝试过的改变：
首先，我添加以下导入：
import javafx.scene.control.SelectionMode;
然后我添加行
candidatesListView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
heroListView.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
在两个列表的各自声明下方。
最后，我将事件按钮的处理代码更改为
public void handle(ActionEvent event) {
ObservableList<String> potential = candidatesListView.getSelectionModel().getSelectedItems();
if (potential != null) {
System.out.println(potential);
candidates.removeAll(potential);
heroes.addAll(potential);
candidatesListView.getSelectionModel().clearSelection();
}
}
那就是 - 我将其更改为 getSelectedItem_s_，然后我 addAll 和 removeAll 而不是仅仅添加/删除一个人。当我尝试将几个人移过来时，这只会使 listView 留空。是什么赋予了？
附言。我还尝试通过迭代列表“潜在”来一次添加/删除几个人，但这也给出了错误的结果。