结合 ObservableMap 绑定

Question

我有一个使用 ObservableMap<String, Member> 填充的组合。我想要的是，如果在组合中选择了一个项目（键），以便能够获得相应的对象（值）。这是我目前所拥有的

import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.logging.Level;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.ObservableMap;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
import org.controlsfx.control.textfield.TextFields;

public class ComboWithHashMap extends Application{
    private ComboBox autocompleteCombo = new ComboBox();
    private ObservableMap<String, Member> list;

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

    @Override
    public void start(Stage primaryStage) throws Exception {
        primaryStage.setTitle("Combo Sample");
        primaryStage.setWidth(450);
        primaryStage.setHeight(550);

        list = FXCollections.observableMap(getActiveMember());
        autocompleteCombo.getItems().setAll(list.keySet());
        //TextFields.bindAutoCompletion(autocompleteCombo.getEditor(), autocompleteCombo.getItems());
        Scene scene = new Scene(new BorderPane(autocompleteCombo), 880, 600);
        primaryStage.setScene(scene);
        primaryStage.show();
    }


    public HashMap<String, Member> getActiveMember(){
        HashMap<String, Member> map = new HashMap<String, Member>();
        Member member1 = new Member(1, "123", "John Doe");
        Member member2 = new Member(2, "234", "Sally Doe");
        Member member3 = new Member(3, "345", "Billy Doe");
        Member member4 = new Member(4, "567", "Mac Doe");
        Member member5 = new Member(5, "789", "Win Doe");

        map.put( member1.getMilkNo(), member1);
        map.put( member2.getMilkNo(), member2);
        map.put( member3.getMilkNo(), member3);

        return map;
    }

    public class Member {
        private int id;
        private String milkNo;
        private String fullName;

        public Member(int id, String milkNo, String fullName) {
            this.id = id;
            this.milkNo = milkNo;
            this.fullName = fullName;
        }

        public int getId() {
            return id;
        }

        public void setId(int id) {
            this.id = id;
        }


        public String getMilkNo() {
            return milkNo;
        }

        public void setMilkNo(String milkNo) {
            this.milkNo = milkNo;
        }

        @Override
        public String toString() {
            return fullName;
        }

    }

}

问题是目前我无法在选中某个键时获取到对应的对象（值）

Answer 1

获取组合框中字符串对应的对象值value property listener。代码如图所示

autocompleteCombo.valueProperty().addListener(new ChangeListener() {

    @Override
    public void changed(ObservableValue observable, Object oldValue, Object newValue) {
        Member member = (Member) list.get(newValue);
        System.out.println(member.getId());
        System.out.println(member.getMilkNo());
        System.out.println(member.getFullName());
    }
});

Answer 2

valueAt method of Bindings 在给定映射和键的 ObservableMap 中创建绑定：

ObjectBinding<Member> value = Bindings.valueAt(list, autocompleteCombo.valueProperty());

请注意，虽然如果 ObservableMap 更改此绑定将更新，但您的 ComboBox 的项目将保持不变。如果您从地图中删除一个键，绑定将包含 null，但是您的 ComboBox 仍将包含该键的项目...

结合 ObservableMap 绑定

Combo with ObservableMap Binding

java

user-interface

javafx

controlsfx