Question

我对javafx很新，但是想要制作这个下拉列表（组合框），这样当你做出选择时，文本框或列表中的文本会发生变化 - 例如。当在下拉菜单中选择水果或饮料时，会出现含有不同水果或饮料的清单。

我无法使用fxml。任何人都可以让我开始如何做到这一点？

这是我的主要课程

package grocerylist;

import javafx.application.Application;
import static javafx.application.Application.launch;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.Label;
import javafx.scene.control.ListView;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.ColumnConstraints;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.Priority;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.scene.text.Text;
import javafx.stage.Stage;


public class GroceryList extends Application { 
FruitVeg fruitVegList;
Beverages beverageList;
Bread breadList;
ComboBox comboBox;
TextField tf1;
ListView lv2;

@Override
public void start(Stage stage){

    fruitVegList = new FruitVeg();
    beverageList = new Beverages();
    breadList = new Bread();



    BorderPane root = new BorderPane();
    Scene scene = new Scene(root, 750, 750);

    GridPane grid = new GridPane();
    grid.setPadding(new Insets(20,20,20,20));
    grid.setHgap(10);
    grid.setVgap(10);
    ColumnConstraints column1 = new ColumnConstraints(50);
    ColumnConstraints column2 = new ColumnConstraints(200, 200,
    Double.MAX_VALUE);
    ColumnConstraints column3 = new ColumnConstraints(200, 200,
    Double.MAX_VALUE);
    column1.setHgrow(Priority.ALWAYS);
    column3.setHgrow(Priority.ALWAYS);
    grid.getColumnConstraints().addAll(column1, column2, column3);
    grid.setGridLinesVisible(true);


    Text scenetitle = new Text("My Shopping List");
    scenetitle.setFont(Font.font("Tahoma", FontWeight.NORMAL, 20));
    grid.add(scenetitle, 0, 0, 4, 1);


    Label op1 = new Label("1.");
    op1.setFont(Font.font("Tahoma", FontWeight.NORMAL, 20));
    grid.add(op1, 0, 1);

    comboBox = new ComboBox();
    comboBox.getItems().addAll(
                "Fruits and Vegetables",
                "Beverages",
                "Bread"

    );
    comboBox.setPromptText("Choose a department");
    grid.add(comboBox, 1, 1);

   /* comboBox.setOnAction ((ActionEvent event) -> {
        comboBox.getSelectionModel().getSelectedItem();
        if (comboBox.getValue().equals("Fruits")) {
            lv1.setItem(fruitVegList.getFruit());
        }
    }); */


    Label op2 = new Label("2.");
    op2.setFont(Font.font("Tahoma", FontWeight.NORMAL, 20));
    grid.add(op2, 0, 2);

    tf1 = new TextField();
    grid.add(tf1, 1, 2);

    Label op3 = new Label("3.");
    op3.setFont(Font.font("Tahoma", FontWeight.NORMAL, 20));
    grid.add(op3, 2, 2);

    lv2 = new ListView();
    grid.add(lv2, 3, 2);

    comboBox.setOnAction(event -> {
        comboBox.getSelectionModel().selectedItemProperty().addListener((ObservableValue observable, Object oldvalue, Object newValue) -> {
            if (newValue == "Fruit and Vegetables") {
                tf1.setText(fruitVegList);
            }
        });

    });

    root.getChildren().addAll(grid);

    stage.setTitle("MY SHOPPING LIST");
    stage.setScene(scene);
    stage.show();
}

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

我有一个抽象类作为我的任务的一部分，但这就是为什么我不能使它工作？

package grocerylist;

import java.util.ArrayList;
import java.util.List;


public abstract class Groceries {

List<String> fruitVegList = new ArrayList<>();   
}

水果和蔬菜类

package grocerylist;

import java.util.List;

public class FruitVeg extends Groceries {

public FruitVeg(){
    fruitVegList.add("Apple");
    fruitVegList.add("Banana");
    fruitVegList.add("Cucumber");
    fruitVegList.add("Carrot");
    fruitVegList.add("Kale");
    fruitVegList.add("Salad");
    fruitVegList.add("Pear");

}

public List<String> getFruit() {
    return fruitVegList;
}

}

如何从comboBox中选择它会显示水果列表的内容？

Answer 1

这是一个可以让你入门的可运行的课程

XPdfForm

下拉列表中的Javafx选择提供了不同的文本框

1 个答案: