java - Java 中的事件处理程序

Question

我有一个程序，我正在尝试使用 JavaFX 中的事件处理程序来使按钮执行操作，例如标记为“退出”的按钮用于结束程序。我认为我的代码是正确的，但它不起作用。知道该怎么做吗？代码如下:

import edu.seminolestate.studentanalysis.ActionEvent;
import edu.seminolestate.studentanalysis.EventHandler;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.FlowPane;
import javafx.scene.layout.GridPane;
import javafx.stage.Stage;

public class ProcessPayrollApplication extends Application {

HourlyEmployee hE = new HourlyEmployee(newName, hoursWorked, hourlyRate);

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

    Label lblName = new Label("Employee name: ");
    Label lblHours = new Label("Hours worked: ");
    Label lblHourlyPay = new Label("Hourly pay rate: ");
    Label lblGrossPay = new Label("Gross pay:" + hE.computeGrossPay());
    Label lblTaxes = new Label("Taxes: " + hE.computeTaxAmount());
    Label lblNetPay = new Label("Net pay: " + hE.computeNetPay());
    TextField txtName = new TextField();
    TextField txtHours = new TextField();
    TextField txtPay = new TextField();
    Button btnCalculate = new Button ("Calculate");
    Button btnClear = new Button ("Clear");
    Button btnExit = new Button ("Exit");

    BorderPane bp = new BorderPane();
    GridPane gp = new GridPane();
    gp.setVgap(15);
    gp.setHgap(15);
    FlowPane fp = new FlowPane();
    fp.setHgap(10);
    fp.setAlignment(Pos.CENTER);

    gp.add(lblName, 0, 0);
    gp.add(lblHours, 0, 1);
    gp.add(lblHourlyPay, 0, 2);
    gp.add(lblGrossPay, 0, 3);
    gp.add(lblTaxes, 0, 4);
    gp.add(lblNetPay, 0, 5);
    gp.add(txtName, 1, 0, 2, 1);
    gp.add(txtHours, 1, 1, 2, 1);
    gp.add(txtPay, 1, 2, 2, 1);

    BorderPane.setAlignment(gp, Pos.CENTER);
    bp.setCenter(gp);
    BorderPane.setAlignment(fp, Pos.CENTER);
    bp.setBottom(fp);

    //Add event handlers

    btnExit.setOnAction(new EventHandler<ActionEvent>() {

            @Override
            public void handle(ActionEvent event) {
                System.exit(0);
            }
        }); 

        Scene scene = new Scene(bp, 350, 250);
        primaryStage.setScene(scene);
        primaryStage.show();
        primaryStage.setTitle("Payroll");
    }

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

Answer 1

替换

import edu.seminolestate.studentanalysis.ActionEvent;
import edu.seminolestate.studentanalysis.EventHandler; 

与

import javafx.event.ActionEvent;
import javafx.event.EventHandler;

然后不要忘记将按钮添加到 Pane 中。