如何使用 javafx 将多行文本添加到文本区域？

Question

我正在使用 javafx 创建一个窗格，要求提供贷款金额和年数，以根据年利率从 5% 增加到 8% 计算每月和总还款额。

我想在初始窗格下方以 table 的形式打印出来。但是，我一直在试图弄清楚如何将多行文本添加到文本区域变量。

这是我的代码：

import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.layout.FlowPane;
import javafx.scene.layout.BorderPane;
import javafx.scene.control.ScrollPane;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.control.TextArea;


public class LoanTable extends Application {

    // create TextField and button variables
    private TextField tfAmount = new TextField();
    private TextField tfYears = new TextField();
    private Button btCalc = new Button("Show Table");
    private TextArea taResult = new TextArea();

    @Override
    public void start(Stage primaryStage) {

        // create FlowPane and set properties
        FlowPane pane = new FlowPane();
        pane.setHgap(10);
        tfAmount.setPrefColumnCount(3);
        tfYears.setPrefColumnCount(3);
        pane.getChildren().addAll(new Label("Loan Amount"), tfAmount, new Label("Number of Years"), tfYears, btCalc);

        // create ScrollPane and set properties
        ScrollPane scrollPane = new ScrollPane(taResult);
        taResult.setEditable(false);


        // create BorderPane and add FlowPane and ScrollPane
        BorderPane borderPane = new BorderPane();
        borderPane.setCenter(pane);
        borderPane.setBottom(scrollPane);

        // create and register a handler
        btCalc.setOnAction(e -> calcTable());

        // create a scene and place it in the stage
        Scene scene = new Scene(borderPane);
        primaryStage.setTitle("Loan-Table");
        primaryStage.setScene(scene);
        primaryStage.show();

    }

    // create a method to calculate monthly payment
    public double calcMonthly(double interestRate) {
        double loanAmount = Double.parseDouble(tfAmount.getText());
        int years = Integer.parseInt(tfYears.getText());
        double monthlyInterestRate = interestRate / 1200;
        double monthlyPayment = loanAmount * monthlyInterestRate / (1 - 1 / Math.pow(1 + monthlyInterestRate, years * 12));

        return monthlyPayment;
        }

    // create a method to calculate total payment
    public double calcTotal(double interestRate, double monthlyPayment) {
        int years = Integer.parseInt(tfYears.getText());
        double totalPayment = monthlyPayment * years * 12;

        return totalPayment;
        }

    private void calcTable() {
        // get values from text fields
        double interestRate = 5;

        // display table header
        taResult.setText(String.format("%13s%20s%18s\n", "Interest Rate", "Monthly Payment", "Total Payment"));

        // print rest of table
        for (int i = 1; i < 26; interestRate+=.125, i++) {
            double x = calcMonthly(interestRate);
            taResult.setText(String.format("%5.3f%19.2f%22.2f\n", interestRate, calcMonthly(interestRate), calcTotal(interestRate, x)));
        }
    }


    public static void main(String args[]) {

        Application.launch(args);

    }

}

问题出在“// 打印 table”循环的其余部分。如何向 taResult 变量添加多行文本？当我运行这个程序时，我只是以 table 的最后一行结束。输入 10000（贷款金额）和 5（年数），输出为：

8.000             202.76              12165.84

但我想要的输出是：

Interest Rate     Monthly Payment     Total Payment
5.000             188.71              11322.74
5.125             189.29              11357.13
5.250             189.86              11391.59
5.375             190.44              11426.11
5.500             191.01              11460.70
5.625             191.59              11495.35
5.750             192.17              11530.06
5.875             192.75              11564.84
6.000             193.33              11599.68
6.125             193.91              11634.59
6.250             194.49              11669.56
6.375             195.08              11704.59
6.500             195.66              11739.69
6.625             196.25              11774.85
6.750             196.83              11810.08
6.875             197.42              11845.37
7.000             198.01              11880.72
7.125             198.60              11916.14
7.250             199.19              11951.62
7.375             199.79              11987.16
7.500             200.38              12022.77
7.625             200.97              12058.44
7.750             201.57              12094.18
7.875             202.17              12129.97
8.000             202.76              12165.84

希望我把问题说清楚了。

Answer 1

啊，算了。我想通了。

我需要 taResult.appendText --- .appendText 正是我要找的。

抱歉浪费了阅读本文的任何人的时间。

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