如何将打印到控制台的值放入 TextArea

Question

我目前正在研究一个利息计算器，我正在尝试将从“i=0”到“i-1”的方法 interestEarned 返回的所有值获取到 TextArea 中。每次我尝试获取“i”的单个值时，它都不会显示我指定的“i”处的值

我只是希望能够提取从“i=0”到“i-1”的一系列值。

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;

import javax.swing.JTextField;

public class Lab7Control extends Lab7View implements ActionListener {
    private static final long serialVersionUID = 1L;

    protected final boolean verbose = true;
    public final int maxAge = 65;
    DecimalFormat df = new DecimalFormat("###,###,###.##");
    public static void main(String args[]) {
        new Lab7Control();
    }

    public Lab7Control() {
        calcB.addActionListener(this);
        clearB.addActionListener(this);

    }

    public void actionPerformed(ActionEvent e) {
        String whichwidget = e.getActionCommand();

        if (whichwidget.equals("Calculate")) {
            displayResultPanel();
        }
        if (whichwidget.equals("Clear")) {
            procReset();
        }

    }

    public void procReset() {
        if (popupFrame != null) {
            popupFrame.dispose();
        }
        checkGroup.clearSelection();
        buttonGroup.clearSelection();
        interestOptionList.clearSelection();
        yearStart.setText("");
        investmentField.setText("");
    }

    public void displayResultPanel() {
        validateInteger(yearStart);
        validateDouble(investmentField);
        validateSelectionList();
        validateSelectionCheck();
        if (validateDouble(investmentField) == true && validateInteger(yearStart) == true
                && validateSelectionList() == true && validateSelectionCheck() == true) {

            if (earlyBox.isSelected()) {
                displayResult();
                resultArea.setText(interestEarned());
            } else {
                displayResult();
                resultArea.setText("Total Value of your Accout: " + interestEarnedat65());
            }
        }

    }

    public boolean validateInteger(JTextField yearStart) {
        try {
            int d = Integer.parseInt(yearStart.getText());
            if (d > maxAge)
                throw new NumberFormatException();
            if (verbose)
                System.out.println("validated Integer " + d);
            return true;
        } catch (NumberFormatException e) {
            if (verbose)
                System.out.println("invalid Integer " + yearStart.getText() + " please retype age less than 65 ");
            yearStart.setText("invalid retry");
            return false;
        }
    }

    public boolean validateDouble(JTextField investmentField) {
        try {
            double d = Double.parseDouble(investmentField.getText());
            if (verbose)
                System.out.println("validated Double " + d);
            return true;
        } catch (NumberFormatException e) {
            if (verbose)
                System.out.println("invalid double " + investmentField.getText() + " please retype ");
            investmentField.setText("invalid retry");
            return false;
        }
    }

    public boolean validateSelectionList() {
        if (interestOptionList.getSelectedValue() != null) {
            return true;
        } else {
            System.out.println("Please make a selection");
            return false;
        }

    }

    public boolean validateSelectionCheck() {
        if (checkGroup.getSelection() != null) {
            return true;
        } else {
            System.out.println("Select when you want to withdraw your money");
            return false;
        }
    }

    public double doubletoDecimal() {
        double d = Double.parseDouble(interestOptionList.getSelectedValue()) / 100;
        return d;
    }

    public String interestEarnedat65() {
        double totalAmount = 0;
        double yearlyInterestPaid = 0;
        double newAmount = 0;
        double q = Double.parseDouble(investmentField.getText());
        int h = Integer.parseInt(yearStart.getText());
        int ageDifferenceforRetirement = 65 - h;
        for (int i = 0; i <= ageDifferenceforRetirement; i++) {
            yearlyInterestPaid = (q * doubletoDecimal());
            newAmount = (yearlyInterestPaid + totalAmount);
            totalAmount = (newAmount * doubletoDecimal()) + newAmount;
            System.out.println(i + " " + totalAmount);
        }

        return df.format(totalAmount);

    }

    public String interestEarned() {
        double totalAmount = 0;
        double yearlyInterestPaid = 0;
        double newAmount = 0;
        int i;
        double q = Double.parseDouble(investmentField.getText());
        int h = Integer.parseInt(yearStart.getText());
        int ageDiff = 65 - h;
        for ( i = 0; i <= ageDiff - 1; i++) {
            yearlyInterestPaid = (q * doubletoDecimal());
            newAmount = (yearlyInterestPaid + totalAmount);
            totalAmount = (newAmount * doubletoDecimal()) + newAmount;
            System.out.println(i + " " + totalAmount);
                    }
        double[] data = new double[i];
        return String.valueOf(data[i-1]);

    }
}