Question

在JTextArea中最多打印363行时，TextArea将在第43行（帧边界）处截断。我已经将JTextArea放入JScrollPane，并将ScrollPolicy设置为ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS ....如何在写入超出帧边界的内容时使JTextArea可滚动？

public static double principalAmt, intRate, balance, monthlyIntRate, monthlyPayment, monthlyIntPayment, monthlyPrincipalPayment;
public static int termLength, months;

static Box infoBox = Box.createVerticalBox();
static Box graphBox = Box.createVerticalBox();

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

public AmortizationTable() {

    // User input
    principalAmt = 150000;
    termLength = 15;
    intRate = 0.05;

    // Calculated values
    balance = principalAmt;
    monthlyIntRate = intRate / 1200;
    months = termLength * 12;
    monthlyPayment = principalAmt * (monthlyIntRate *
            Math.pow(1 + monthlyIntRate, months) / (Math.pow(1 + monthlyIntRate, months) - 1));

    JFrame amortFrame = new JFrame();
    JPanel amortPanel = new JPanel();
    Box amortBox = Box.createVerticalBox();
    JTextArea amortText = new JTextArea();
    amortText.setEditable(false);

    String[] amortArray = new String[months];

    JLabel amortTitle1 = new JLabel("---------------------------------------------------"
            + "-------------------------------------------");
    JLabel amortTitle2 = new JLabel("Payment\tMonthly Payment\tInterest Paid\t\tPrincipal Paid\t\tBalance");
    JLabel amortTitle3 = new JLabel("-------------------------------------------------"
            + "---------------------------------------------");

    amortText.setText(amortText.getText() + amortTitle1.getText() + "\n");
    amortText.setText(amortText.getText() + amortTitle2.getText() + "\n");
    amortText.setText(amortText.getText() + amortTitle3.getText() + "\n");

    for(int i=0; i<months; i++) {

        monthlyIntPayment = balance * monthlyIntRate;
        monthlyPrincipalPayment = monthlyPayment - monthlyIntPayment;
        balance -= monthlyPrincipalPayment;
        if(balance<0)
            balance = -balance;

        amortArray[i] = ("" + (i+1) + "\t" + 
            new DecimalFormat("$0.00").format(monthlyPayment) + "\t\t" +
                new DecimalFormat("$0.00").format(monthlyIntPayment) + "\t\t" +
            new DecimalFormat("$0.00").format(monthlyPrincipalPayment) + "\t\t" +
                new DecimalFormat("$0.00").format(balance) + "\t\n");

        amortText.setText(amortText.getText() + amortArray[i]);

    }

    JScrollPane amortScroll = new JScrollPane(amortText);
    amortScroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
    amortBox.add(amortScroll);
    amortPanel.add(amortBox);
    amortFrame.add(amortPanel);
    amortFrame.setVisible(true);
}

Answer 1

在调用frame.setVisible（true）之前，应始终调用frame.pack()或frame.setSize(...)。通常最好使用frame.pack（）让Swing组件以其首选大小进行绘制。

接下来你实际上需要给文本区域一个关于它的首选大小应该是什么的建议。这可以通过以下方式完成：

JTextArea amortText = new JTextArea(25, 70);

最后，要使用的更好的Swing组件是JTable，因为它支持表格数据。不应将JTextArea用于格式化数据。

JTextArea在JFrame边界截断

1 个答案: