JOptionPane 无法显示所有内容

Question

Hello SO Community 我最近将我的程序从 Scanner 输入和显示更改为 JOptionPane 输入和显示，它被设置为显示用户指定年份的投资

目前，如果年数超过 3 年，它将终止程序，我将如何解决这个问题和/或创建一个弹出窗口来显示结果？提前谢谢大家。

import java.util.*;
import javax.swing.JOptionPane;

public class Investing {

public static void main (String[] args){

    double amount;

    double principal;

    double rate;

    Scanner input1 = new Scanner(System.in);

    String principals = JOptionPane.showInputDialog("Please Enter The Principal");
    principal = Double.parseDouble(principals);

    String rates = JOptionPane.showInputDialog("Please Enter The Rate Of Interest");
    rate = Double.parseDouble(rates);

    String years = JOptionPane.showInputDialog("Please Enter The Number Of Investment Years");
    double g = Double.parseDouble(years);
    String zs = JOptionPane.showInputDialog( "Please Enter Annual Contribution");
    double z = Double.parseDouble(zs);

    amount = principal;
    for(int year = 1; year <= g; year++){
        amount *= 1 + rate/100;
        amount+= z;
        JOptionPane.showMessageDialog( null, year + "  " + amount, zs, year);
    }
}
}

Answer 1

你错误地使用了 JOptionPane

JOptionPane.showMessageDialog( null, year + "  " + amount, zs, year);

您将 year 作为消息类型传递，因此在第 3 年之后它会失败。您应该这样做

JOptionPane.showMessageDialog( null, year + "  " + amount, "title", JOptionPane.INFORMATION_MESSAGE );

Answer 2

也许您可以使用StringBuilder 来格式化for 循环中的文本，然后使用它在对话框中显示它。

amount = principal;
StringBuilder sb = new StringBuilder();
for(int year = 1; year <= g; year++){
    amount *= 1 + rate/100;
    amount+= z;
    sb.append(new String(year + " " + amount + '\n'));
}

JOptionPane.showMessageDialog( null, sb.toString(), "Amount Owing", JOptionPane.INFORMATION_MESSAGE);

Answer 3

使用字符串连接来显示messageDialogBox中的所有变量，并且可以使用只有两个参数的messageDialogBox来达到这个目的

for(int year = 1; year <= g; year++){
    amount *= (1 + rate/100);
    amount+= z;
    String a = year + " " + amount + " "+ zs + " " + year;
    JOptionPane.showMessageDialog( null, a);
    }

您正在使用带有变量的 showMessageDialog (year+" ",amount,zs,year) 作为它的参数

JOptionPane.showMessageDialog (null, "Message", "Title", JOptionPane.MessageType);

当年份大于 3 时会出错，因为只有三种类型的消息。有关更多信息，请阅读此 http://www.java2s.com/Tutorial/Java/0240__Swing/UsingJOptionPanetoDisplayaMessage.htm

Answer 4

interest = principal * Math.pow((1 + rate/100),year);
amount += z;

而不是

金额 *= 1 + 比率/100； 数量+= z;

JOptionPane.showMessageDialog(
 null,year + " " + amount,zs,year, "Compound Interest",
 JOptionPane.INFORMATION_MESSAGE );

Refer this