在 JOptionPane 中显示 if 语句

Question

有没有办法在 JOptionPane 中显示 if 语句？我尝试使用 String.format，我还尝试将 if 语句封装在一个方法中，然后使用 JOptionPane 调用该方法，但没有任何效果。我不知道我做错了什么。

我想要类似于下面控制台显示的内容

--- $1,042.18 细分如下 ---

    10 hundred dollar bills
     2 twenty dollar bills 
     2 one dollar bills    
     1 dime                
     1 nickel              
     3 pennies

在消息对话框中显示 window。

我的代码如下：

import javax.swing.JOptionPane;

public class ChangeDisplayJOptionPane {
    public static void main(String[] args) {
        double amount, originalAmount;
        int hundredDollars, fiftyDollars, twentyDollars, tenDollars, 
            fiveDollars, oneDollars, quarters, dimes, nickels, pennies;

        String amountString = JOptionPane.showInputDialog("Enter an     amount:");
        originalAmount = Double.parseDouble(amountString);

        amount = originalAmount;
        amount *= 100;

        hundredDollars = (int)amount / 10_000;
        amount        %= 10_000;
        fiftyDollars   = (int)amount / 5_000;
        amount        %= 5_000;
        twentyDollars  = (int)amount / 2_000;
        amount        %= 2_000;
        tenDollars     = (int)amount / 1_000;
        amount        %= 1_000;
        fiveDollars    = (int)amount / 500;
        amount        %= 500;
        oneDollars     = (int)amount / 100;
        amount        %= 100;
        quarters       = (int)amount / 25;
        amount        %= 25;
        dimes          = (int)amount / 10;
        amount        %= 10;
        nickels        = (int)amount / 5;
        amount        %= 5;
        pennies        = (int)amount;

        JOptionPane.showMessageDialog(null, String.format("%n--- $%,.2f is broken down as follows ---%n%n",
                originalAmount));

        // Must display in dialog window
        System.out.printf("%n--- $%,.2f is broken down as follows ---%n%n",
            originalAmount);

        if (hundredDollars == 1)
            System.out.printf("%10s %-20s%n",hundredDollars,"hundred dollar bill");
        else if (hundredDollars > 1)
            System.out.printf("%10s %-20s%n",hundredDollars,"hundred dollar bills");
        if (fiftyDollars == 1)
            System.out.printf("%10s %-20s%n",fiftyDollars,"fifty dollar bill");
        if (twentyDollars == 1)
            System.out.printf("%10s %-20s%n",twentyDollars,"twenty dollar bill");
        else if (twentyDollars > 1)
            System.out.printf("%10s %-20s%n",twentyDollars,"twenty dollar bills");
        if (tenDollars == 1)
            System.out.printf("%10s %-20s%n",tenDollars,"ten dollar bill");
        if (fiveDollars == 1)
            System.out.printf("%10s %-20s%n",fiveDollars,"five dollar bill");
        if (oneDollars == 1)
            System.out.printf("%10s %-20s%n",oneDollars,"one dollar bill");
        else if (oneDollars > 1)
            System.out.printf("%10s %-20s%n",oneDollars,"one dollar bills");
        if (quarters == 1)
            System.out.printf("%10s %-20s%n",quarters,"quarter");
        else if (quarters > 1)
            System.out.printf("%10s %-20s%n",quarters,"quarters");
        if (dimes == 1)
            System.out.printf("%10s %-20s%n",dimes,"dime");
        else if (dimes > 1)
            System.out.printf("%10s %-20s%n",dimes,"dimes");
        if (nickels == 1)
            System.out.printf("%10s %-20s%n",nickels,"nickel");
        if (pennies == 1)
            System.out.printf("%10s %-20s%n",pennies,"penny");
        else if (pennies > 1)
            System.out.printf("%10s %-20s%n",pennies,"pennies");

        System.exit(0);
    }
}

如有任何帮助，我们将不胜感激。提前致谢。

Answer 1

而不是打印出你的 if 中的每个语句，就像你在这里：

    if (hundredDollars == 1)
        System.out.printf("%10s %-20s%n",hundredDollars,"hundred dollar bill");
    else if (hundredDollars > 1)
        System.out.printf("%10s %-20s%n",hundredDollars,"hundred dollar bills");
    if (fiftyDollars == 1)
        System.out.printf("%10s %-20s%n",fiftyDollars,"fifty dollar bill");

您将构建一个字符串，然后将该字符串放入 JOptionPane 中，如下所示：

String str = "";        
    if (hundredDollars == 1)
        str += String.format(%10s %-20s%n",hundredDollars,"hundred dollar bill");
    else if (hundredDollars > 1)
        str += String.format(%10s %-20s%n",hundredDollars,"hundred dollar bills");
    JOptionPane.showMessageDialog(null, str, originalAmount, JOptionPane.INFORMATION_MESSAGE));

查看示例： https://docs.oracle.com/javase/8/docs/api/javax/swing/JOptionPane.html

并参考这个post： Customize JOptionPane Dialog

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