JOptionPane showMessageDialog用法

Question

我是java的初學者。 我有一個最終標記的項目。我做了一些事但我需要你的幫助。 我的項目是關於數學運算。我應該使用JOptionPane。 我可以第一部分InputDialog但我不能在消息框中顯示它們（我只使用println來查看如何工作）。當然，這個部門非常重要。如果你試圖除以零應該是錯誤的，應該寫一些關於錯誤。我在等你的幫助。非常感謝和問候。

import javax.swing.JOptionPane; 

public class JavaMath3 { 

    public static void main(String[] args) { 

     int num1, num2, add, sub, multi; 
     double div; 



     num1 = Integer.parseInt(JOptionPane.showInputDialog("Write 1st number.")); 
     num2 = Integer.parseInt(JOptionPane.showInputDialog("Write 2nd number.")); 


     add = num1+num2; 
      System.out.println("Addition " + add); 

     sub = num1-num2; 
      System.out.println("Subtraction " + sub); 

     multi = num1*num2; 
      System.out.println("Multiplication " + multi); 

     if(num2 != 0) { 
      div = (double) num1/num2; 
      System.out.println("Division: " + div); 
     } 
     else { 
      System.out.println("A number can not divided by zero."); 
     } 

    } 

} 

Answer 1

這是一個非常簡單的，你可以使用的JOptionPane方法showMessageDialog

JOptionPane.showMessageDialog(parent, "your message"); 

，這裏是一個示例代碼

public static void main(String[] args) 
{ 
    int num1 = Integer.parseInt(JOptionPane.showInputDialog("Write 1st number.")); 
    int num2 = Integer.parseInt(JOptionPane.showInputDialog("Write 2nd number.")); 
    int sum = num1 + num2; 
    JOptionPane.showMessageDialog(null, "sum = " + sum); 
} 

後更新

這裏有一個完整的例子

public static void main(String[] args) 
{ 
    int num1, num2, add, sub, multi; 
    double div; 

    num1 = Integer.parseInt(JOptionPane.showInputDialog("Write 1st number.")); 
    num2 = Integer.parseInt(JOptionPane.showInputDialog("Write 2nd number.")); 

    add = num1 + num2; 

    sub = num1 - num2; 

    multi = num1 * num2; 

    String result = "sum = " + add + "\n" + "sub = " + sub + "\nmul = " + multi; 
    if (num2 != 0) 
    { 
     div = (double) num1/num2; 
     result = result + " \n div = " + div; 
    } else 
    { 
     result = result + " \n div = A number can not divided by zero"; 
     System.out.println("A number can not divided by zero."); 
    } 

    JOptionPane.showMessageDialog(null, result); 

} 

Answer 2

我沒有得到的盒子是什麼意思，但如果你想他們都在同一個對話框，你可以只寫這行你else語句後：

JOptionPane.showMessageDialog(null, "Addition: " + add+ "\nSubtraction: " + sub+"\nMultiplication " + multi+ "\nDivision: " + div);