java - 返回错误 int 值的变量

Question

编写了以下几行代码，旨在将 2 个值插入到对话框中，并分配给 2 个不同的变量。假设我插入 22，那么它应该在文本字段中显示为 2x2 = 4，相反，它会打印类似 50 x 50 = 2500 的内容。

String a = JOptionPane.showInputDialog("Qual cálculo deseja fazer? (AB = A x B)", "AB");

   aNum = a.charAt(0);
   bNum = a.charAt(1);
   int cNum = aNum*bNum;

    Game.getNumbers(aNum, bNum);

    JOptionPane.showInputDialog(aNum, bNum);

    TF1.setText(Game.First() +" x "+ Game.Second() +" = "+ cNum);

涉及的类:

public class Game1 {

private int first = 0;
private int second = 0;
private int score = 0;
private int hiScore = 0;


public void numTotalCheck(int a){

    String option1 = null;
    char option = 0;

    do{
    if (a == (first*second)){

        JOptionPane.showMessageDialog(null, "Parabéns. Você acertou!");

        score = score + 100;
        if(score > hiScore){

            hiScore = score;
        }
    }else{

        score = score - 100;
        if(score > hiScore){

            hiScore = score;
        }
        JOptionPane.showMessageDialog(null, "Errado!");

        option1 = JOptionPane.showInputDialog("Deseja jogar novamente? <S/N>");
        option = option1.charAt(0);
    }
    }while((option == 's') || (option == 'S'));


}

public void getNumbers(int a, int b){

    first = a;
    second = b;
}

public int First(){

    return first;
}

public int Second(){

    return second;
}

结果:

Result of "22" input.

Answer 1

函数 charAt(index) 返回一个 char，然后您可以将其隐式解析为 int。 '2' 的 int 值为 50，所以它是 50 * 50 = 2500。

一个简单的解决方法是要求输入格式，例如 A;B。然后你可以执行以下操作:

String s =JOptionPane.showInputDialog("Enter two numbers like this: Number A;Number B", "AB");
String[] temp = s.split(";");
if(temp.length == 2) {
  try {
    int aNum = Integer.parseInt(temp[0]);
    int bNum = Integer.parseInt(temp[1]);
    int cNum = aNum*bNum;
  } catch(NumberFormatException nfe) {
    // One or both of the values weren't ints.
  }
} else {
  // Some error here, because of too few/ too many values
}