java - if 语句被调用一次后直接跳到 else ？

Question

我正在制作一个简单的抛硬币游戏，我编写了几个方法来调用并使我的主类变得简短。游戏玩一次后，第一个要求用户输入的 If/Else 语句直接跳到 Else 语句，而不提示输入。

package cointoss;
import java.util.Random;
import java.util.Scanner;
public class Game {
int money;
int result;
int bet;

Random rn = new Random();
Scanner in = new Scanner(System.in);

String playerPick;
String aResult;

public void setMoney(int a)
{
    money = a;
}

public int getMoney()
{
    return money;
}

public void getBet()
{
    System.out.println("How much would you like to bet?");
    bet = in.nextInt();
    do{
    if(bet > money)
    {
        System.out.println("You cannot bet more than you have!");
        System.out.println("You have bet " + (bet - money) + " too many coins.");
        continue;
    }
    else
        System.out.println("You have bet " + bet + " coins.");
    }
    while(bet > money);
}
public void getInput()
{


    System.out.println("Pick Heads or Tails");
    playerPick = in.nextLine();
    playerPick.toLowerCase();

    if(playerPick.contains("heads"))
        playerPick ="heads";
    else if(playerPick.contains("tails"))
        playerPick ="tails";
    else
        System.out.println("Invalid Selection");
    }
public void flipCoin()
{
    result = rn.nextInt(2);
    if(result == 0)
    {
        aResult = "heads";
    }
    else
        aResult = "tails";
}

public void checkResult()
{
    if(playerPick.equals(aResult))
    {
        System.out.println("You have won!");
        money += bet;
        System.out.println("You now have " + money + " coins");

    }
    else{
        System.out.println("You have lost!");
        money -= bet;
        System.out.println("You now have " + money + " coins");
    }
}
}

我的测试人员类(class):

package cointoss;

public class GameTest {
public static void main(String[] args)
{
    Game coinToss = new Game();
    coinToss.setMoney(100);

    while(coinToss.getMoney() > 0)
    {

    coinToss.getInput();
    coinToss.getBet();
    coinToss.flipCoin();
    coinToss.checkResult();
    }
}
}

Answer 1

The method toLowerCase()不改变字符串的内容； String 是 Java 中的不可变类。 toLowerCase() 方法返回结果。你需要改变

playerPick.toLowerCase();

至

playerPick = playerPick.toLowerCase();