Question

我需要在我的Java类的最后学校作业中实现一个接口。被覆盖的界面应该打印一条短信，描述一名足球运动员如何庆祝在NFL被选中，这样的话：

System.out.println("name dances to celebrate his draft");

然而，当我将其放入允许用户将玩家添加到其名单中的方法时，我的界面不会打印消息。以下是程序中重写的界面：

//Overridden celebrate method
    @Override
    public void celebrate(int i, int place){
        int randomInteger;

        if (place == 0) //Player is offensive
        {
            randomInteger = random1Thru6();

            //players() is a method that contains all the players in the team
            //'place' refers to the players location in the array of players on the team
            switch (randomInteger) 
            {

                case 1: System.out.println(players(i).get(place) + " dances to celebrate his draft!");
                break;

                case 2: System.out.println(players(i).get(place) + " cartwheels to celebrate his draft!");
                break;

                case 3: System.out.println(players(i).get(place) + " throws a party to celebrate his draft!");
                break;

                case 4: System.out.println(players(i).get(place) + " sings to celebrate his draft!");
                break;

                case 5: System.out.println(players(i).get(place) + " gets root beer for everyone to celebrate his draft!");
                break;

                case 6: System.out.println(players(i).get(place) + " gets donuts to celebrate his draft!");
            }
        }

        else if (place == 1) //Player is defensive
        {
            randomInteger = random1Thru6();

            switch (randomInteger) 
            {

                case 1: System.out.println(players(i).get(place) + " dances to celebrate his draft!");
                break;

                case 2: System.out.println(players(i).get(place) + " cartwheels to celebrate his draft!");
                break;

                case 3: System.out.println(players(i).get(place) + " throws a party to celebrate his draft!");
                break;

                case 4: System.out.println(players(i).get(place) + " sings to celebrate his draft!");
                break;

                case 5: System.out.println(players(i).get(place) + " gets root beer for everyone to celebrate his draft!");
                break;

                case 6: System.out.println(players(i).get(place) + " gets pizza to celebrate his draft!");
            }
        }



    }

我应该对进攻和防守位置有一个不同的庆祝回应，如上面的代码所示。这是引用的random1Thru6（）方法：

public int random1Thru6() { //used to get a random number from 1 to 6
        int randomInteger = (int)Math.random() * 10;
        //this is supposed to call the method over and over again until it gives a number from 1-6 but it has been printing 7-9 as well
        if (randomInteger > 6)
            random1Thru6();

        return randomInteger;
    }

这是players（）方法：

//holds and prints all the players
    public ArrayList<String> players(int i) {

        ArrayList<String> returnedList = new ArrayList<>();

        // Christian McCaffrey is a Running Back, Corn Elder is a Corner Back for the Carolina Panthers
        ArrayList<String> Players1 = new ArrayList<String>();
        Players1.add("Christian McCaffrey");
        Players1.add("Corn Elder");

        //Jake Butt is a Tight End, Brendan Langley is a Corner Back for the Denver Broncos
        ArrayList<String> Players2 = new ArrayList<String>();
        Players2.add("Jake Butt");
        Players2.add("Brendan Langley");

        //Ryan Switzer is a Wide Receiver, Taco Charlton is a Defensive End for the Dallas Cowboys
        ArrayList<String> Players3 = new ArrayList<String>();
        Players3.add("Ryan Switzer");
        Players3.add("Taco Charlton");

        //Dalvin Cook is a Running Back, Ifeadi Odenigbo is a Defensive Line for the Minnesota Vikings
        ArrayList<String> Players4 = new ArrayList<String>();
        Players4.add("Dalvin Cook");
        Players4.add("Ifeadi Odenigbo");

        switch (i)
        {
        case 1: returnedList.addAll(Players1);
                break;

        case 2: returnedList.addAll(Players2);
                break;

        case 3: returnedList.addAll(Players3);
                break;

        case 4: returnedList.addAll(Players4);
                break;      
        }

        return returnedList;

    }

以下是celeb（）方法的调用方法：

for (int l = 0; l < players(i).size(); l++)
        {
            if (choosePlayer.equalsIgnoreCase(players(i).get(l)))
            {
                addPlayer(players(i).get(l));
                celebrate(i, l);
                enterRoster();
            }
        }

并且：

addPlayer(players(i).get(place));
celebrate(i, place);
enterRoster();

addPlayer（int i，int place）是一种为团队添加播放器的方法＆＃39; i＆＃39;在＆＃39; place＆＃39;的位置在团队的球员阵列中进入用户名单的ArrayList。

注意：我按照评论中的建议检查了random1Thru6（）调用的号码，现在我明白为什么它不打印庆祝消息，因为我有(int)Math.random() * 10它总是返回0所以我改成了：

double randomDouble = Math.random() * 10;
int randomInteger = (int)randomDouble;

现在它打印庆祝消息但random1Thru6（）现在返回所有数字1-9，请解释我如何递归调用此方法本身，直到它返回数字1-6。

感谢delephin的评论！

注意：我已接受下面显示的delephin的答案，谢谢大家的帮助！

Answer 1

添加到您的主要课程：

static Random r = new Random();

static {
    r.setSeed(System.currentTimeMillis());
}

并将随机函数方法更改为以下内容：

public int random1Thru6() {
    return r.nextInt(6) + 1;
}

通过快速测试，您之前的随机数发生器返回零。

接口方法问题

1 个答案: