Question

如何让它在4行之一上随机显示答案，没有任何重复？

我目前的代码：

TextView question;
private int qType = -1;
private int asked = 0;
private void QBegin() {
    /*
     * Gets a random question
    */
    question = (TextView) findViewById(R.id.question);
    String[] types = { "Q1", "Q2", "Q3", "Q4", "Q5"};
    Random random = new Random();
    int qType = random.nextInt(types.length);
    question.setText(types[qType]);
    asked++;
   // StringList.add(types[qType]);
    getAnswers(qType);
 /*   if(StringList.contains(types[qType]) && asked >= types.length+1){
        asked = 0;
        answerCounter.setText("THE END");
    } else if (StringList.contains(types[qType]) && asked < types.length+1){
        QBegin();
    } */
}
     public static int random(int range) {
    return (int)(java.lang.Math.random() * (range+1));
}

public void shuffle(String input){
    /*
     * Unused shuffle method
     */
    List<Character> characters = new ArrayList<Character>();
    for(char c:input.toCharArray()){
        characters.add(c);
    }
    StringBuilder output = new StringBuilder(input.length());
    while(characters.size()!=0){
        int randPicker = (int)(Math.random()*characters.size());
        output.append(characters.remove(randPicker));
    }
    System.out.println(output.toString());
}
private void getAnswers(int Type) {
    /* 
     * Getting answers here
     */
    int randomValue = random(4);
    try { 
    String answers_list[][] = {
            {"Answer 1-1", "Answer 2-1", "Answer 3-1", "Answer 4-1"}, 
            {"Answer 1-2", "Answer 2-2", "Answer 3-2", "Answer 4-2"},
            {"Answer 1-3", "Answer 2-3", "Answer 3-3", "Answer 4-3"},
            {"Answer 1-4", "Answer 2-4", "Answer 3-4", "Answer 4-4"},
            {"Answer 1-5", "Answer 2-5", "Answer 3-5", "Answer 4-5"}} ;
    answer1.setText(answers_list[Type][randomValue+1 > 3 ? (randomValue+0)-4 : randomValue+0]); 
    answer2.setText(answers_list[Type][randomValue+2 > 3 ? (randomValue+1)-3 : randomValue+1]); 
    answer3.setText(answers_list[Type][randomValue+3 > 3 ? (randomValue+2)-2 : randomValue+2]); 
    answer4.setText(answers_list[Type][randomValue+0 > 3 ? (randomValue+3)-4 : randomValue+3]);


    /*for (int rows = 0; rows < answer&*list.length; rows++){
    for (int cols = 0; cols < answers_list[rows].length; cols++){   
      }
        }*/
    } catch(Exception ex){
    answer1.setText("Error "+ex);
    }



}

负责挑选的代码＆amp;在4行之一上添加问题（随机）

    answer1.setText(answers_list[Type][randomValue+1 > 3 ? (randomValue+0)-4 : randomValue+0]); 
    answer2.setText(answers_list[Type][randomValue+2 > 3 ? (randomValue+1)-3 : randomValue+1]); 
    answer3.setText(answers_list[Type][randomValue+3 > 3 ? (randomValue+2)-2 : randomValue+2]); 
    answer4.setText(answers_list[Type][randomValue+0 > 3 ? (randomValue+3)-4 : randomValue+3]);

目前，我正在使用answer1和answer4重复。请帮助。

Answer 1

有一种已知的标准改组方法。

随机选择四个中的一个。如有必要，将您选择的那个换成第四个位置的答案。
随机选择剩余答案1至3中的一个。如有必要，将您选择的那个换成第三个位置的答案。
随机选择剩余答案1至2中的一个。如有必要，将您选择的那个与第二个位置的答案交换。

您现在有一个随机列表，其中包含随机顺序的原始四个答案。该算法称为Fisher-Yates shuffle。

ETA简单示例代码：

Random rand = new Random();

String[] answers = { "42",
                     "Only on a Tuesday.",
                     "$4.36",
                     "Hieronymous K. Sluggenheimer III" };

// Shuffle answers[]
for (int i = 3; i > 0; --i) {
    // Pick an answer that hasn't yet been chosen.
    int pick = rand.nextInt(i + 1);
    if (pick != i) {
        // Exchange answers[i] and answers[pick].
        String temp = answers[i];
        answers[i] = answers[pick];
        answers[pick] = temp;
    }
}

Answer 2

如果我正确理解了你的目标，那么你就是在试图随机改变一系列问题。 Rossum为您提供了一种方法，this是对最知名选项的一个很好的介绍。

在我看来，这是最简单的方法：

创建按键排序的地图（例如TreeMap <Double,String>或<Double,Question>）
添加随机密钥并将问题作为值
循环并打印结果。 foreach循环将使用排序顺序

不要担心重复的随机数或将其规范化。重复是不太可能的，如果您需要问题＃，请在循环中添加一个计数器。

无法使此代码正常工作

2 个答案: