Question

我是Android App开发的初学者。下面的代码是一个测验应用程序，我希望它循环随机问题，不要重复问题，我试图使用flag2随机生成问题，但我收到编译错误，任何人都可以帮我解决这个问题。我也是Java的初学者。

TextView tv;
Button btn1;
RadioButton rb1,rb2,rb3;
RadioGroup rg;

String Questions[]={"What is 1+1?","Capital of USA?","What is 2+2","Echo with Laughter","Warg"};
String opt[]={"2","3","4", "New York","Washington DC","Maryland", "5","4","6","Stairway to Heaven","Hotel California","Highway to hell","Jon","Bran","Dario" };
String ans[]={"2","Washington DC","4","Stairway to heaven","Bran"};



int flag=0;
public static int correct;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main2);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    tv=(TextView)findViewById(R.id.textView2);
    btn1=(Button)findViewById(R.id.button2);
    rg=(RadioGroup)findViewById(R.id.radioGroup);
    rb1=(RadioButton)findViewById(R.id.radioButton);
    rb2=(RadioButton)findViewById(R.id.radioButton2);
    rb3=(RadioButton)findViewById(R.id.radioButton3);

    tv.setText(Questions[flag]);
    rb1.setText(opt[0]);
    rb2.setText(opt[1]);
    rb3.setText(opt[2]);

    btn1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            RadioButton uans = (RadioButton) findViewById(rg.getCheckedRadioButtonId());
            String ansText = uans.getText().toString();

            if (ansText.equalsIgnoreCase(ans[flag])) {
                correct++;
            }
            else {
                Intent in = new Intent(getApplicationContext(),Token.class);
                startActivity(in);
            }
            flag++;
            if (flag < Questions.length) {
                tv.setText(Questions[flag]);
                rb1.setText(opt[flag * 3]);
                rb2.setText(opt[(flag * 3)+1]);
                rb3.setText(opt[(flag * 3)+2]);
            }
            else {

                Intent in = new Intent(getApplicationContext(),Token.class);
                startActivity(in);
            }

        }

Answer 1

使用java.lang.Math.random（）。它将返回从0.0到0.1的值，将这些值转换为整数＆amp;得到整数的问题

Answer 2

生成从0到最大问题范围内的随机数，您可以像下面这样做：

int numberOfQuestion = 5; 
Random rn = new Random();
randomNum = rn.nextInt() % numberOfQuestion; // random number from 0 to MaxRange - 1

您可以创建一个类，而不是使用三个数组：

class Quiz{
    String question;
    String answer;
    String[] options;
    boolean asked;
}

每次询问特定问题时，只需将标志asked设为真，然后在询问问题之前，检查是否有问题，如果没有，则只显示问题。

Answer 3

三弦阵列实际上没用。你应该使用object ArrayList。

public class QuestionObject{
    int id;
    String question;
    String [] options;
    String answer;
    --you should implement getter and setter--
    public int getId(){
       return this.id;
    }
    public void setId(int id){
      this.id= id;
    }
    public String getQuestion(){
       return this.question;
    }
    public void setQuesion(String question){
      this.question = question;
    }
   public String[] getOptions() 
   { 
      return options; 
   } 

  public void setOptions(String[] options) 
 { 
   this.options= options; 
   } 

  public int getOptionsElement(int location) 
   { 
      return options[location]; 
  } 

  public void setOptionsElement(int value, int location) 
  { 
    options[location] = value; 
  }
    public String getAnswer(){
       return this.answer;
    }
    public void setAnswer(String answer){
      this.answer= answer;
    }
}

你应该像

一样使用它

ArrayList<QuestionObject> questionObject = new ArrayList<QuestionObject>();
ArrayList<QuestionObject> answeredQuestion = new ArrayList<QuestionObject>();

不要忘记用问题选项和aswers填充questionObject。

之后你的逻辑必须实现。你可以在问题显示时删除问题的id并删除列表。也许你可以把删除的问题推到另一个Arraylist。

//take the diplaying question this id can be your random number
int id = questionObject.getId(); //or int id = yourRandomNumber;
//store the another arraylist this question
answeredQuestion.add(questionObject.get(id));
//remove it from list than never show again 
questionObject.remove(id);

我认为这可能对你有所帮助。

Answer 4

修改

这是因为虽然无限，新的声明为Lists：

Random random = new Random(); String rightAnswer=null; List<String> questions=new ArrayList<String>(); // list of questions List<String> answers=new ArrayList<String>(); // list of answers String[] ques={"What is 1+1?","Capital of USA?","What is 2+2","Echo with Laughter","Warg"}; questions.addAll(Arrays.asList(ques)); String[] ans={"2","Washington DC","4","Stairway to heaven","Bran"}; answers.addAll(Arrays.asList(ans)); ArrayList<String[]> options = new ArrayList<String[]>(); // list of arrays that holds options String[] opt1={"2","3","4"}; String[] opt2={"New York","Washington DC","Maryland"}; String[] opt3={"5","4","6"}; String[] opt4={"Stairway to Heaven","Hotel California","Highway to hell"}; String[] opt5={"Jon","Bran","Dario" }; options.add(opt1); options.add(opt2); options.add(opt3); options.add(opt4); options.add(opt5);

在你想要生成问题的地方，你可以编写这段代码，我在Button的onClick（）中假设：

int questionNumber; if(questions.size()>0) // only run if list contains something { questionNumber = random.nextInt(questions.size()); // generate random question from current list String[] currentOptions=options.get(questionNumber); tv.setText(questions[questionNumber]); rb1.setText(currentOptions[0]); rb2.setText(currentOptions[1]); rb3.setText(currentOptions[2]); rightAnswer=answers.get(questionNumber); // hold right answer in this variable questions.remove(questionNumber); // remove question which is asked answers.remove(questionNumber); // remove answer which is asked options.remove(questionNumber); // remove options that are showed } else { tv.setText("No questions remaining"); }

经过测试，我得到了这些结果：

注意：声明部分必须在生成随机问题的函数之外，否则会失败。

Android - 循环随机数组，不要重复

4 个答案: