Fehler beim Versuch, einige Fragen in Android App

Question

zu randomisieren Gruß peeps, brauchen Hilfe zu diesem Fehler. googeln, aber das Problem nicht lösen. Ich habe Bemerkungen gemacht, in welchen Zeilen die Fehler auftreten.

Mitteilung Code unten hat 2 verschiedenen Java-Klasse

[IMG = "Screenshot"] http://i.imgur.com/XYFHZOz.png[/IMG]

public class QuestionAndAnswer { 
public List<String> allAnswers; // distractors plus real answer 
public String answer; 
public String question; 
public String selectedAnswer; 
public int selectedId = -1; 

public QuestionAndAnswer(String question, String answer, List<String> distractors) { 
    this.question = question; 
    this.answer = answer; 
    allAnswers = new ArrayList<String>(distractors); 

    // Add real answer to false answers and shuffle them around 
    allAnswers.add(answer); 
    Collection.shuffle(allAnswers); //error on this line 
} 

public boolean isCorrect() { 
    return answer.equals(selectedAnswer); 
} 

}

public class UjiSalah extends Activity { 
RadioGroup rg; 
int currentQuestion = 0; 
TextView tv; 
List<QuestionAndAnswer> quiz = new ArrayList<QuestionAndAnswer>(); 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.uji_salah); 

    tv = (TextView) findViewById(R.id.tvque); 
    rg = (RadioGroup) findViewById(R.id.radioGroup1); 

    // Setup a listener to save chosen answer 
    rg.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() { 
     @Override 
     public void onCheckedChanged(RadioGroup group, int checkedId) { 
      if(checkedId > -1) { 
       QuestionAndAnswer qna = quiz.get(currentQuestion); 
       qna.selectedAnswer = ((RadioButton) group.findViewById(checkedId)).getText().toString(); 
       qna.selectedId = checkedId; 
      } 
     } 
    }); 

    String[] question = {"Bilangan Rokaat Solah Zuhur ?","Bilangan Rokaat Solat Subuh ?","Bilangan Rokaat Solat Maghrib ?"}; 
      String[] answer = { "4 rokaat","2 rokaat","3 rokaat" }; 
      String[] distractor = { "5 rokaat","1 rokaat","4 rokaat","2 rokaat","3 rokaat","4 rokaat","4 rokaat","5 rokaat","3 rokaat" }; 

      ArrayList<String> distractorList = Arrays.asList(distractor); //error on this line 


    int length = question.length; 
    for(int i = 0; i < length; i++) 
     quiz.add(new QuestionAndAnswer(question[i], answer[i], distractorList.subList(i * 3, (i + 1) * 3))); 
    Collection.shuffle(quiz); //error here 

    fillInQuestion(); 
    } 

    public void fillInQuestion() { 
     QuestionAndAnswer qna = quiz.get(currentQuestion); 
     tv.setText(qna.question); 

     // Set all of the answers in the RadioButtons 
     int count = rg.getChildCount(); 
     for(int i = 0; i < count; i++) 
      ((RadioButton) rg.getChildAt(i)).setText(qna.allAnswers.get(i)); 

     // Restore selected answer if exists otherwise clear previous question's choice 
     if(qna.selectedId > -1) 
      rg.check(qna.selectedId); 
     else 
      rg.clearCheck(); 
    } 
} 

Answer 1

+ 1 @ Prerak Sola, können Sie entweder erklären allAnswers als ArrayList oder wie folgt:

Collection.shuffle((ArrayList)allAnswers); 

Liste nicht Collection-Schnittstelle implementieren, aber Arraylist tut:

https://docs.oracle.com/javase/7/docs/api/java/util/Collection.html

Answer 2

Liste Quiz = new Arraylist <>();

zu

ArrayList<QuestionAndAnswer> quiz = new ArrayList<>();