随机（collection.shuffle）问题和答案按钮 Android Studio

Question

我正在开发一个问答游戏，它具有简单、中等和困难三种不同的难度。我使用了 collection.shuffle 但它似乎不起作用。

注意 - 当我有一个级别（简单）时它可以工作，但现在我有三个级别它不工作我已经研究并玩过但没有运气。我是编码新手，所以有解释的答案会很有帮助。

以下代码来自 QuizHelper 类

块引用

package com.example.sqz;




import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class QuizHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "SQZ";
// tasks table name
private static final String TABLE_QUEST = "quest";
// tasks Table Columns names
private static final String KEY_ID = "qid";
private static final String KEY_QUES = "question";
private static final String KEY_ANSWER = "answer"; // correct option
private static final String KEY_OPTN1 = "OPTN1"; // option 1
private static final String KEY_OPTN2 = "OPTN2"; // option 2
private static final String KEY_OPTN3 = "OPTN3"; // option 3
private static final String KEY_OPTN4 = "OPTN4";
private static final String LEVEL = "LEVEL";

private SQLiteDatabase dbase;

public QuizHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}



@Override
public void onCreate(SQLiteDatabase db) {
    dbase = db;
    String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_QUEST + " ( "
            + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_QUES
            + " TEXT, " + KEY_ANSWER + " TEXT, " + KEY_OPTN1 + " TEXT, "
            + KEY_OPTN2 + " TEXT, " + KEY_OPTN3 + " TEXT, " + KEY_OPTN4 + "  TEXT, "+ LEVEL+ " TEXT)";
    db.execSQL(sql);
    addQuestion();
    // db.close();
}

private void addQuestion() {
    Question q1 = new Question("Which team won FIFA world cup in 2002 ?", "Brazil", "England","Germany", "Italy", "Brazil",1);
    this.addQuestion(q1);
    Question q2 = new Question("How many goals Messi scored UEFA Champions League 2015  ?", "7", "6", "5", "8", "6",1);
    this.addQuestion(q2);
    Question q3 = new Question("Which team won cricket world cup in 2015  ?", "Australia", "England","New Zealand", "South Africa", "Australia",1);
    this.addQuestion(q3);
    Question q4 = new Question("Which team won premier league in 2015  ?", "Arsenal", "Manchester city", "Liverpool", "Chelsea", "Chelsea",1);
    this.addQuestion(q4);
    Question q5 = new Question("What team does LeBron James play for ?", "Cleveland Cavaliers", "Charlotte Hornets", "Los Angeles Clippers", "Miami Heat", "Cleveland Cavaliers",1);
    this.addQuestion(q5);
    Question q6 = new Question("Who scored the most goals in 2013  ?", "Lionel Messi", "Zlatan Ibrahimovic", "thierry henry", "Cristiano Ronaldo", "Cristiano Ronaldo",1);
    this.addQuestion(q6);
    Question q7 = new Question("Which team won world twenty20 in 2012  ?", "Australia", "West Indies", "South Africa", "Sri Lanka", "West Indies",1);
    this.addQuestion(q7);
    Question q8 = new Question("Who won Formula 1 championship in 2013  ?", "Fernando Alonso", "Sebastian Vettel", "Esteban Gutierrez", "Lewis Hamilton", "Sebastian Vettel",1);
    this.addQuestion(q8);
    Question q9 = new Question("Who won world darts championship in 2015 ?", "Gary Anderson", "Phil Taylor", "Boris Koltsov", "Michael van Gerwen", "Gary Anderson",1);
    this.addQuestion(q9);
    Question q10 = new Question("Cristiano Ronaldo played for which team in 2007  ?", "Arsenal", "Chelsea", "Liverpool", "Man United", "Man United",1);
    this.addQuestion(q10);
    Question q11 = new Question("how many goals Steven gerrard has scored for liverpool ?", "186", "195", "188", "174", "186",1);
    this.addQuestion(q11);
    Question q12 = new Question("Steve Smith plays for which cricket team  ?", "England", "New Zealand", "South Africa", "Australia", "Australia",1);
    this.addQuestion(q12);
    Question q13 = new Question("How many goals Neymar scored for Santos   ?", "137", "136", "140", "138", "136",1);
    this.addQuestion(q13);
    Question q14 = new Question("Steven Finn plays for which cricket team  ?", "England", "New Zealand", "South Africa", "Australia", "England",1);
    this.addQuestion(q14);
    Question q15 = new Question("Which football team Wayne Rooney play for  ?", "Man City", "Liverpool", "Man United", "Arsenal", "Man United",1);
    this.addQuestion(q15);
    Question q16 = new Question("Which tennis player was ranked number 1 in 2016  ?", "Roger Federer", "Tomas Berdych", "Novak Djokovic", "Rafael Nadal", "Novak Djokovic",1);
    this.addQuestion(q16);
    Question q17 = new Question("Who won Wimbledon Championships  ? 2013", "Roger Federer", "Tomas Berdych", "Novak Djokovic", "Andy Murray", "Andy Murray",1);
    this.addQuestion(q17);
    Question q18 = new Question("Which team won FIFA world cup in 2014   ?", "Spain", "Germany", "Brazil", "Italy", "Germany",1);
    this.addQuestion(q18);
    Question q19 = new Question("Which team won twenty20 cricket in 2009  ?", "Pakistan", "Indian", "England", "Sri Lanka", "Pakistan",1);
    this.addQuestion(q19);
    Question q20 = new Question("Which team won cricket world cup in 2007  ?", "India", "Sri Lanka", "New Zealnad", "Australia", "Australia",1);
    this.addQuestion(q20);
    Question q21 = new Question("Who won tour de france 2014  ?", "Bradley Wiggins", "Leopold Konig", "Vincenzo Nibali", "Alberto Contador", "Vincenzo Nibali",1);
    this.addQuestion(q21);
    Question q22 = new Question("who was the manager of liverpool in 2009  ?", "Rafael Benitez", "Leopold Konig", "Roy Hodgson", "Brendan Rodgers", "Rafael Benitez",1);
    this.addQuestion(q22);
    Question q23 = new Question("Angelo Mathews plays test cricket for which team  ?", "Australia", "West Indies", "Sri Lanka", "England", "Sri Lanka",2);
    this.addQuestion(q23);
    Question q24 = new Question("Which football team Luis Suarez played for from 2007-2011  ?", "Italy", "Barcelona", "Ajax", "Liverpool", "Ajax",2);
    this.addQuestion(q24);
    Question q25 = new Question("Which team won premier league in 2008  ?", "Manchester United", "Liverpool", "Arsenal", "Chelsea", "Manchester United",2);
    this.addQuestion(q25);
    Question q26 = new Question("What team does Kobe Bryant play for  ?", "Swansea City", "Wycombe Wonderes", "Arsenal", "Southampton", "Swansea City",2);
    this.addQuestion(q26);
    Question q27 = new Question("Who won Formula 1 championship in 2007  ?", "Falipo Massa", "Kimi Räikkönen", "Fernando Alonso", "Lewis Hamilton", "Kimi Räikkönen",2);
    this.addQuestion(q27);
    Question q28 = new Question("Which football team does Wilfried Bony play for ?", "Bradley Wiggins", "Leopold Konig", "Vincenzo Nibali", "Alberto Contador", "Vincenzo Nibali",2);
    this.addQuestion(q28);
    Question q29 = new Question("What is the highest possible break in snooker   ?", "156", "154", "155", "153", "155",2);
    this.addQuestion(q29);
    Question q30 = new Question("Cristiano Ronaldo played for which football team in 2007  ?", "Manchester United", "Liverpool", "Brazil", "Spain", "Manchester United",2);
    this.addQuestion(q30);
    Question q31 = new Question("In snooker what is the value of green ball  ?", "4", "3", "5", "6", "3",2);
    this.addQuestion(q31);
    Question q32 = new Question("The game of badminton became popular in the United States during what time ?", "1930", "1931", "1929", "1932", "1930",2);
    this.addQuestion(q32);
    Question q33 = new Question("What is height of badminton net ?", "5.2ft", "5ft", "5.3ft", "5.5ft", "5ft",2);
    this.addQuestion(q33);
    Question q34 = new Question("How many points are there in a table tennis game ?", "9", "10", "11", "12", "11",2);
    this.addQuestion(q34);
    Question q35 = new Question("What is the weight of a table tennis ball ?", "2 gram", "2.5 gram", "2.7 gram", "2.9 gram", "2.7 gram",2);
    this.addQuestion(q35);
    Question q36 = new Question("In yards, how far apart are the cricket wickets ?", "18", "20", "22", "24", "22",2);
    this.addQuestion(q36);
    Question q37 = new Question("How old was Pele when he won his first World Cup ?", "15", "17", "18", "16", "17",2);
    this.addQuestion(q37);
    Question q38 = new Question("How many ways can a batsman be out ?", "7", "9", "10", "8", "10",2);
    this.addQuestion(q38);
    Question q39 = new Question("Which baseball player hit his 700th home run on September 17, 2004 ?", "Joe DiMaggio", "Barry Bond", "Ty Cobb", "Carl Yastrzemski", "Barry Bond",2);
    this.addQuestion(q39);
    Question q40 = new Question("How many games are in a Major League Baseball season per team ?", "154", "160", "162", "158", "162",2);
    this.addQuestion(q40);
    Question q41 = new Question("Which rugby player got criticism for his 'swallow dives' in 2011 ?", "Samson Lee", "Chris Ashton", "Warren Gatland", "Mike Brown", "Chris Ashton",2);
    this.addQuestion(q41);
    Question q42 = new Question("In darts, what is the lowest score that cannot be scored with a single dart ?", "21", "24", "23", "19", "23",2);
    this.addQuestion(q42);
    Question q43 = new Question("James Naismith invented which sport ?", "Baseball", "Basketball", "Table tennis", "Hockey", "Basketball",2);
    this.addQuestion(q43);
    Question q44 = new Question("Which company supplied the Euro 2012 matchball ?", "Nike", "Adidas", "Puma", "Umbro", "Adidas",3);
    this.addQuestion(q44);
    Question q45 = new Question("How old was Linford Christie when he won gold for the 100m in Barcelona ?", "35", "31", "32", "33", "32",3);
    this.addQuestion(q45);
    Question q46 = new Question("To the nearest 1,000 how many rides did the legendary Willie Shoemaker take ?", "40,000", "30,000", "50,000", "20,000", "40,000",3);
    this.addQuestion(q46);
    Question q47 = new Question("In which year was the first Wimbledon tournament held ?", "1818", "1877", "1845", "1919", "1877",3);
    this.addQuestion(q47);
    Question q48 = new Question("How many World Cups have been won by Australian ?", "5", "4", "6", "7", "4",3);
    this.addQuestion(q48);
    Question q49 = new Question("What sport used the term 'home run' long before baseball ?", "Cricket", "Hockey", "Basketball", "Darts", "Cricket",3);
    this.addQuestion(q49);
    Question q50 = new Question("In horse racing, what is a Yankee ?", "13 individual bets", "12 individual bets", "11 individual bets", "10 individual bets", "11 individual bets",3);
    this.addQuestion(q50);
    Question q51 = new Question("How many players make up a Canadian Football team ?", "13", "14", "12", "15", "14",3);
    this.addQuestion(q51);
    Question q52 = new Question("In which year was the Cotton Bowl first contested? ?", "1938", "1937", "1945", "1930", "1937",3);
    this.addQuestion(q52);
    Question q53 = new Question("where was the summer Olympics of 1928 held ?", "New York", "Amsterdam", "London", "Brazil", "Amsterdam",3);
    this.addQuestion(q53);
    Question q54 = new Question("In which year did martin Johnson retire from International Rugby? ?", "2005", "2004", "2007", "2001", "2004",3);
    this.addQuestion(q54);
    Question q55 = new Question("How many players feature in a male Lacrosse team? ?", "8", "10", "11", "13", "10",3);
    this.addQuestion(q55);
    Question q56 = new Question("Ken Walton was a long time commentator most famously associated with which sport? ?", "Basketball", "Wrestling", "Cricket", "Tennis", "Wrestling",3);
    this.addQuestion(q56);
    Question q57 = new Question("The Superbowl is usually contested in which month? ?", "May", "January", "March", "April", "January",3);
    this.addQuestion(q57);
    Question q58 = new Question("In inches, how big is the diameter of a basketball hoop? ?", "8", "8.5", "9", "7", "8",3);
    this.addQuestion(q58);
    Question q59 = new Question("What number lies between 5 and 9 on a British dart board? ?", "15", "12", "10", "14", "12",3);
    this.addQuestion(q59);
    Question q60 = new Question("In golf, over how many holes is The Open Championship contested? ?", "65", "68", "72", "75", "72",3);
    this.addQuestion(q60);
    Question q61 = new Question("Kareem Abdul-Jabbar played 20 seasons in which sport? ?", "Cricket", "Basketball", "Tennis", "Hockey", "Basketball",3);
    this.addQuestion(q61);


    // END
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldV, int newV) {
    // Drop older table if existed
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_QUEST);
    // Create tables again
    onCreate(db);
}

// Adding new question
public void addQuestion(Question quest) {
    // SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(KEY_QUES, quest.getQUESTION());
    values.put(KEY_ANSWER, quest.getANSWER());
    values.put(KEY_OPTN1, quest.getOPT1());
    values.put(KEY_OPTN2, quest.getOPT2());
    values.put(KEY_OPTN3, quest.getOPT3());
    values.put(KEY_OPTN4, quest.getOPT4());
    values.put(LEVEL, quest.getLevel());

    // Inserting Row
    dbase.insert(TABLE_QUEST, null, values);
}

public List<Question> getAllQuestions() {
    List<Question> questionList = new ArrayList<Question>();
    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_QUEST;
    dbase = this.getReadableDatabase();
    Cursor cursor = dbase.rawQuery(selectQuery, null);
    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            Question quest = new Question();
            quest.setID(cursor.getInt(0));
            quest.setQUESTION(cursor.getString(1));
            quest.setANSWER(cursor.getString(2));
            quest.setOPTN1(cursor.getString(3));
            quest.setOPTN2(cursor.getString(4));
            quest.setOPTN3(cursor.getString(5));
            quest.setOPTN4(cursor.getString(6));



                questionList.add(quest);
        } while (cursor.moveToNext());
    }
    // return quest list
    ArrayList<Integer> list=new ArrayList<Integer>();
    for(int i=0;i<60;i++)
        list.add(i);

    Collections.shuffle(list);

    List<Question> shuffledQuestionList = new ArrayList<Question>();


    for(int i=0;i<60;i++)
        shuffledQuestionList.add(questionList.get(list.get(i)));



    return shuffledQuestionList;

}

public List<Question> getAllQuestionsByLevel(int level) {
    List<Question> questionList = new ArrayList<Question>();
    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_QUEST+" where "+LEVEL+" ='"+String.valueOf(level)+"'";
    dbase = this.getReadableDatabase();
    Cursor cursor = dbase.rawQuery(selectQuery, null);
    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            Question quest = new Question();
            quest.setID(cursor.getInt(0));
            quest.setQUESTION(cursor.getString(1));
            quest.setANSWER(cursor.getString(2));
            quest.setOPTN1(cursor.getString(3));
            quest.setOPTN2(cursor.getString(4));
            quest.setOPTN3(cursor.getString(5));
            quest.setOPTN4(cursor.getString(6));
            quest.setLevel(cursor.getInt(7));

            if(quest.getLevel()==level)
                questionList.add(quest);
        } while (cursor.moveToNext());
    }
    return questionList;

}

}

块引用

package com.example.sqz;



import android.app.Activity;

public class Question extends Activity {

private int ID;
private String QUESTION;
private String OPTION1;
private String OPTION2;
private String OPTION3;
private String OPTION4;
private int level;

private String ANSWER;


public Question() {
    ID = 0;
    QUESTION = "";
    OPTION1 = "";
    OPTION2 = "";
    OPTION3 = "";
    OPTION4 = "";

    ANSWER = "";
    level=0;

}

public Question(String qUESTION, String OPTN1, String OPTN2, String OPTN3,String OPTN4,
                String aNSWER,int level) {
    QUESTION = qUESTION;
    OPTION1 = OPTN1;
    OPTION2 = OPTN2;
    OPTION3 = OPTN3;
    OPTION4 = OPTN4;

    ANSWER = aNSWER;
    this.level=level;

}

public int getLevel() {
    return level;
}

public void setLevel(int level) {
    this.level = level;
}

public int getID() {
    return ID;
}

public String getQUESTION() {
    return QUESTION;
}

public String getOPT1() {
    return OPTION1;
}

public String getOPT2() {return OPTION2;}

public String getOPT3() {return OPTION3;}

public String getOPT4() {return OPTION4;}

public String getANSWER() {
    return ANSWER;
}

public void setID(int id) {
    ID = id;
}

public void setQUESTION(String qUESTION) {
    QUESTION = qUESTION;
}

public void setOPTN1(String OPTN1) {
    OPTION1 = OPTN1;
}

public void setOPTN2(String OPTN2) {OPTION2 = OPTN2;    }

public void setOPTN3(String OPTN3) {OPTION3 = OPTN3;}

public void setOPTN4(String OPTN4) {OPTION4 = OPTN4;}

public void setANSWER(String aNSWER) {
    ANSWER = aNSWER;
}

}

块引用

package com.example.sqz;



import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.os.CountDownTimer;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.util.List;
import java.util.concurrent.TimeUnit;


public class QuestionActivity extends Activity {
List<Question> quesList;
int score = 0;
int qid = 0;


Question currentQuestion;
TextView txtQuestion, times, scored;
Button Answer1, Answer2, Answer3, Answer4;
QuizHelper db;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    int level=getIntent().getIntExtra("level",-1);

    if(level!=-1)   {
        db=new QuizHelper(this);
        quesList=db.getAllQuestionsByLevel(level);
    }


    currentQuestion = quesList.get(qid); // the current question

    txtQuestion = (TextView) findViewById(R.id.txtQuestion);
    // the textview in which the question will be displayed


    // the three buttons,
    // the idea is to set the text of three buttons with the options from question bank
    Answer1 = (Button) findViewById(R.id.btnAnswer1);
    Answer2 = (Button) findViewById(R.id.btnAnswer2);
    Answer3 = (Button) findViewById(R.id.btnAnswer3);
    Answer4 = (Button) findViewById(R.id.btnAnswer4);

    // the textview in which score will be displayed
    scored = (TextView) findViewById(R.id.score);

    // the timer
    times = (TextView) findViewById(R.id.timers);


    // method which will set the things up for our game
    setQuestionView();
    times.setText("00:0:00");

    // A timer of 60 seconds to play for, with an interval of 1 second (1000 milliseconds)
    CounterClass timer = new CounterClass(10000, 1000);
    timer.start();




    // button click listeners
    Answer1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            // passing the button text to other method
            // to check whether the anser is correct or not
            // same for all three buttons
            getAnswer(Answer1.getText().toString());
        }
    });

    Answer2.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getAnswer(Answer2.getText().toString());
        }
    });

    Answer3.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getAnswer(Answer3.getText().toString());
        }
    });
    Answer4.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getAnswer(Answer4.getText().toString());
        }
    });
}

public void getAnswer(String AnswerString) {
    if (currentQuestion.getANSWER().equals(AnswerString)) {

        // if conditions matches increase the int (score) by 1
        // and set the text of the score view
        score++;
        scored.setText("Score : " + score);
    } else {

        // if unlucky start activity and finish the game

        Intent intent = new Intent(QuestionActivity.this,
                ResultActivity.class);

        // passing the int value
        Bundle b = new Bundle();
        b.putInt("score", score); // Your score
        intent.putExtras(b); // Put your score to your next
        startActivity(intent);
        finish();
    }
    if (qid < 20) { // please add atleast 21 questions for each set of levels or else the value will be less than 20 and your game will stop working :)

        // if questions are not over then do this
        currentQuestion = quesList.get(qid);
        setQuestionView();
    } else {

        // if over do this
        Intent intent = new Intent(QuestionActivity.this,
                ResultActivity.class);
        Bundle b = new Bundle();
        b.putInt("score", score); // Your score
        intent.putExtras(b); // Put your score to your next
        startActivity(intent);
        finish();
    }


}


@TargetApi(Build.VERSION_CODES.LOLLIPOP)
@SuppressLint("NewApi")
public class CounterClass extends CountDownTimer {

    public CounterClass(long millisInFuture, long countDownInterval) {
        super(millisInFuture, countDownInterval);

    }


    @Override
    public void onFinish() {
        times.setText("Time is up");

    }

    @Override
    public void onTick(long millisUntilFinished) {


        long millis = millisUntilFinished;
        String hms = String.format(
                "%02d:%02d:%02d",
                TimeUnit.MILLISECONDS.toHours(millis),
                TimeUnit.MILLISECONDS.toMinutes(millis)
                        - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS
                        .toHours(millis)),
                TimeUnit.MILLISECONDS.toSeconds(millis)
                        - TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS
                        .toMinutes(millis)));
        System.out.println(hms);
        times.setText(hms);
    }


}

private void setQuestionView() {

    // the method which will put all things together
    txtQuestion.setText(currentQuestion.getQUESTION());
    Answer1.setText(currentQuestion.getOPT1());
    Answer2.setText(currentQuestion.getOPT2());
    Answer3.setText(currentQuestion.getOPT3());
    Answer4.setText(currentQuestion.getOPT4());

    qid++;
}


}

Answer 1

您需要播种 suffle 才能真正随机化。

通常编程语言使用固定表进行随机化。如果您不提供种子，则随机总是从表格的开头执行。当您提供种子时，该种子是表的第一个索引。

种子可以是在每次执行中都不同的任何东西。一种常见的种子是 Time.now()

要为您的 suffle 播种，您需要将种子作为第二个参数传递给 suffle 方法：

Collections.shuffle(list, new Random(Your seed));

更多信息在这里：Setting a seed to shuffle ArrayList in Java deterministically