我正在创建一个Android项目，一个测验应用程序
当我尝试随机复制id时，我不知道如何解决这个问题 我需要我的程序生成一个没有任何重复的随机数
她的代码活动
package com.example.testing;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Random;
import java.util.Timer;
import java.util.concurrent.TimeUnit;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Typeface;
import android.media.MediaPlayer;
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;
public class QuestionActivity extends Activity{
ArrayList<Question> quesList;
int score = 0;
int qid = 0;
int lives = 5;
Question currentQ;
TextView txtQuestion, times, scored, livess;
Button button1, button2, button3;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
QuizHelper db = new QuizHelper(this); // my question bank class
quesList = db.getAllQuestions();
Random random = new Random();// this will fetch all quetonall questions
currentQ = quesList.get( random.nextInt(quesList.size())); // 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
button1 = (Button) findViewById(R.id.button1);
button2 = (Button) findViewById(R.id.button2);
button3 = (Button) findViewById(R.id.button3);
livess = (TextView) findViewById(R.id.livess);
// the textview in which 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("00:02:00");
// A timer of 60 seconds to play for, with an interval of 1 second (1000 milliseconds)
CounterClass timer = new CounterClass(60000, 1000);
timer.start();
// button click listeners
button1.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(button1.getText().toString());
}
});
button2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
getAnswer(button2.getText().toString());
}
});
button3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
getAnswer(button3.getText().toString());
}
});
}
public void getAnswer(String AnswerString) {
if (currentQ.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(lives > 1){
lives--;
livess.setText("Lives: " + lives);
}
else {
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();
}
{
}
if (qid < 20) {
// if questions are not over then do this
Random random = new Random();
currentQ = quesList.get( random.nextInt(quesList.size()));
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.GINGERBREAD)
@SuppressLint("NewApi")
public class CounterClass extends CountDownTimer {
public CounterClass(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
// TODO Auto-generated constructor stub
}
@Override
public void onFinish() {
times.setText("Time is up");
Intent intent = new Intent(QuestionActivity.this,
Result_Activity_TimesUp.class);
Bundle b = new Bundle();
b.putInt("score", score); // Your score
intent.putExtras(b); // Put your score to your next
startActivity(intent);
finish();
}
@Override
public void onTick(long millisUntilFinished) {
// TODO Auto-generated method stub
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(currentQ.getQUESTION());
button1.setText(currentQ.getOPTA());
button2.setText(currentQ.getOPTB());
button3.setText(currentQ.getOPTC());
qid++;
}
}
继承我的数据库
package com.example.testing;
import java.util.ArrayList;
import java.util.List;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class QuizHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 3;
// Database Name
private static final String DATABASE_NAME = "mathsone";
// 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_OPTA = "opta"; // option a
private static final String KEY_OPTB = "optb"; // option b
private static final String KEY_OPTC = "optc"; // option c
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_OPTA + " TEXT, "
+ KEY_OPTB + " TEXT, " + KEY_OPTC + " TEXT)";
db.execSQL(sql);
addQuestion();
// db.close();
}
private void addQuestion() {
Question q1 = new Question("1. 5+2 = ?", "7", "8", "6", "7");
this.addQuestion(q1);
Question q2 = new Question("2. 2+18 = ?", "18", "19", "20", "20");
this.addQuestion(q2);
Question q3 = new Question("3. 10-3 = ?", "6", "7", "8", "7");
this.addQuestion(q3);
Question q4 = new Question("4. 5+7 = ?", "12", "13", "14", "12");
this.addQuestion(q4);
Question q5 = new Question("5. 3-1 = ?", "1", "3", "2", "2");
this.addQuestion(q5);
Question q6 = new Question("6. 0+1 = ?", "1", "0", "10", "1");
this.addQuestion(q6);
Question q7 = new Question("7. 9-9 = ?", "0", "9", "1", "0");
this.addQuestion(q7);
Question q8 = new Question("8. 3+6 = ?", "8", "7", "9", "9");
this.addQuestion(q8);
Question q9 = new Question("9. 1+5 = ?", "6", "7", "5", "6");
this.addQuestion(q9);
Question q10 = new Question("10. 7-5 = ?", "3", "2", "6", "2");
this.addQuestion(q10);
Question q11 = new Question("11. 7-2 = ?", "7", "6", "5", "5");
this.addQuestion(q11);
Question q12 = new Question("12. 3+5 = ?", "8", "7", "5", "8");
this.addQuestion(q12);
Question q13 = new Question("13. 0+6 = ?", "7", "6", "5", "6");
this.addQuestion(q13);
Question q14 = new Question("14. 12-10 = ?", "1", "2", "3", "2");
this.addQuestion(q14);
Question q15 = new Question("15. 12+2 = ?", "14", "15", "16", "14");
this.addQuestion(q15);
Question q16 = new Question("16. 2-1 = ?", "2", "1", "0", "1");
this.addQuestion(q16);
Question q17 = new Question("17. 6-6 = ?", "6", "12", "0", "0");
this.addQuestion(q17);
Question q18 = new Question("18. 5-1 = q?", "4", "3", "2", "4");
this.addQuestion(q18);
Question q19 = new Question("19. 4+2 = 19?", "6", "7", "5", "6");
this.addQuestion(q19);
Question q20 = new Question("20. 5+1 = ?", "6", "7", "5", "6");
this.addQuestion(q20);
Question q21 = new Question("5-4 = ?", "5", "4", "1", "1");
this.addQuestion(q21);
// 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_OPTA, quest.getOPTA());
values.put(KEY_OPTB, quest.getOPTB());
values.put(KEY_OPTC, quest.getOPTC());
// Inserting Row
dbase.insert(TABLE_QUEST, null, values);
}
public ArrayList<Question> getAllQuestions() {
ArrayList<Question> quesList = 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.setOPTA(cursor.getString(3));
quest.setOPTB(cursor.getString(4));
quest.setOPTC(cursor.getString(5));
quesList.add(quest);
} while (cursor.moveToNext());
}
// return quest list
return quesList;
}
}
答案 0 :(得分：2)
初始化一个具有原始问题对象的凹痕的数组。例如使用0和19之间的数字初始化数组。
然后，当你得到一个随机数时，在indecies数组中使用该值并将其删除。
当你得到下一个随机数时，得到0到18之间的随机数，依此类推。这样你就不应该关心复制，你总会有一个新问题。
<强> OnCreate中：
ArrayList<Question> toSelectFrom = new ArrayList<Question>();
toSelectFrom.addAll(quesList);
<强>随机
Random random = new Random();
currentQ = toSelectFrom.get(random.nextInt(toSelectFrom.size()));
toSelectFrom.remove(toSelectFrom.indexOf(currentQ));
在这里，我将问题对象放在数组中以从中选择而不是使用indecies。同样的东西。
package com.example.testing;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Random;
import java.util.Timer;
import java.util.concurrent.TimeUnit;
import android.annotation.SuppressLint;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Typeface;
import android.media.MediaPlayer;
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;
public class QuestionActivity extends Activity{
ArrayList<Question> quesList;
ArrayList<Question> toSelectFrom; // <--- HERE
int score = 0;
int qid = 0;
int lives = 5;
Question currentQ;
TextView txtQuestion, times, scored, livess;
Button button1, button2, button3;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
QuizHelper db = new QuizHelper(this); // my question bank class
quesList = db.getAllQuestions();
toSelectFrom = new ArrayList<Question>(); // <--- HERE
toSelectFrom.addAll(quesList); // <--- HERE
Random random = new Random();// this will fetch all quetonall questions
currentQ = toSelectFrom.get( random.nextInt(toSelectFrom.size())); // the current question <-- edited here too.
toSelectFrom.remove(toSelectFrom.indexOf(currentQ)); // <--- HERE
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
button1 = (Button) findViewById(R.id.button1);
button2 = (Button) findViewById(R.id.button2);
button3 = (Button) findViewById(R.id.button3);
livess = (TextView) findViewById(R.id.livess);
// the textview in which 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("00:02:00");
// A timer of 60 seconds to play for, with an interval of 1 second (1000 milliseconds)
CounterClass timer = new CounterClass(60000, 1000);
timer.start();
// button click listeners
button1.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(button1.getText().toString());
}
});
button2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
getAnswer(button2.getText().toString());
}
});
button3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
getAnswer(button3.getText().toString());
}
});
}
public void getAnswer(String AnswerString) {
if (currentQ.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(lives > 1){
lives--;
livess.setText("Lives: " + lives);
}
else {
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();
}
{
}
if (qid < 20) {
// if questions are not over then do this
Random random = new Random();
currentQ = toSelectFrom.get(random.nextInt(toSelectFrom.size())); // <<--- HERE
toSelectFrom.remove(toSelectFrom.indexOf(currentQ)); // <<--- AND HERE
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.GINGERBREAD)
@SuppressLint("NewApi")
public class CounterClass extends CountDownTimer {
public CounterClass(long millisInFuture, long countDownInterval) {
super(millisInFuture, countDownInterval);
// TODO Auto-generated constructor stub
}
@Override
public void onFinish() {
times.setText("Time is up");
Intent intent = new Intent(QuestionActivity.this,
Result_Activity_TimesUp.class);
Bundle b = new Bundle();
b.putInt("score", score); // Your score
intent.putExtras(b); // Put your score to your next
startActivity(intent);
finish();
}
@Override
public void onTick(long millisUntilFinished) {
// TODO Auto-generated method stub
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(currentQ.getQUESTION());
button1.setText(currentQ.getOPTA());
button2.setText(currentQ.getOPTB());
button3.setText(currentQ.getOPTC());
qid++;
}
}
答案 1 :(得分：-1)
编辑：
private final Random mRandom = new Random();
在某处填充您的列表：
List<Integer> values = new ArrayList<>(20);
for (int i = 0; i < values; ++i) {
values.add(i);
}
返回一个值：
private int getNextRandom(List<Integer> list) {
int index = mRandom.nextInt(list.size());
int value = list.remove(index);
return value;
}