Java 如何修复随机数组中的此错误_Java_Arrays_Android Studio

Java 如何修复随机数组中的此错误

java arrays android-studio

Java 如何修复随机数组中的此错误,java,arrays,android-studio,Java,Arrays,Android Studio,我目前正在开发这个简单的应用程序，创建一个包含十个问题的测验，并将其随机设置。这是我到目前为止的进展，问题是随机的，这是我需要的，但问题是这些问题是重复的，我只需要它们显示一次。请帮我修复这个错误 activity_quick.xml： <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/ap

我目前正在开发这个简单的应用程序，创建一个包含十个问题的测验，并将其随机设置。这是我到目前为止的进展，问题是随机的，这是我需要的，但问题是这些问题是重复的，我只需要它们显示一次。请帮我修复这个错误

activity_quick.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    >

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="8dp"
        android:layout_marginBottom="40dp">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Score"
            android:textSize="20sp"
            android:layout_alignParentLeft="true"
            android:id="@+id/score_text"/>

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/score"
            android:layout_alignParentRight="true"
            android:text="0"
            android:textSize="20sp"/>

    </RelativeLayout>

    <TextView
        android:id="@+id/question"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="40dp"
        android:padding="80dp"
        android:text="Question"
        android:textSize="15sp" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Choice 1"
        android:padding="8dp"
        android:layout_marginBottom="24dp"
        android:id="@+id/choice1" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Choice 2"
        android:padding="8dp"
        android:layout_marginBottom="24dp"
        android:id="@+id/choice2" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Choice 3"
        android:padding="8dp"
        android:layout_marginBottom="24dp"
        android:id="@+id/choice3" />

    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Choice 4"
        android:padding="8dp"
        android:layout_marginBottom="24dp"
        android:id="@+id/choice4" />

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <Button
            android:id="@+id/backQuiz"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_marginBottom="100dp"
            android:text="Back to Table of Content"
            />
    </RelativeLayout>


</LinearLayout>```

QuizActivity.java：

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import java.util.Random;

public class QuizActivity extends AppCompatActivity {


    TextView mScoreView,mQuestionView;
    Button mButtonChoice1,mButtonChoice2,mButtonChoice3,mButtonChoice4,backQuiz;

    private QuestionsLibrary mQuestions = new QuestionsLibrary();

    private String mAnswer;
    private int mScore = 0;
    private int num = 0;
    private int mQuestionsLenght = mQuestions.mQuestions.length;

    Random r;

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

        r = new Random ();

        mScoreView = (TextView) findViewById (R.id.score);
        mQuestionView = (TextView) findViewById (R.id.question);
        mButtonChoice1 = (Button) findViewById (R.id.choice1);
        mButtonChoice2 = (Button) findViewById (R.id.choice2);
        mButtonChoice3 = (Button) findViewById (R.id.choice3);
        mButtonChoice4 = (Button) findViewById (R.id.choice4);
        backQuiz = (Button) findViewById (R.id.backQuiz);

        mScoreView.setText ("Score:" + mScore);

        updateQuestion (1+r.nextInt(mQuestionsLenght));

        mButtonChoice1.setOnClickListener (new View.OnClickListener (){
            @Override
            public void onClick(View v) {

                if (mButtonChoice1.getText () == mAnswer){
                    mScore = mScore + 1;
                    mScoreView.setText ("Score:" + mScore);
                    updateScore(mScore);
                    updateQuestion (r.nextInt (mQuestionsLenght));

                    Toast.makeText (QuizActivity.this, "Correct", Toast.LENGTH_SHORT).show ();
                }else {
                    Toast.makeText (QuizActivity.this, "Wrong", Toast.LENGTH_SHORT).show ();
                    updateQuestion (r.nextInt (mQuestionsLenght));
                }
            }
        });

        mButtonChoice2.setOnClickListener (new View.OnClickListener (){
            @Override
            public void onClick(View v) {

                if (mButtonChoice2.getText () == mAnswer){
                    mScore = mScore + 1;
                    mScoreView.setText ("Score:" + mScore);
                    updateScore(mScore);
                    updateQuestion (r.nextInt (mQuestionsLenght));

                    Toast.makeText (QuizActivity.this, "Correct", Toast.LENGTH_SHORT).show ();
                }else {
                    Toast.makeText (QuizActivity.this, "Wrong", Toast.LENGTH_SHORT).show ();
                    updateQuestion (r.nextInt (mQuestionsLenght));
                }
            }
        });

        mButtonChoice3.setOnClickListener (new View.OnClickListener (){
            @Override
            public void onClick(View v) {

                if (mButtonChoice3.getText () == mAnswer){
                    mScore = mScore + 1;
                    mScoreView.setText ("Score:" + mScore);
                    updateScore(mScore);
                    updateQuestion (r.nextInt (mQuestionsLenght));

                    Toast.makeText (QuizActivity.this, "Correct", Toast.LENGTH_SHORT).show ();
                }else {
                    Toast.makeText (QuizActivity.this, "Wrong", Toast.LENGTH_SHORT).show ();
                    updateQuestion (r.nextInt (mQuestionsLenght));
                }
            }
        });

        mButtonChoice4.setOnClickListener (new View.OnClickListener (){
            @Override
            public void onClick(View v) {

                if (mButtonChoice4.getText () == mAnswer){
                    mScore = mScore + 1;
                    mScoreView.setText ("Score:" + mScore);
                    updateScore(mScore);
                    updateQuestion (r.nextInt (mQuestionsLenght));

                    Toast.makeText (QuizActivity.this, "Correct", Toast.LENGTH_SHORT).show ();
                }else {
                    Toast.makeText (QuizActivity.this, "Wrong", Toast.LENGTH_SHORT).show ();
                    updateQuestion (r.nextInt (mQuestionsLenght));
                }
            }
        });

        backQuiz.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(QuizActivity.this, tableofcontentActivity2.class);
                startActivity(i);
            }
        });


    }

    private void updateQuestion(int num){
        mQuestionView.setText (mQuestions.getQuestion (num));
        mButtonChoice1.setText (mQuestions.getChoice1 (num));
        mButtonChoice2.setText (mQuestions.getChoice2 (num));
        mButtonChoice3.setText (mQuestions.getChoice3 (num));
        mButtonChoice4.setText (mQuestions.getChoice4 (num));

        mAnswer = mQuestions.getCorrectAnswer (num);
    }
    private void updateScore(int point) {
        mScoreView.setText ("" + mScore);
    }

急切初始化

创建一个混乱的问题列表

根据无序顺序反复使用问题

洗牌

List shuffledQuestions=IntStream.range（0，mQuestionsLenght）
.boxed（）.collect（collector.toList（））；
集合。洗牌（洗牌问题）；

用迭代索引替换random.nextInt

使用

currentIndex=0

使用

mQuestions.getQuestion（currentIndex++）而不是r.nextInt（mquestionLength）


惰性失效
维护一组seen
问题
重复生成r.nextInt
，如果它已在中查看
使用生成的问号作为查看
（添加到集合）
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import java.util.Random;

public class QuizActivity extends AppCompatActivity {


    TextView mScoreView,mQuestionView;
    Button mButtonChoice1,mButtonChoice2,mButtonChoice3,mButtonChoice4,backQuiz;

    private QuestionsLibrary mQuestions = new QuestionsLibrary();

    private String mAnswer;
    private int mScore = 0;
    private int num = 0;
    private int mQuestionsLenght = mQuestions.mQuestions.length;

    Random r;

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

        r = new Random ();

        mScoreView = (TextView) findViewById (R.id.score);
        mQuestionView = (TextView) findViewById (R.id.question);
        mButtonChoice1 = (Button) findViewById (R.id.choice1);
        mButtonChoice2 = (Button) findViewById (R.id.choice2);
        mButtonChoice3 = (Button) findViewById (R.id.choice3);
        mButtonChoice4 = (Button) findViewById (R.id.choice4);
        backQuiz = (Button) findViewById (R.id.backQuiz);

        mScoreView.setText ("Score:" + mScore);

        updateQuestion (1+r.nextInt(mQuestionsLenght));

        mButtonChoice1.setOnClickListener (new View.OnClickListener (){
            @Override
            public void onClick(View v) {

                if (mButtonChoice1.getText () == mAnswer){
                    mScore = mScore + 1;
                    mScoreView.setText ("Score:" + mScore);
                    updateScore(mScore);
                    updateQuestion (r.nextInt (mQuestionsLenght));

                    Toast.makeText (QuizActivity.this, "Correct", Toast.LENGTH_SHORT).show ();
                }else {
                    Toast.makeText (QuizActivity.this, "Wrong", Toast.LENGTH_SHORT).show ();
                    updateQuestion (r.nextInt (mQuestionsLenght));
                }
            }
        });

        mButtonChoice2.setOnClickListener (new View.OnClickListener (){
            @Override
            public void onClick(View v) {

                if (mButtonChoice2.getText () == mAnswer){
                    mScore = mScore + 1;
                    mScoreView.setText ("Score:" + mScore);
                    updateScore(mScore);
                    updateQuestion (r.nextInt (mQuestionsLenght));

                    Toast.makeText (QuizActivity.this, "Correct", Toast.LENGTH_SHORT).show ();
                }else {
                    Toast.makeText (QuizActivity.this, "Wrong", Toast.LENGTH_SHORT).show ();
                    updateQuestion (r.nextInt (mQuestionsLenght));
                }
            }
        });

        mButtonChoice3.setOnClickListener (new View.OnClickListener (){
            @Override
            public void onClick(View v) {

                if (mButtonChoice3.getText () == mAnswer){
                    mScore = mScore + 1;
                    mScoreView.setText ("Score:" + mScore);
                    updateScore(mScore);
                    updateQuestion (r.nextInt (mQuestionsLenght));

                    Toast.makeText (QuizActivity.this, "Correct", Toast.LENGTH_SHORT).show ();
                }else {
                    Toast.makeText (QuizActivity.this, "Wrong", Toast.LENGTH_SHORT).show ();
                    updateQuestion (r.nextInt (mQuestionsLenght));
                }
            }
        });

        mButtonChoice4.setOnClickListener (new View.OnClickListener (){
            @Override
            public void onClick(View v) {

                if (mButtonChoice4.getText () == mAnswer){
                    mScore = mScore + 1;
                    mScoreView.setText ("Score:" + mScore);
                    updateScore(mScore);
                    updateQuestion (r.nextInt (mQuestionsLenght));

                    Toast.makeText (QuizActivity.this, "Correct", Toast.LENGTH_SHORT).show ();
                }else {
                    Toast.makeText (QuizActivity.this, "Wrong", Toast.LENGTH_SHORT).show ();
                    updateQuestion (r.nextInt (mQuestionsLenght));
                }
            }
        });

        backQuiz.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent i = new Intent(QuizActivity.this, tableofcontentActivity2.class);
                startActivity(i);
            }
        });


    }

    private void updateQuestion(int num){
        mQuestionView.setText (mQuestions.getQuestion (num));
        mButtonChoice1.setText (mQuestions.getChoice1 (num));
        mButtonChoice2.setText (mQuestions.getChoice2 (num));
        mButtonChoice3.setText (mQuestions.getChoice3 (num));
        mButtonChoice4.setText (mQuestions.getChoice4 (num));

        mAnswer = mQuestions.getCorrectAnswer (num);
    }
    private void updateScore(int point) {
        mScoreView.setText ("" + mScore);
    }