android - 如何防止相同的图像重复自身？

Question

我目前正在做国旗测验。设置编码，以便玩家每次都会收到一个新的随机标志，并且玩家必须通过按 4 个回答按钮中的 1 个来猜测。玩家是否猜测下一个旗帜是否应该加载并且同一个国家的旗帜不应该重复出现，直到所有旗帜都被显示或者玩家已经失去了所有的生命(= 5 条生命)并且游戏重新开始(这部分不是尚未编程)。然而，事实并非如此。时不时地，由于某些奇怪的原因再次出现相同的标志，无法弄清楚如何完全防止这种情况。

问题:在显示所有标志之前，我该如何防止再次出现相同的标志？

.

JAVA 文件:

public class EasyActivity extends AppCompatActivity {

    private final static String Folder = "Easy";
    private ImageView flagImageView;
    private List<String> countries;
    private List<Button> suggestionsBtns;
    private int currentCountryIndex;
    private final static Random random = new Random ();
    TextView currentScoreTextView;
    TextView currentLivesTextView;
    TextView answerTextViewEasy;
    Animation shakeAnimation;

    int correctAnswer = 0;
    int currentScore = 1;
    int currentLives = 5;

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

        answerTextViewEasy = (TextView) findViewById(R.id.answerTextViewEasy);
        currentScoreTextView = (TextView) findViewById(R.id.currentScoreEasy);
        currentLivesTextView = (TextView) findViewById(R.id.currentLivesEasy);

        loadCountries ();
        initUi ();

        try {
            randomize ();
        } catch (Exception e) {
            e.printStackTrace ();
        }
    }//onCreate ends here


    private void randomize () throws Exception {
        currentCountryIndex = random.nextInt (countries.size ());

        InputStream is = getAssets ().open (Folder + File.separator + countries.get (currentCountryIndex));
        flagImageView.setImageBitmap (BitmapFactory.decodeStream (is));
        is.close ();

        int randomCountry1 = getRandomIndex (countries.size (), currentCountryIndex);
        int randomCountry2 = getRandomIndex (countries.size (), currentCountryIndex, randomCountry1);
        int randomCountry3 = getRandomIndex (countries.size (), currentCountryIndex, randomCountry1, randomCountry2);

        int randomCorrectCountryPos = getRandomIndex (4);
        int randomCountry1Pos     = getRandomIndex (4, randomCorrectCountryPos);
        int randomCountry2Pos     = getRandomIndex (4, randomCorrectCountryPos, randomCountry1Pos);
        int randomCountry3Pos     = getRandomIndex (4, randomCorrectCountryPos, randomCountry1Pos, randomCountry2Pos);

        suggestionsBtns.get (randomCorrectCountryPos).setText (countries.get (currentCountryIndex).split (".png")[0]);
        suggestionsBtns.get (randomCountry1Pos).setText (countries.get (randomCountry1).split (".png")[0]);
        suggestionsBtns.get (randomCountry2Pos).setText (countries.get (randomCountry2).split (".png")[0]);
        suggestionsBtns.get (randomCountry3Pos).setText (countries.get (randomCountry3).split (".png")[0]);

    }//randomisze ends here


    private int getRandomIndex (int size, Integer... excludes) {
        List<Integer> excludeList = Arrays.asList (excludes);
        int number;
        do {
            number = random.nextInt (size);
        } while (excludeList.contains (number));

        return number;

    }//getRandomIndex ends here


    private void loadCountries () {
        countries = new ArrayList<> ();
        try {
            String [] list = getAssets().list (Folder);
            countries = Arrays.asList (list);
        } catch (IOException e) {
            e.printStackTrace ();
        }

    }//loadCountries ends here


    private void checkCorrectness (String chosenCountry) {
        if (chosenCountry.equals (countries.get (currentCountryIndex).split (".png")[0])) {
            for (int i = 1; i <= correctAnswer; i++) {
                currentScore = currentScore + i;
            }//for-loop ends here
            correctAnswer++;
            currentScore++;
            String score = Integer.toString(currentScore);
            currentScoreTextView.setText(score);
            String answerText = chosenCountry;
            answerTextViewEasy.setText(answerText + "!");
            answerTextViewEasy.setTextColor(ContextCompat.getColor(getApplicationContext(), R.color.correct_answer));
        }else{
            currentLives--;
            String lives = Integer.toString(currentLives);
            currentLivesTextView.setText(lives);
            answerTextViewEasy.setText("Incorrect!");
            answerTextViewEasy.setTextColor(ContextCompat.getColor(getApplicationContext(), R.color.incorrect_answer));
            shakeAnimation = AnimationUtils.loadAnimation(getApplicationContext(), R.anim.incorrect_shake);
            shakeAnimation.setRepeatCount(3);
            flagImageView.startAnimation(shakeAnimation);
        }//else ends here
            try {
                randomize ();
            } catch (Exception e) {
                e.printStackTrace ();
            }//try-loop ends here
    }//checkCorrectness ends here


    private void initUi () {
        flagImageView = (ImageView)findViewById (R.id.flagImageViewEasy);

        suggestionsBtns = new ArrayList<>();
        suggestionsBtns.add ((Button)findViewById (R.id.answerButton1Easy));
        suggestionsBtns.add ((Button)findViewById (R.id.answerButton3Easy));
        suggestionsBtns.add ((Button)findViewById (R.id.answerButton2Easy));
        suggestionsBtns.add ((Button)findViewById (R.id.answerButton4Easy));

        for (final Button btn : suggestionsBtns) {
            btn.setOnClickListener (new View.OnClickListener () {

                @Override
                public void onClick (View v) {
                    checkCorrectness (btn.getText ().toString ());
                }//onClick ends here
            });
        }//for-loop ends here
    }//initUi ends here

}//EasyActivity ends here

XML 文件:

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/quizLinearLayoutEasy"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="16dp"
    android:paddingLeft="16dp"
    android:paddingRight="16dp"
    android:paddingTop="16dp"
    tools:context="com.example.android.kingofflags.EasyActivity">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:layout_marginLeft="5dp"
        android:layout_marginStart="5dp"
        android:orientation="horizontal">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/currentScoreText"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="2dp"
                android:layout_marginRight="2dp"
                android:text="@string/current_score"
                android:textColor="@android:color/black"
                android:textSize="20sp" />

            <TextView
                android:id="@+id/currentScoreEasy"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/current_score_0"
                android:textColor="@android:color/holo_red_dark"
                android:textSize="20sp" />

        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="205dp"
            android:layout_marginStart="205dp"
            android:orientation="horizontal">

            <TextView
                android:id="@+id/lives"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginEnd="2dp"
                android:layout_marginRight="2dp"
                android:gravity="center"
                android:text="@string/lives"
                android:textColor="@android:color/black"
                android:textSize="20sp" />

            <TextView
                android:id="@+id/currentLivesEasy"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="@string/lives_5"
                android:textColor="@android:color/holo_red_dark"
                android:textSize="20sp" />

        </LinearLayout>
    </LinearLayout>

    <ImageView
        android:id="@+id/flagImageViewEasy"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_gravity="center"
        android:layout_marginBottom="@dimen/spacing"
        android:layout_marginLeft="@dimen/activity_horizontal_margin"
        android:layout_marginRight="@dimen/activity_horizontal_margin"
        android:layout_marginTop="5dp"
        android:layout_weight="1"
        android:adjustViewBounds="true"
        android:contentDescription="@string/image_description"
        android:scaleType="fitCenter" />

    <TextView
        android:id="@+id/guessCountryTextViewEasy"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginBottom="8dp"
        android:layout_marginTop="10dp"
        android:text="@string/guess_country"
        android:textColor="#4c4c4c"
        android:textSize="20sp" />

    <LinearLayout
        android:id="@+id/row1LinearLayoutEasy"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

    </LinearLayout>

    <LinearLayout
        android:id="@+id/row2LinearLayoutEasy"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

    </LinearLayout>

    <LinearLayout
        android:id="@+id/row3LinearLayoutEasy"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="5dp"
        android:orientation="horizontal">

        <Button
            android:id="@+id/answerButton1Easy"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_marginEnd="5dp"
            android:layout_marginRight="5dp"
            android:layout_weight="1"
            android:background="@color/colorAccent"
            android:lines="2"
            android:text="New Button"
            android:textAllCaps="false"
            android:textColor="@color/button_text_color"
            android:textStyle="bold" />

        <Button
            android:id="@+id/answerButton2Easy"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:background="@color/colorAccent"
            android:lines="2"
            android:text="New Button"
            android:textAllCaps="false"
            android:textColor="@color/button_text_color"
            android:textStyle="bold" />
    </LinearLayout>

    <LinearLayout
        android:id="@+id/row4LinearLayoutEasy"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="10dp"
        android:orientation="horizontal">

        <Button
            android:id="@+id/answerButton3Easy"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_marginEnd="5dp"
            android:layout_marginRight="5dp"
            android:layout_weight="1"
            android:background="@color/colorAccent"
            android:lines="2"
            android:text="New Button"
            android:textAllCaps="false"
            android:textColor="@color/button_text_color"
            android:textStyle="bold" />

        <Button
            android:id="@+id/answerButton4Easy"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:background="@color/colorAccent"
            android:lines="2"
            android:text="New Button"
            android:textAllCaps="false"
            android:textColor="@color/button_text_color"
            android:textStyle="bold" />
    </LinearLayout>

    <TextView
        android:id="@+id/answerTextViewEasy"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|center_horizontal"
        android:gravity="center_horizontal"
        android:textSize="36sp"
        android:textStyle="bold" />

</LinearLayout>

Answer 1

保留一个开头为空的整数列表。显示标志时，将其位置保存到此列表中，并在显示标志之前检查此列表内部。如果标记位置在列表内部，则已显示，请选择另一个。如果列表大小 = 标志列表大小，那么您已经显示了所有标志。