我目前正在进行国旗测验。设置编码，以便玩家每次都可以通过按下4个answerButtons中的1个来接收玩家必须猜测的新随机标记。玩家是否猜错了下一个标志应该加载并且相同的国家标志不应该重复，直到所有标志都已显示或者玩家已经失去了一生（= 5个生命）并且游戏重新开始（这部分不是已编程）。但事实并非如此。偶尔，由于一些奇怪的原因，同样的旗帜重新出现，无法弄清楚如何完全阻止这种情况。
问题： 在显示所有标志之前，我该如何防止重新出现相同的标志？
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的文件：
<?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>
答案 0 :(得分：1)
保留一个开头为空的整数列表。显示标志后，将其位置保存到此列表，并在显示标志之前，检查此列表。如果标志位置在列表内部，则它已经显示，请选择另一个。如果list size = flag list size，那么你已经显示了所有标志。
答案 1 :(得分：0)
我能想到的最好的方法是在加载国家/地区之后随机排序国家列表，然后按照列表的方式进行操作。
答案 2 :(得分：0)
在getRandomIndex方法循环中为您的表达式添加否定（exclemation mark）。因为它现在循环直到随机数为 IN excludeList。
} while (!excludeList.contains(number));
在您搜索随机整数时，excludeList中只有一个整数，因此它搜索一些随机int，直到找到一个与整数excludeList匹配的整数。所以每次都会得到相同的整数值。