嘿伙计们，我正在开发一个测验，其中存储了 50 个问题，然后我希望只显示 10 个问题..问题是随机显示的..但我的问题是应该在测验中显示 10 个问题.请帮助我...非常感谢您的帮助..
public class Question1 extends Activity {
Intent menu = null;
BufferedReader bReader = null;
static JSONArray quesList = null;
static int index = 50;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.question10);
Thread thread = new Thread() {
public void run() {
try {
Thread.sleep(1 * 1000);
finish();
loadQuestions();
Intent intent = new Intent(Question1.this,
Question2.class);
Question1.this.startActivity(intent);
} catch (Exception e) {
}
}
};
thread.start();
}
private void loadQuestions() throws Exception {
try {
InputStream questions = this.getBaseContext().getResources()
.openRawResource(R.raw.questions);
bReader = new BufferedReader(new InputStreamReader(questions));
StringBuilder quesString = new StringBuilder();
String aJsonLine = null;
while ((aJsonLine = bReader.readLine()) != null) {
quesString.append(aJsonLine);
}
Log.d(this.getClass().toString(), quesString.toString());
JSONObject quesObj = new JSONObject(quesString.toString());
quesList = quesObj.getJSONArray("Questions");
Log.d(this.getClass().getName(),
"Num Questions " + quesList.length());
} catch (Exception e) {
} finally {
try {
bReader.close();
} catch (Exception e) {
Log.e("", e.getMessage().toString(), e.getCause());
}
}
}
public static JSONArray getQuesList()throws JSONException{
Random rnd = new Random();
for (int i = quesList.length() - 1; i >= 0; i--)
{
int j = rnd.nextInt(i + 1);
// Simple swap
Object object = quesList.get(j);
quesList.put(j, quesList.get(i));
quesList.put(i, object);
}
return quesList;
}
最佳答案
由于您希望每个测验都有动态的 10 个问题，您可以使用 Collections.shuffle(YourList) 来打乱 ArrayList并从该随机列表中取出前 10 个。
但是，当您拥有 JSONArray 时，您必须迭代它并准备 ArrayList，这样您就可以使用 shuffle() .
更新:
引用ogzd的回答，这样你就会有问题作为List<JsonObject> ，现在你只需调用我上面提到的 shuffle 方法:
Collections.shuffle(questions);
现在，它会打乱问题列表，因此您必须从中复制或取出前 10 项。
关于java - 如何在android中使用json数组限制问题的长度？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/15018917/