修复问卷做过有答案不显示的问题

teachinteraction/src/main/java-que/com/offcn/teachinteraction/questionnaire/mvp/ui/activity/StuQuestionnaireMainActivity.java

@@ -720,9 +720,12 @@ public class  StuQuestionnaireMainActivity extends BaseActivity<StuQuestionnaire
     @Override
     public QuestionnaireQuestionAnswerBean getAnswerResult(int questionId) {
         try {
+            if(idAnswerMap==null){
                 idAnswerMap = new ArrayMap<>(questionList.size());
+            }else{
                 return idAnswerMap.get(questionId);
-        }catch (NullPointerException e){
+            }
+        } catch (NullPointerException e) {
 
         }
        return null;