兼容移动端听写题

src/views/exercise_questions/preview/WordDictationPreview.vue

@@ -170,7 +170,10 @@ export default {
           item.pinyin_arr.push(obj);
         });
         if (this.isJudgingRightWrong) {
-          item.imgArr = this.answer.answer_list[index].strokes_content_list;
+          item.imgArr =
+            this.answer.answer_list[index] && this.answer.answer_list[index].strokes_content_list
+              ? this.answer.answer_list[index].strokes_content_list
+              : arr;
         } else {
           item.imgArr = arr;
         }