修改查看练习结果详情内容展示逻辑

src/views/targetImprove/practice/practiceResults/practiceDetail.vue

@@ -21,8 +21,16 @@
                 </div>
                 <div class="desc">
                     该知识点练习前您的得分率是<span class="scoring_average bold">{{localPracticeDetail.frontRate === '-' ? localPracticeDetail.frontRate : localPracticeDetail.frontRate + '%'}}</span>
-                    ，练习后您的得分率是<span class="scoring_average bold">{{ [3,4].includes(localPracticeDetail.exerciseStatus) ? localPracticeDetail.afterRate + '%' : '-'}}</span>
-                    <span v-if="[3,4].includes(localPracticeDetail.exerciseStatus)">
+                    ，练习后您的得分率是<span class="scoring_average bold">{{ [3,4].includes(localPracticeDetail.exerciseStatus)
+                                                                               && localPracticeDetail.afterRate !== null 
+                                                                               && localPracticeDetail.afterRate !== '-'
+                                                                            ? localPracticeDetail.afterRate + '%' 
+                                                                            : '-'
+                                                                        }}</span>
+                    <span v-if="[3,4].includes(localPracticeDetail.exerciseStatus)
+                                  && localPracticeDetail.afterRate !== null 
+                                  && localPracticeDetail.afterRate !== '-' 
+                                  && localPracticeDetail.frontRate !== '-'">
                         ，经过专项练习该知识点得分率
                         <span v-if="Number(localPracticeDetail.afterRate) === Number(localPracticeDetail.frontRate)" class="bold">保持稳定</span>
                         <span v-else :class="['bold',Number(localPracticeDetail.afterRate) > Number(localPracticeDetail.frontRate) ? 'up_light' : 'down_light']">{{Number(localPracticeDetail.afterRate) > Number(localPracticeDetail.frontRate) ? '提升了'  : '下降了' }}{{Math.abs(localPracticeDetail.difference)}}%</span>