修复 发送消息问题

src/views/teacher/student_list/SendMessage.vue

@@ -47,6 +47,7 @@ export default {
     },
 
     send() {
+      if (this.message.length === 0) return this.$message.warning('消息内容不能为空');
       this.$emit('sendMessage', this.message);
     }
   }

src/views/teacher/student_list/index.vue

@@ -163,9 +163,10 @@ export default {
         type: this.type,
         student_id: this.student_id
       }).then(({ message_count }) => {
-        loading.close();
         this.visible = false;
         this.$message.success(`已成功发送${message_count}条消息`);
+      }).finally(() => {
+        loading.close();
       });
     },