增加 保养子表状态为null提醒

app/src/main/java/com/example/jingyuan_mes/entity/device/MaintainDetail.java

@@ -64,9 +64,14 @@ public class MaintainDetail extends BaseObservable {
     }
 
     public String getButtonText() {
-        if ( maintStatus !=3) {
-            return "开始保养";
+        try {
+            if ( maintStatus !=3) {
+                return "开始保养";
+            }
+        }catch (Exception exception){
+            return "子表maintStatus报错";
         }
+
         // return "完成保养";
         return "查看保养";