160818

modify arr2string return nil when arr is empty.

RedAnt ERP Mobile/common/RAUtils.m

@@ -1106,7 +1106,8 @@
 }
 +(NSString*) arr2string:(NSArray *) arr separator:(NSString*)separator trim:(bool) btrim
 {
-    
+    if(arr.count==0)
+        return nil;
     NSMutableArray * marr = [arr mutableCopy];
     
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