diff --git a/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/value/ResStringValue.java b/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/value/ResStringValue.java
index a7cabc59..94f568c8 100644
--- a/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/value/ResStringValue.java
+++ b/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/value/ResStringValue.java
@@ -65,6 +65,9 @@ public class ResStringValue extends ResScalarValue {
     }
 
     private String checkIfStringIsNumeric(String val) {
+        if (val == null || val.isEmpty()) {
+            return val;
+        }
         return allDigits.matcher(val).matches() ? "\\ " + val : val;
     }