diff --git a/.idea/modules.xml b/.idea/modules.xml
index cf4f13d..a822a05 100644
--- a/.idea/modules.xml
+++ b/.idea/modules.xml
@@ -2,12 +2,9 @@
 <project version="4">
   <component name="ProjectModuleManager">
     <modules>
-      <module fileurl="file://$PROJECT_DIR$/BTDemo.iml" filepath="$PROJECT_DIR$/BTDemo.iml" />
       <module fileurl="file://D:\Project\ble-android-demo\BTDemo.iml" filepath="D:\Project\ble-android-demo\BTDemo.iml" />
       <module fileurl="file://$PROJECT_DIR$/app/app.iml" filepath="$PROJECT_DIR$/app/app.iml" />
-      <module fileurl="file://D:\Project\ble-android-demo\app\app.iml" filepath="D:\Project\ble-android-demo\app\app.iml" />
       <module fileurl="file://$PROJECT_DIR$/ble-android-demo.iml" filepath="$PROJECT_DIR$/ble-android-demo.iml" />
-      <module fileurl="file://D:\Project\ble-android-demo\ble-android-demo.iml" filepath="D:\Project\ble-android-demo\ble-android-demo.iml" />
     </modules>
   </component>
 </project>
\ No newline at end of file
diff --git a/app/src/main/java/xyz/mtfos/btdemo/PrinterBle.java b/app/src/main/java/xyz/mtfos/btdemo/PrinterBle.java
index 93f5cba..9719e9d 100644
--- a/app/src/main/java/xyz/mtfos/btdemo/PrinterBle.java
+++ b/app/src/main/java/xyz/mtfos/btdemo/PrinterBle.java
@@ -312,7 +312,7 @@ public class PrinterBle {
     }
 
     private void sendData(byte[] data) {
-        if (data == null || data.length < 1 || data.length > 20) return;
+        if (data == null || data.length < 1 || data.length > 20 || printerCharacteristic == null) return;
 
         boolean setVal = printerCharacteristic.setValue(data);
         boolean sendVal = mBtGatt.writeCharacteristic(printerCharacteristic);