diff --git a/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala b/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
index e6cbbeaf..c304f559 100644
--- a/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
+++ b/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
@@ -67,11 +67,13 @@ trait ServiceBoundContext extends Context {
         } catch {
           case ignored: RemoteException => // Nothing
         }
+        callback = null
       }
       if (connection != null) {
         unbindService(connection)
         connection = null
       }
+      bgService = null
     }
   }
 }
diff --git a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
index 9b652522..895c487f 100644
--- a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
+++ b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
@@ -157,6 +157,13 @@ class Shadowsocks
 
   // Services
   var currentServiceName = classOf[ShadowsocksNatService].getName
+  private val callback = new IShadowsocksServiceCallback.Stub {
+    def stateChanged(state: Int, msg: String) = onStateChanged(state, msg)
+    def trafficUpdated(txRate: String, rxRate: String, txTotal: String, rxTotal: String) =
+      Shadowsocks.this.trafficUpdated(txRate, rxRate, txTotal, rxTotal)
+  }
+
+  def attachService: Unit = attachService(callback)
 
   override def onServiceConnected() {
     // Update the UI
@@ -377,16 +384,7 @@ class Shadowsocks
     })
 
     // Bind to the service
-    handler.post(() => {
-      attachService(new IShadowsocksServiceCallback.Stub {
-        override def stateChanged(state: Int, msg: String) {
-          onStateChanged(state, msg)
-        }
-        override def trafficUpdated(txRate: String, rxRate: String, txTotal: String, rxTotal: String) {
-          Shadowsocks.this.trafficUpdated(txRate, rxRate, txTotal, rxTotal)
-        }
-      })
-    })
+    handler.post(() => attachService)
   }
 
   def reloadProfile() {
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala
index 684fc0ed..b63c7d81 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksSettings.scala
@@ -67,7 +67,7 @@ class ShadowsocksSettings extends PreferenceFragment with OnSharedPreferenceChan
     })
   }
 
-  override def onResume = {
+  override def onResume {
     super.onResume
     isProxyApps.setChecked(ShadowsocksApplication.settings.getBoolean(Key.isProxyApps, false))  // update
   }
@@ -75,9 +75,8 @@ class ShadowsocksSettings extends PreferenceFragment with OnSharedPreferenceChan
   def onSharedPreferenceChanged(sharedPreferences: SharedPreferences, key: String) = key match {
     case Key.isNAT => if (ShadowsocksApplication.isRoot && activity != null) {
       activity.handler.post(() => {
-        val intent = activity.getIntent
-        activity.finish()
-        startActivity(intent)
+        activity.deattachService
+        activity.attachService
       })
     }
     case _ =>