diff --git a/project/Build.scala b/project/Build.scala
index 07affd9f..f2e6a431 100644
--- a/project/Build.scala
+++ b/project/Build.scala
@@ -5,8 +5,8 @@ import sbtandroid._
 import sbtandroid.AndroidKeys._
 
 object App {
-  val version = "1.7.0"
-  val versionCode = 37
+  val version = "1.7.1"
+  val versionCode = 38
 }
 
 object General {
diff --git a/src/main/res/values/strings.xml b/src/main/res/values/strings.xml
index 1d537146..bd3b82ee 100755
--- a/src/main/res/values/strings.xml
+++ b/src/main/res/values/strings.xml
@@ -40,6 +40,8 @@
   <string name="bypass_apps_summary">Enable this option to bypass selected apps</string>
   <string name="auto_connect">Auto Connect</string>
   <string name="auto_connect_summary">Enable Shadowsocks on startup</string>
+  <string name="traffic_stat">Traffic Stats</string>
+  <string name="traffic_stat_summary">Show traffic stats on notification bar</string>
 
   <!-- notification category -->
   <string name="forward_success">Shadowsocks started.</string>
diff --git a/src/main/res/xml/pref_feature.xml b/src/main/res/xml/pref_feature.xml
index 4eaff493..a7512283 100755
--- a/src/main/res/xml/pref_feature.xml
+++ b/src/main/res/xml/pref_feature.xml
@@ -28,6 +28,12 @@
       android:title="@string/proxied_apps">
     <intent android:action="com.github.shadowsocks.AppManager"/>
   </Preference>
+  <CheckBoxPreference
+      android:key="isTrafficStat"
+      android:defaultValue="true"
+      android:summary="@string/traffic_stat_summary"
+      android:title="@string/traffic_stat">
+  </CheckBoxPreference>
   <CheckBoxPreference
       android:key="isAutoConnect"
       android:summary="@string/auto_connect_summary"
diff --git a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
index 0b921540..7b9011e1 100644
--- a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
+++ b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
@@ -136,7 +136,7 @@ object Shadowsocks {
         if (pref != null) {
           val status = getActivity.getSharedPreferences(Key.status, Context.MODE_PRIVATE)
           val isRoot = status.getBoolean(Key.isRoot, false)
-          if (Seq(Key.isAutoConnect, Key.isGlobalProxy,
+          if (Seq(Key.isAutoConnect, Key.isGlobalProxy, Key.isTrafficStat,
             Key.isBypassApps, Key.proxyedApps).contains(name)) {
             pref.setEnabled(enabled && isRoot)
           } else {
@@ -506,7 +506,7 @@ class Shadowsocks
     for (name <- Shadowsocks.FEATRUE_PREFS) {
       val pref = findPreference(name)
       if (pref != null) {
-        if (Seq(Key.isAutoConnect, Key.isGlobalProxy,
+        if (Seq(Key.isAutoConnect, Key.isGlobalProxy, Key.isTrafficStat,
           Key.isBypassApps, Key.proxyedApps).contains(name)) {
           pref.setEnabled(enabled && isRoot)
         } else {
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksService.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksService.scala
index 54bc37f5..d1bc282c 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksService.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksService.scala
@@ -105,7 +105,7 @@ class ShadowsocksService extends Service {
   private var last: TrafficStat = null
   private var lastTxRate = 0
   private var lastRxRate = 0
-  private val timer = new Timer(true)
+  private var timer: Timer = null
   private val TIMER_INTERVAL = 1
 
   private def changeState(s: Int) {
@@ -193,6 +193,32 @@ class ShadowsocksService extends Service {
 
     config = Extra.get(intent)
 
+    if (config.isTrafficStat) {
+      // initialize timer
+      val task = new TimerTask {
+        def run() {
+          val now = new TrafficStat(TrafficStats.getTotalTxBytes,
+            TrafficStats.getTotalRxBytes, java.lang.System.currentTimeMillis())
+          val txRate = ((now.tx - last.tx) / 1024 / TIMER_INTERVAL).toInt
+          val rxRate = ((now.rx - last.rx) / 1024 / TIMER_INTERVAL).toInt
+          last = now
+          if (lastTxRate == txRate && lastRxRate == rxRate) {
+            return
+          } else {
+            lastTxRate = txRate
+            lastRxRate = rxRate
+          }
+          if (state == State.CONNECTED) {
+            notifyForegroundAlert(getString(R.string.forward_success),
+              getString(R.string.service_status).format(txRate, rxRate), txRate + rxRate)
+          }
+        }
+      }
+      last = new TrafficStat(TrafficStats.getTotalTxBytes,
+        TrafficStats.getTotalRxBytes, java.lang.System.currentTimeMillis())
+      timer = new Timer(true)
+      timer.schedule(task, TIMER_INTERVAL * 1000, TIMER_INTERVAL * 1000)
+    }
 
     spawn {
       killProcesses()
@@ -308,7 +334,9 @@ class ShadowsocksService extends Service {
         bitmap.getHeight - (bitmap.getHeight - bounds.height()) / 2, paint)
       builder.setLargeIcon(bitmap)
 
-      if (rate < 1000) {
+      if (rate == 0) {
+        builder.setSmallIcon(R.drawable.ic_stat_shadowsocks)
+      } else if (rate < 1000) {
         builder.setSmallIcon(R.drawable.ic_stat_speed, rate)
       } else if (rate <= 10000) {
         val mb = rate / 100 - 10 + 1000
@@ -390,38 +418,19 @@ class ShadowsocksService extends Service {
       }
     }
     registerReceiver(receiver, filter)
-
-    // initialize timer
-    val task = new TimerTask {
-      def run() {
-        val now = new TrafficStat(TrafficStats.getUidTxBytes(getApplicationInfo.uid),
-          TrafficStats.getUidRxBytes(getApplicationInfo.uid), java.lang.System.currentTimeMillis())
-        val txRate = ((now.tx - last.tx) / 1024 / TIMER_INTERVAL).toInt
-        val rxRate = ((now.rx - last.rx) / 1024 / TIMER_INTERVAL).toInt
-        last = now
-        if (lastTxRate == txRate && lastRxRate == rxRate) {
-          return
-        } else {
-          lastTxRate = txRate
-          lastRxRate = rxRate
-        }
-        if (state == State.CONNECTED) {
-          notifyForegroundAlert(getString(R.string.forward_success),
-            getString(R.string.service_status).format(txRate, rxRate), txRate + rxRate)
-        }
-      }
-    }
-    last = new TrafficStat(TrafficStats.getUidTxBytes(getApplicationInfo.uid),
-      TrafficStats.getUidRxBytes(getApplicationInfo.uid), java.lang.System.currentTimeMillis())
-    timer.schedule(task, TIMER_INTERVAL * 1000, TIMER_INTERVAL * 1000)
   }
 
   /** Called when the activity is closed. */
   override def onDestroy() {
 
+    // reset timer
+    if (timer != null) {
+      timer.cancel()
+      timer = null
+    }
+
     // clean up context
     changeState(State.STOPPED)
-    timer.cancel()
     EasyTracker.getTracker.setStartSession(false)
     EasyTracker.getTracker.sendEvent(TAG, "stop", getVersionName, 0L)
     stopForegroundCompat(1)
diff --git a/src/main/scala/com/github/shadowsocks/Utils.scala b/src/main/scala/com/github/shadowsocks/Utils.scala
index b2ab9c9a..4ec2bd14 100644
--- a/src/main/scala/com/github/shadowsocks/Utils.scala
+++ b/src/main/scala/com/github/shadowsocks/Utils.scala
@@ -104,7 +104,7 @@ object Config {
   }
 }
 
-case class Config(isGlobalProxy: Boolean, isGFWList: Boolean, isBypassApps: Boolean,
+case class Config(isGlobalProxy: Boolean, isGFWList: Boolean, isBypassApps: Boolean, isTrafficStat: Boolean,
                   var proxy: String, sitekey: String, encMethod: String, remotePort: Int,
                   localPort: Int, proxiedAppString: String)
 
@@ -121,6 +121,7 @@ object Key {
   val isGlobalProxy = "isGlobalProxy"
   val isGFWList = "isGFWList"
   val isBypassApps = "isBypassApps"
+  val isTrafficStat = "isTrafficStat"
 
   val proxy = "proxy"
   val sitekey = "sitekey"
@@ -152,6 +153,7 @@ object Extra {
     edit.putBoolean(Key.isGlobalProxy, config.isGlobalProxy)
     edit.putBoolean(Key.isGFWList, config.isGFWList)
     edit.putBoolean(Key.isBypassApps, config.isBypassApps)
+    edit.putBoolean(Key.isTrafficStat, config.isTrafficStat)
 
     edit.putString(Key.proxy, config.proxy)
     edit.putString(Key.sitekey, config.sitekey)
@@ -166,6 +168,8 @@ object Extra {
     val isGlobalProxy = intent.getBooleanExtra(Key.isGlobalProxy, false)
     val isGFWList = intent.getBooleanExtra(Key.isGFWList, false)
     val isBypassApps = intent.getBooleanExtra(Key.isBypassApps, false)
+    val isTrafficStat = intent.getBooleanExtra(Key.isTrafficStat, false)
+
     val proxy = intent.getStringExtra(Key.proxy)
     val sitekey = intent.getStringExtra(Key.sitekey)
     val encMethod = intent.getStringExtra(Key.encMethod)
@@ -173,7 +177,7 @@ object Extra {
     val localPort = intent.getIntExtra(Key.localPort, 1984)
     val proxiedString = intent.getStringExtra(Key.proxied)
 
-    new Config(isGlobalProxy, isGFWList, isBypassApps, proxy, sitekey, encMethod, remotePort,
+    new Config(isGlobalProxy, isGFWList, isBypassApps, isTrafficStat, proxy, sitekey, encMethod, remotePort,
       localPort, proxiedString)
   }
 
@@ -181,6 +185,8 @@ object Extra {
     val isGlobalProxy = settings.getBoolean(Key.isGlobalProxy, false)
     val isGFWList = settings.getBoolean(Key.isGFWList, false)
     val isBypassApps = settings.getBoolean(Key.isBypassApps, false)
+    val isTrafficStat = settings.getBoolean(Key.isTrafficStat, false)
+
     val proxy = settings.getString(Key.proxy, "127.0.0.1") match {
       case "198.199.101.152" => if (!BuildConfig.DEBUG) "ss.maxcdn.info" else "198.199.101.152"
       case s: String => s
@@ -207,6 +213,7 @@ object Extra {
     intent.putExtra(Key.isGlobalProxy, isGlobalProxy)
     intent.putExtra(Key.isGFWList, isGFWList)
     intent.putExtra(Key.isBypassApps, isBypassApps)
+    intent.putExtra(Key.isTrafficStat, isTrafficStat)
 
     intent.putExtra(Key.proxy, proxy)
     intent.putExtra(Key.sitekey, sitekey)