diff --git a/project/Build.scala b/project/Build.scala
index f2e6a431..d74bcc5a 100644
--- a/project/Build.scala
+++ b/project/Build.scala
@@ -5,8 +5,8 @@ import sbtandroid._
 import sbtandroid.AndroidKeys._
 
 object App {
-  val version = "1.7.1"
-  val versionCode = 38
+  val version = "1.7.2"
+  val versionCode = 39
 }
 
 object General {
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksService.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksService.scala
index d1bc282c..3271461e 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksService.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksService.scala
@@ -197,6 +197,7 @@ class ShadowsocksService extends Service {
       // initialize timer
       val task = new TimerTask {
         def run() {
+          val pm = getSystemService(Context.POWER_SERVICE).asInstanceOf[PowerManager]
           val now = new TrafficStat(TrafficStats.getTotalTxBytes,
             TrafficStats.getTotalRxBytes, java.lang.System.currentTimeMillis())
           val txRate = ((now.tx - last.tx) / 1024 / TIMER_INTERVAL).toInt
@@ -208,7 +209,7 @@ class ShadowsocksService extends Service {
             lastTxRate = txRate
             lastRxRate = rxRate
           }
-          if (state == State.CONNECTED) {
+          if (pm.isScreenOn && state == State.CONNECTED) {
             notifyForegroundAlert(getString(R.string.forward_success),
               getString(R.string.service_status).format(txRate, rxRate), txRate + rxRate)
           }