diff --git a/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala b/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
index 6cba8d7d..74fb80ec 100644
--- a/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
+++ b/src/main/scala/com/github/shadowsocks/ServiceBoundContext.scala
@@ -8,11 +8,11 @@ import com.github.shadowsocks.utils.Action
 /**
   * @author Mygod
   */
-trait ServiceBoundContext extends Context { outer =>
+trait ServiceBoundContext extends Context {
   class ShadowsocksServiceConnection extends ServiceConnection {
     override def onServiceConnected(name: ComponentName, service: IBinder) {
+      service.linkToDeath(new ShadowsocksDeathRecipient(ServiceBoundContext.this), 0)
       bgService = IShadowsocksService.Stub.asInterface(service)
-      bgService.asBinder().linkToDeath(new ShadowsocksDeathRecipient(outer), 0)
       registerCallback
       ServiceBoundContext.this.onServiceConnected()
     }
@@ -26,18 +26,18 @@ trait ServiceBoundContext extends Context { outer =>
     }
   }
 
-  def registerCallback = if (bgService != null && callback != null && !callbackRegistered) try {
+  protected def registerCallback = if (bgService != null && callback != null && !callbackRegistered) try {
     bgService.registerCallback(callback)
     callbackRegistered = true
   } catch {
     case ignored: RemoteException => // Nothing
   }
 
-  def unregisterCallback = if (bgService != null && callback != null && callbackRegistered) try {
-    bgService.unregisterCallback(callback)
+  protected def unregisterCallback = {
+    if (bgService != null && callback != null && callbackRegistered) try bgService.unregisterCallback(callback) catch {
+      case ignored: RemoteException =>
+    }
     callbackRegistered = false
-  } catch {
-    case ignored: RemoteException => callbackRegistered = false
   }
 
   def onServiceConnected() = ()
@@ -66,16 +66,12 @@ trait ServiceBoundContext extends Context { outer =>
   }
 
   def deattachService() {
-    if (bgService != null) {
-      if (callback != null) {
-        unregisterCallback
-        callback = null
-      }
-      if (connection != null) {
-        unbindService(connection)
-        connection = null
-      }
-      bgService = null
+    unregisterCallback
+    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 bcc2b6cc..a7660d8a 100644
--- a/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
+++ b/src/main/scala/com/github/shadowsocks/Shadowsocks.scala
@@ -318,8 +318,6 @@ class Shadowsocks
     changeSwitch(checked = false)
   }
 
-  def isReady: Boolean = checkText(Key.proxy) && checkText(Key.sitekey) && bgService != null
-
   def prepareStartService() {
     ThrowableFuture {
       if (ShadowsocksApplication.isVpnEnabled) {
@@ -358,18 +356,9 @@ class Shadowsocks
 
     fab = findViewById(R.id.fab).asInstanceOf[FloatingActionButton]
     fabProgressCircle = findViewById(R.id.fabProgressCircle).asInstanceOf[FABProgressCircle]
-    fab.setOnClickListener((v: View) => {
-      serviceStarted = !serviceStarted
-      serviceStarted match {
-        case true =>
-          if (isReady)
-            prepareStartService()
-          else
-            changeSwitch(checked = false)
-        case false =>
-          serviceStop()
-      }
-    })
+    fab.setOnClickListener((v: View) => if (serviceStarted) serviceStop()
+      else if (checkText(Key.proxy) && checkText(Key.sitekey) && bgService != null) prepareStartService()
+      else changeSwitch(checked = false))
     fab.setOnLongClickListener((v: View) => {
       Utils.positionToast(Toast.makeText(this, if (serviceStarted) R.string.stop else R.string.connect,
         Toast.LENGTH_SHORT), fab, getWindow, 0, Utils.dpToPx(this, 8)).show
diff --git a/src/main/scala/com/github/shadowsocks/ShadowsocksDeathRecipient.scala b/src/main/scala/com/github/shadowsocks/ShadowsocksDeathRecipient.scala
index 97b4b519..cfaae1bd 100644
--- a/src/main/scala/com/github/shadowsocks/ShadowsocksDeathRecipient.scala
+++ b/src/main/scala/com/github/shadowsocks/ShadowsocksDeathRecipient.scala
@@ -18,8 +18,8 @@ class ShadowsocksDeathRecipient(val mContext: ServiceBoundContext)
     mContext match {
       case ss: Shadowsocks =>
         inShadowsocks(mContext) {
-          ss.unregisterCallback
-          ss.bindToService()
+          ss.deattachService
+          ss.attachService
         }
       case _ =>
     }
diff --git a/src/main/scala/com/github/shadowsocks/utils/CloseUtils.scala b/src/main/scala/com/github/shadowsocks/utils/CloseUtils.scala
index edd85aeb..cb7f9bc1 100644
--- a/src/main/scala/com/github/shadowsocks/utils/CloseUtils.scala
+++ b/src/main/scala/com/github/shadowsocks/utils/CloseUtils.scala
@@ -4,11 +4,14 @@ package com.github.shadowsocks.utils
   * @author Mygod
   */
 object CloseUtils {
+  type Closeable = {
+    def close()
+  }
   type Disconnectable = {
     def disconnect()
   }
 
-  def autoClose[A <: AutoCloseable, B](x: => A)(block: A => B): B = {
+  def autoClose[A <: Closeable, B](x: => A)(block: A => B): B = {
     var a: Option[A] = None
     try {
       a = Some(x)
diff --git a/src/main/scala/com/github/shadowsocks/utils/ProcessUtils.scala b/src/main/scala/com/github/shadowsocks/utils/ProcessUtils.scala
index 299ad09c..7ff8029c 100644
--- a/src/main/scala/com/github/shadowsocks/utils/ProcessUtils.scala
+++ b/src/main/scala/com/github/shadowsocks/utils/ProcessUtils.scala
@@ -3,41 +3,32 @@ package com.github.shadowsocks.utils
 import java.io.{BufferedReader, FileInputStream, InputStreamReader}
 
 import android.content.Context
-import com.github.shadowsocks.utils.IOUtils._
+import com.github.shadowsocks.utils.CloseUtils._
 
 /**
   * @author chentaov5@gmail.com
   */
 object ProcessUtils {
-
-  def getCurrentProcessName: String = {
-    inSafe {
-      val inputStream = new FileInputStream("/proc/self/cmdline")
-      val reader = new BufferedReader(new InputStreamReader(inputStream))
-      autoClose(reader) {
-        val sb = new StringBuilder
-        var c: Int = 0
-        while({c = reader.read(); c > 0})
-          sb.append(c.asInstanceOf[Char])
-        sb.toString()
-      }
-    } match {
-      case Some(name: String) => name
-      case None => ""
+  def getCurrentProcessName = autoClose(new FileInputStream("/proc/self/cmdline")) { inputStream =>
+    autoClose(new BufferedReader(new InputStreamReader(inputStream))) { reader =>
+      val sb = new StringBuilder
+      var c = 0
+      while ({c = reader.read(); c > 0}) sb.append(c.asInstanceOf[Char])
+      sb.toString()
     }
   }
 
-  def inShadowsocks[A](context: Context)(fun: => A): Unit = {
+  def inShadowsocks(context: Context)(fun: => Unit) {
     if (context != null && getCurrentProcessName.equals(context.getPackageName)) fun
   }
 
 
-  def inVpn[A](context: Context)(fun: => A): Unit = {
+  def inVpn(context: Context)(fun: => Unit) {
     if (context != null && getCurrentProcessName.equals(context.getPackageName + ":vpn")) fun
   }
 
 
-  def inNat[A](context: Context)(fun: => A): Unit = {
+  def inNat(context: Context)(fun: => Unit) {
     if (context != null && getCurrentProcessName.equals(context.getPackageName + ":nat")) fun
   }