Fix ScreenSaver problem.

src/utilities/Locker.cpp

@@ -37,7 +37,11 @@ void Locker::setIsEnable(bool aIsEnable)
     mIsEnable = aIsEnable;
     if (!mIsEnable)
     {
-        mScreenTimer->stop();
+        stop();
+    }
+    else
+    {
+        start();
     }
 }
 
@@ -58,12 +62,18 @@ void Locker::setTimer(int aInterval)
 {
     mCounter = aInterval;
     mScreenTimer->stop();
-    mScreenTimer->start(mCounter);
+    if (mIsEnable)
+    {
+        mScreenTimer->start(mCounter);
+    }
 }
 void Locker::refreshTimer()
 {
-    mScreenTimer->stop();
-    mScreenTimer->start(mCounter);
+    if (mIsEnable)
+    {
+        mScreenTimer->stop();
+        mScreenTimer->start(mCounter);
+    }
 }
 
 void Locker::stop()