Merge pull request #4 from shu223/2_background-support

background support

Pulsator.podspec

@@ -1,12 +1,12 @@
 Pod::Spec.new do |s|
   s.name             = "Pulsator"
-  s.version          = "0.1.0"
+  s.version          = "0.1.1"
   s.summary          = "Pulse animation for iOS."
   s.homepage         = "https://github.com/shu223/Pulsator"
   s.screenshots      = "https://github.com/shu223/Pulsator/blob/master/demo.gif?raw=true"
   s.license          = 'MIT'
   s.author           = { "shu223" => "[email protected]" }
-  s.source           = { :git => "https://github.com/shu223/Pulsator.git", :tag => "0.1.0" }
+  s.source           = { :git => "https://github.com/shu223/Pulsator.git", :tag => "0.1.1" }
   s.social_media_url = 'https://twitter.com/shu223'
 
   s.platform     = :ios, '8.0'

Pulsator/Pulsator.swift

@@ -24,7 +24,7 @@ public class Pulsator: CAReplicatorLayer {
             pulse.backgroundColor = backgroundColor
             let oldAlpha = alpha
             alpha = CGColorGetAlpha(backgroundColor)
-            if animationGroup != nil && alpha != oldAlpha {
+            if alpha != oldAlpha {
                 recreate()
             }
         }
@@ -83,9 +83,7 @@ public class Pulsator: CAReplicatorLayer {
     /// The value of this property should be ranging from @c 0 to @c 1 (exclusive).
     public var keyTimeForHalfOpacity: Float = 0.2 {
         didSet {
-            if animationGroup != nil {
-                recreate()
-            }
+            recreate()
         }
     }
 
@@ -179,6 +177,7 @@ public class Pulsator: CAReplicatorLayer {
     // MARK: - Internal Methods
 
     internal func recreate() {
+        guard animationGroup != nil else { return }        // Not need to be recreated.
         stop()
         let when = dispatch_time(DISPATCH_TIME_NOW, Int64(0.2 * double_t(NSEC_PER_SEC)))
         dispatch_after(when, dispatch_get_main_queue()) { () -> Void in