diff --git a/MotionAnimation/MotionAnimator.swift b/MotionAnimation/MotionAnimator.swift
index 9419037..15e746f 100644
--- a/MotionAnimation/MotionAnimator.swift
+++ b/MotionAnimation/MotionAnimator.swift
@@ -33,7 +33,7 @@ open class MotionAnimator: NSObject {
     super.init()
   }
 
-  func update() {
+  @objc func update() {
     _removeAllPendingStopAnimations()
 
     let duration = CGFloat(displayLink.duration)
diff --git a/MotionAnimation/Types.swift b/MotionAnimation/Types.swift
index ffa4869..10ca8e6 100644
--- a/MotionAnimation/Types.swift
+++ b/MotionAnimation/Types.swift
@@ -81,7 +81,11 @@ extension UIColor:MotionAnimatableProperty{
     return self.init(red: values[0], green: values[1], blue: values[2], alpha: values[3])
   }
   public func toCGFloatValues(_ values: inout [CGFloat]) {
-    self.getRed(&values[0], green: &values[1], blue: &values[2], alpha: &values[3])
+    var r = values[0]
+    var g : CGFloat = values[1]
+    var b : CGFloat = values[2]
+    var a : CGFloat = values[3]
+    self.getRed(&r, green: &g, blue: &b, alpha: &a)
   }
 }
 
diff --git a/MotionAnimationExample.xcodeproj/project.pbxproj b/MotionAnimationExample.xcodeproj/project.pbxproj
index 393f866..9d7e562 100644
--- a/MotionAnimationExample.xcodeproj/project.pbxproj
+++ b/MotionAnimationExample.xcodeproj/project.pbxproj
@@ -152,14 +152,14 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0720;
-				LastUpgradeCheck = 0800;
+				LastUpgradeCheck = 0900;
 				ORGANIZATIONNAME = lkzhao;
 				TargetAttributes = {
 					A3D92B211C6803C000C34FBD = {
 						CreatedOnToolsVersion = 7.2;
 						DevelopmentTeam = 4VSEW78TKT;
 						DevelopmentTeamName = "Yi Lun Zhao";
-						LastSwiftMigration = 0800;
+						LastSwiftMigration = 0900;
 					};
 				};
 			};
@@ -237,14 +237,20 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
@@ -284,14 +290,20 @@
 				CLANG_CXX_LIBRARY = "libc++";
 				CLANG_ENABLE_MODULES = YES;
 				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
 				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
 				CLANG_WARN_SUSPICIOUS_MOVE = YES;
 				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
@@ -324,7 +336,8 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.lkzhao.MotionAnimation;
 				PRODUCT_NAME = MotionAnimationExample;
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -337,7 +350,8 @@
 				PRODUCT_BUNDLE_IDENTIFIER = com.lkzhao.MotionAnimation;
 				PRODUCT_NAME = MotionAnimationExample;
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};
diff --git a/MotionAnimationExample/ListViewController.swift b/MotionAnimationExample/ListViewController.swift
index 9036809..62604da 100644
--- a/MotionAnimationExample/ListViewController.swift
+++ b/MotionAnimationExample/ListViewController.swift
@@ -47,7 +47,7 @@ class ListViewController: ExampleBaseViewController {
     listItems.first?.m_animate("center", to: CGPoint(x: view.center.x, y: 150), stiffness: 200, damping:15, threshold:1)
   }
   
-  func pan(_ gr:LZPanGestureRecognizer){
+  @objc func pan(_ gr:LZPanGestureRecognizer){
     switch gr.state{
     case .began, .changed:
       // move the item under touch
diff --git a/MotionAnimationExample/SquareViewController.swift b/MotionAnimationExample/SquareViewController.swift
index 5347ad4..3e2fdce 100644
--- a/MotionAnimationExample/SquareViewController.swift
+++ b/MotionAnimationExample/SquareViewController.swift
@@ -54,7 +54,7 @@ class SquareViewController: ExampleBaseViewController {
   }
   
   var isBig = false
-  func doubleTap(_ gr:UITapGestureRecognizer){
+  @objc func doubleTap(_ gr:UITapGestureRecognizer){
     let newSize = isBig ? CGSize(width: 150, height: 150) : CGSize(width: 200, height: 200)
     let newColor = isBig ? UIColor.white : UIColor.black
     isBig = !isBig
@@ -62,11 +62,11 @@ class SquareViewController: ExampleBaseViewController {
     square.m_animate("bounds", to: CGRect(origin: CGPoint.zero, size: newSize), stiffness:200, damping:10)
   }
   
-  func tap(_ gr:UITapGestureRecognizer){
+  @objc func tap(_ gr:UITapGestureRecognizer){
     square.m_animate("center", to: gr.location(in: view), stiffness:200, damping:10)
   }
 
-  func pan(_ gr:LZPanGestureRecognizer){
+  @objc func pan(_ gr:LZPanGestureRecognizer){
     // high stiffness -> high acceleration (will help it stay under touch)
     square.m_animate("center", to: gr.translatedViewCenterPoint, stiffness:500, damping:25)
   }