NathanWalker
diff --git a/tests/app/ui/animation/animation-tests.ts b/tests/app/ui/animation/animation-tests.ts
@@ -57,7 +57,6 @@ export function test_AnimatingProperties(done) {
 export function test_PlayRejectsWhenAlreadyPlayingAnimation(done) {
     let label = prepareTest();
 
-    // >> animation-play
     var animation = label.createAnimation({ translate: { x: 100, y: 100 }, duration: 5 });
 
     animation.play();
@@ -70,18 +69,14 @@ export function test_PlayRejectsWhenAlreadyPlayingAnimation(done) {
             done();
         }
     });
-    // << animation-play
 }
 
-export function test_CancelIgnoredWhenNotPlayingAnimation(done) {
+export function test_CancelIgnoredWhenNotPlayingAnimation() {
     let label = prepareTest();
 
-    // >> animation-cancel-ignore
     var animation = label.createAnimation({ translate: { x: 100, y: 100 }, duration: 5 });
     animation.cancel(); // should not throw
     TKUnit.assert(!animation.isPlaying, "animation.isPlaying should be falsey since it was never played.");
-    done();
-    // << animation-cancel-ignore
 }
 
 export function test_CancellingAnimation(done) {

diff --git a/tns-core-modules/ui/animation/animation-common.ts b/tns-core-modules/ui/animation/animation-common.ts
@@ -10,9 +10,9 @@ import { View } from "../core/view";
 
 // Types.
 import { Color } from "../../color";
-import { isEnabled as traceEnabled, write as traceWrite, categories as traceCategories } from "../../trace";
+import { isEnabled as traceEnabled, write as traceWrite, categories as traceCategories, messageType as traceType } from "../../trace";
 
-export { Color, traceEnabled, traceWrite, traceCategories };
+export { Color, traceEnabled, traceWrite, traceCategories, traceType };
 export { AnimationPromise } from ".";
 
 export module Properties {
@@ -84,17 +84,16 @@ export abstract class AnimationBase implements AnimationBaseDefinition {
 
     abstract _resolveAnimationCurve(curve: any): any;
 
-    public play(): AnimationPromiseDefinition {
-        if (this.isPlaying) {
-            const reason = "Animation is already playing.";
-            if (traceEnabled()) {
-                traceWrite(reason, traceCategories.Animation, 2);
-            }
-            return <AnimationPromiseDefinition>new Promise<void>((resolve, reject) => {
-                reject(reason);
-            });
-        }
+    protected _rejectAlreadyPlaying(): AnimationPromiseDefinition{
+        const reason = "Animation is already playing.";
+        traceWrite(reason, traceCategories.Animation, traceType.warn);
+
+        return <AnimationPromiseDefinition>new Promise<void>((resolve, reject) => {
+            reject(reason);
+        });
+    }
 
+    public play(): AnimationPromiseDefinition {
         // We have to actually create a "Promise" due to a bug in the v8 engine and decedent promises
         // We just cast it to a animationPromise so that all the rest of the code works fine
         var animationFinishedPromise = <AnimationPromiseDefinition>new Promise<void>((resolve, reject) => {
@@ -129,11 +128,7 @@ export abstract class AnimationBase implements AnimationBaseDefinition {
     }
 
     public cancel(): void {
-        if (!this.isPlaying) {
-            if (traceEnabled()) {
-                traceWrite("Animation is not currently playing.", traceCategories.Animation, 2);
-            }
-        }
+        // Implemented in platform specific files
     }
 
     public get isPlaying(): boolean {

diff --git a/tns-core-modules/ui/animation/animation.android.ts b/tns-core-modules/ui/animation/animation.android.ts
@@ -2,7 +2,7 @@
 import { AnimationDefinition } from ".";
 import { View } from "../core/view";
 
-import { AnimationBase, Properties, PropertyAnimation, CubicBezierAnimationCurve, AnimationPromise, Color, traceWrite, traceEnabled, traceCategories } from "./animation-common";
+import { AnimationBase, Properties, PropertyAnimation, CubicBezierAnimationCurve, AnimationPromise, Color, traceWrite, traceEnabled, traceCategories, traceType } from "./animation-common";
 import {
     opacityProperty, backgroundColorProperty, rotateProperty,
     translateXProperty, translateYProperty, scaleXProperty, scaleYProperty
@@ -135,6 +135,10 @@ export class Animation extends AnimationBase {
     }
 
     public play(): AnimationPromise {
+        if (this.isPlaying) {
+            return this._rejectAlreadyPlaying();
+        }
+
         let animationFinishedPromise = super.play();
 
         this._animators = new Array<android.animation.Animator>();
@@ -170,10 +174,13 @@ export class Animation extends AnimationBase {
     }
 
     public cancel(): void {
-        super.cancel();
-        if (traceEnabled()) {
-            traceWrite("Cancelling AnimatorSet.", traceCategories.Animation);
+        if (!this.isPlaying) {
+            traceWrite("Animation is not currently playing.", traceCategories.Animation, traceType.warn);
+            return;
         }
+
+        traceWrite("Cancelling AnimatorSet.", traceCategories.Animation);
+
         this._animatorSet.cancel();
     }
 
@@ -301,7 +308,7 @@ export class Animation extends AnimationBase {
                     } else {
                         propertyAnimation.target.style[backgroundColorProperty.keyframe] = originalValue1;
                     }
-                    
+
                     if (propertyAnimation.target.nativeViewProtected && propertyAnimation.target[backgroundColorProperty.setNative]) {
                         propertyAnimation.target[backgroundColorProperty.setNative](propertyAnimation.target.style.backgroundColor);
                     }
@@ -414,7 +421,7 @@ export class Animation extends AnimationBase {
                     } else {
                         propertyAnimation.target.style[rotateProperty.keyframe] = originalValue1;
                     }
-                    
+
                     if (propertyAnimation.target.nativeViewProtected) {
                         propertyAnimation.target[rotateProperty.setNative](propertyAnimation.target.style.rotate);
                     }

diff --git a/tns-core-modules/ui/animation/animation.ios.ts b/tns-core-modules/ui/animation/animation.ios.ts
@@ -1,7 +1,7 @@
 import { AnimationDefinition } from ".";
 import { View } from "../core/view";
 
-import { AnimationBase, Properties, PropertyAnimation, CubicBezierAnimationCurve, AnimationPromise, traceWrite, traceEnabled, traceCategories } from "./animation-common";
+import { AnimationBase, Properties, PropertyAnimation, CubicBezierAnimationCurve, AnimationPromise, traceWrite, traceEnabled, traceCategories, traceType } from "./animation-common";
 import {
     opacityProperty, backgroundColorProperty, rotateProperty,
     translateXProperty, translateYProperty, scaleXProperty, scaleYProperty
@@ -210,6 +210,10 @@ export class Animation extends AnimationBase {
     }
 
     public play(): AnimationPromise {
+        if (this.isPlaying) {
+            return this._rejectAlreadyPlaying();
+        }
+
         let animationFinishedPromise = super.play();
         this._finishedAnimations = 0;
         this._cancelledAnimations = 0;
@@ -218,7 +222,10 @@ export class Animation extends AnimationBase {
     }
 
     public cancel(): void {
-        super.cancel();
+        if (!this.isPlaying) {
+            traceWrite("Animation is not currently playing.", traceCategories.Animation, traceType.warn);
+            return;
+        }
 
         let i = 0;
         let length = this._mergedPropertyAnimations.length;

diff --git a/tns-core-modules/ui/animation/keyframe-animation.ts b/tns-core-modules/ui/animation/keyframe-animation.ts
@@ -12,7 +12,7 @@ import { View, Color } from "../core/view";
 
 import { AnimationCurve } from "../enums";
 
-import { isEnabled as traceEnabled, write as traceWrite, categories as traceCategories } from "../../trace";
+import { isEnabled as traceEnabled, write as traceWrite, categories as traceCategories, messageType as traceType } from "../../trace";
 
 // Types.
 import { unsetValue } from "../core/properties";
@@ -145,28 +145,29 @@ export class KeyframeAnimation implements KeyframeAnimationDefinition {
     }
 
     public cancel() {
-        if (this._isPlaying) {
-            this._isPlaying = false;
-            for (let i = this._nativeAnimations.length - 1; i >= 0; i--) {
-                let animation = this._nativeAnimations[i];
-                if (animation.isPlaying) {
-                    animation.cancel();
-                }
-            }
-            if (this._nativeAnimations.length > 0) {
-                let animation = this._nativeAnimations[0];
-                this._resetAnimationValues(this._target, animation);
+        if (!this.isPlaying) {
+            traceWrite("Keyframe animation is already playing.", traceCategories.Animation, traceType.warn);
+            return;
+        }
+
+        this._isPlaying = false;
+        for (let i = this._nativeAnimations.length - 1; i >= 0; i--) {
+            let animation = this._nativeAnimations[i];
+            if (animation.isPlaying) {
+                animation.cancel();
             }
-            this._rejectAnimationFinishedPromise();
         }
+        if (this._nativeAnimations.length > 0) {
+            let animation = this._nativeAnimations[0];
+            this._resetAnimationValues(this._target, animation);
+        }
+        this._rejectAnimationFinishedPromise();
     }
 
     public play(view: View): Promise<void> {
         if (this._isPlaying) {
             const reason = "Keyframe animation is already playing.";
-            if (traceEnabled()) {
-                traceWrite(reason, traceCategories.Animation, 2);
-            }
+            traceWrite(reason, traceCategories.Animation, traceType.warn);
             return new Promise<void>((resolve, reject) => {
                 reject(reason);
             });