fix(animations): change throw -> trace to avoid unnecessary app crash (#5475)

* fix(animations): change throw -> trace to avoid unnecessary app crash

Fixes major cause of crashes/bugs in production apps using animation.

* Fix fix animation throw (#1)

* chore(tests): Cleanup code snippets comments

* refactor(animations): Plat-specific cancel and play methods refactored

tests/app/ui/animation/animation-tests.ts

@@ -54,6 +54,31 @@ export function test_AnimatingProperties(done) {
     // << animation-properties
 }
 
+export function test_PlayRejectsWhenAlreadyPlayingAnimation(done) {
+    let label = prepareTest();
+
+    var animation = label.createAnimation({ translate: { x: 100, y: 100 }, duration: 5 });
+
+    animation.play();
+    animation.play().then(() => {
+        // should never get here
+        throw new Error("Already playing.");
+    }, (e) => {
+        TKUnit.assert(animation.isPlaying === true, "animation.isPlaying should be true since it's currently playing.");
+        if (e === "Animation is already playing.") {
+            done();
+        }
+    });
+}
+
+export function test_CancelIgnoredWhenNotPlayingAnimation() {
+    let label = prepareTest();
+
+    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.");
+}
+
 export function test_CancellingAnimation(done) {
     let label = prepareTest();
 

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 {
@@ -84,11 +84,16 @@ export abstract class AnimationBase implements AnimationBaseDefinition {
 
     abstract _resolveAnimationCurve(curve: any): any;
 
-    public play(): AnimationPromiseDefinition {
-        if (this.isPlaying) {
-            throw new Error("Animation is already playing.");
+    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) => {
@@ -123,9 +128,7 @@ export abstract class AnimationBase implements AnimationBaseDefinition {
     }
 
     public cancel(): void {
-        if (!this.isPlaying) {
-            throw new Error("Animation is not currently playing.");
-        }
+        // Implemented in platform specific files
     }
 
     public get isPlaying(): boolean {

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();
     }
 

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;

tns-core-modules/ui/animation/keyframe-animation.ts

@@ -12,6 +12,8 @@ import { View, Color } from "../core/view";
 
 import { AnimationCurve } from "../enums";
 
+import { isEnabled as traceEnabled, write as traceWrite, categories as traceCategories, messageType as traceType } from "../../trace";
+
 // Types.
 import { unsetValue } from "../core/properties";
 import { Animation } from "./animation";
@@ -143,7 +145,11 @@ export class KeyframeAnimation implements KeyframeAnimationDefinition {
     }
 
     public cancel() {
-        if (this._isPlaying) {
+        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];
@@ -157,11 +163,14 @@ export class KeyframeAnimation implements KeyframeAnimationDefinition {
         }
         this._rejectAnimationFinishedPromise();
     }
-    }
 
     public play(view: View): Promise<void> {
         if (this._isPlaying) {
-            throw new Error("Animation is already playing.");
+            const reason = "Keyframe animation is already playing.";
+            traceWrite(reason, traceCategories.Animation, traceType.warn);
+            return new Promise<void>((resolve, reject) => {
+                reject(reason);
+            });
         }
 
         let animationFinishedPromise = new Promise<void>((resolve, reject) => {