Merge pull request #2002 from NativeScript/jasssonpet/lazy-snapshot

Evaluate lazily Android specific global values

CrossPlatformModules.csproj

@@ -1038,6 +1038,8 @@
     </TypeScriptCompile>
     <TypeScriptCompile Include="utils\debug.d.ts" />
     <TypeScriptCompile Include="utils\debug.ts" />
+    <TypeScriptCompile Include="utils\lazy.d.ts" />
+    <TypeScriptCompile Include="utils\lazy.ts" />
     <TypeScriptCompile Include="utils\module-merge.ts" />
     <TypeScriptCompile Include="utils\utils.android.ts">
       <DependentUpon>utils.d.ts</DependentUpon>

tsconfig.json

@@ -703,6 +703,8 @@
         "ui/web-view/web-view.ios.ts",
         "utils/debug.d.ts",
         "utils/debug.ts",
+        "utils/lazy.d.ts",
+        "utils/lazy.ts",
         "utils/module-merge.ts",
         "utils/number-utils.ts",
         "utils/types.d.ts",

ui/animation/animation.android.ts

@@ -6,6 +6,7 @@ import trace = require("trace");
 import types = require("utils/types");
 import enums = require("ui/enums");
 import styleModule = require("ui/styling/style");
+import lazy from "utils/lazy";
 
 global.moduleMerge(common, exports);
 
@@ -359,28 +360,28 @@ export class Animation extends common.Animation implements definition.Animation
     }
 }
 
-let easeIn = new android.view.animation.AccelerateInterpolator(1);
+let easeIn = lazy(() => new android.view.animation.AccelerateInterpolator(1));
-let easeOut = new android.view.animation.DecelerateInterpolator(1);
+let easeOut = lazy(() => new android.view.animation.DecelerateInterpolator(1));
-let easeInOut = new android.view.animation.AccelerateDecelerateInterpolator();
+let easeInOut = lazy(() => new android.view.animation.AccelerateDecelerateInterpolator());
-let linear = new android.view.animation.LinearInterpolator();
+let linear = lazy(() => new android.view.animation.LinearInterpolator());
-let bounce = new android.view.animation.BounceInterpolator();
+let bounce = lazy(() => new android.view.animation.BounceInterpolator());
 export function _resolveAnimationCurve(curve: any): any {
     switch (curve) {
         case enums.AnimationCurve.easeIn:
             trace.write("Animation curve resolved to android.view.animation.AccelerateInterpolator(1).", trace.categories.Animation);
-            return easeIn;
+            return easeIn();
         case enums.AnimationCurve.easeOut:
             trace.write("Animation curve resolved to android.view.animation.DecelerateInterpolator(1).", trace.categories.Animation);
-            return easeOut;
+            return easeOut();
         case enums.AnimationCurve.easeInOut:
             trace.write("Animation curve resolved to android.view.animation.AccelerateDecelerateInterpolator().", trace.categories.Animation);
-            return easeInOut;
+            return easeInOut();
         case enums.AnimationCurve.linear:
             trace.write("Animation curve resolved to android.view.animation.LinearInterpolator().", trace.categories.Animation);
-            return linear;
+            return linear();
         case enums.AnimationCurve.spring:
             trace.write("Animation curve resolved to android.view.animation.BounceInterpolator().", trace.categories.Animation);
-            return bounce;
+            return bounce();
         case enums.AnimationCurve.ease:
             return (<any>android).support.v4.view.animation.PathInterpolatorCompat.create(0.25, 0.1, 0.25, 1.0);
         default:

ui/transition/slide-transition.android.ts

@@ -1,8 +1,9 @@
 import transition = require("ui/transition");
 import platform = require("platform");
+import lazy from "utils/lazy";
 
-var screenWidth = platform.screen.mainScreen.widthPixels;
+var screenWidth = lazy(() => platform.screen.mainScreen.widthPixels);
-var screenHeight = platform.screen.mainScreen.heightPixels;
+var screenHeight = lazy(() => platform.screen.mainScreen.heightPixels);
 
 export class SlideTransition extends transition.Transition {
     private _direction: string;
@@ -18,80 +19,80 @@ export class SlideTransition extends transition.Transition {
             case "left":
                 switch (transitionType) {
                     case transition.AndroidTransitionType.enter:
-                        translationValues[0] = screenWidth;
+                        translationValues[0] = screenWidth();
                         translationValues[1] = 0;
                         break;
                     case transition.AndroidTransitionType.exit:
                         translationValues[0] = 0;
-                        translationValues[1] = -screenWidth;
+                        translationValues[1] = -screenWidth();
                         break;
                     case transition.AndroidTransitionType.popEnter:
-                        translationValues[0] = -screenWidth;
+                        translationValues[0] = -screenWidth();
                         translationValues[1] = 0;
                         break;
                     case transition.AndroidTransitionType.popExit:
                         translationValues[0] = 0;
-                        translationValues[1] = screenWidth;
+                        translationValues[1] = screenWidth();
                         break;
                 }
                 break;
             case "right":
                 switch (transitionType) {
                     case transition.AndroidTransitionType.enter:
-                        translationValues[0] = -screenWidth;
+                        translationValues[0] = -screenWidth();
                         translationValues[1] = 0;
                         break;
                     case transition.AndroidTransitionType.exit:
                         translationValues[0] = 0;
-                        translationValues[1] = screenWidth;
+                        translationValues[1] = screenWidth();
                         break;
                     case transition.AndroidTransitionType.popEnter:
-                        translationValues[0] = screenWidth;
+                        translationValues[0] = screenWidth();
                         translationValues[1] = 0;
                         break;
                     case transition.AndroidTransitionType.popExit:
                         translationValues[0] = 0;
-                        translationValues[1] = -screenWidth;
+                        translationValues[1] = -screenWidth();
                         break;
                 }
                 break;
             case "top":
                 switch (transitionType) {
                     case transition.AndroidTransitionType.enter:
-                        translationValues[0] = screenHeight;
+                        translationValues[0] = screenHeight();
                         translationValues[1] = 0;
                         break;
                     case transition.AndroidTransitionType.exit:
                         translationValues[0] = 0;
-                        translationValues[1] = -screenHeight;
+                        translationValues[1] = -screenHeight();
                         break;
                     case transition.AndroidTransitionType.popEnter:
-                        translationValues[0] = -screenHeight;
+                        translationValues[0] = -screenHeight();
                         translationValues[1] = 0;
                         break;
                     case transition.AndroidTransitionType.popExit:
                         translationValues[0] = 0;
-                        translationValues[1] = screenHeight;
+                        translationValues[1] = screenHeight();
                         break;
                 }
                 break;
             case "bottom":
                 switch (transitionType) {
                     case transition.AndroidTransitionType.enter:
-                        translationValues[0] = -screenHeight;
+                        translationValues[0] = -screenHeight();
                         translationValues[1] = 0;
                         break;
                     case transition.AndroidTransitionType.exit:
                         translationValues[0] = 0;
-                        translationValues[1] = screenHeight;
+                        translationValues[1] = screenHeight();
                         break;
                     case transition.AndroidTransitionType.popEnter:
-                        translationValues[0] = screenHeight;
+                        translationValues[0] = screenHeight();
                         translationValues[1] = 0;
                         break;
                     case transition.AndroidTransitionType.popExit:
                         translationValues[0] = 0;
-                        translationValues[1] = -screenHeight;
+                        translationValues[1] = -screenHeight();
                         break;
                 }
                 break;

ui/transition/transition.android.ts

@@ -5,9 +5,10 @@ import pageModule = require("ui/page");
 import * as animationModule from "ui/animation";
 import types = require("utils/types");
 import trace = require("trace");
+import lazy from "utils/lazy";
 
-var _sdkVersion = parseInt(platform.device.sdkVersion);
+var _sdkVersion = lazy(() => parseInt(platform.device.sdkVersion));
-var _defaultInterpolator = new android.view.animation.AccelerateDecelerateInterpolator();
+var _defaultInterpolator = lazy(() => new android.view.animation.AccelerateDecelerateInterpolator());
 
 interface CompleteOptions {
     isBack: boolean;
@@ -40,7 +41,7 @@ export function _clearBackwardTransitions(fragment: any): void {
         expandedFragment.enterPopExitTransition = undefined;
     }
     
-    if (_sdkVersion >= 21) {
+    if (_sdkVersion() >= 21) {
         var enterTransition = (<any>fragment).getEnterTransition();
         if (enterTransition) {
             trace.write(`Cleared Enter ${enterTransition.getClass().getSimpleName()} transition for ${fragment.getTag()}`, trace.categories.Transition);
@@ -61,7 +62,7 @@ export function _clearForwardTransitions(fragment: any): void {
         expandedFragment.exitPopEnterTransition = undefined;
     }
 
-    if (_sdkVersion >= 21) {
+    if (_sdkVersion() >= 21) {
         var exitTransition = (<any>fragment).getExitTransition();
         if (exitTransition) {
             trace.write(`Cleared Exit ${exitTransition.getClass().getSimpleName()} transition for ${fragment.getTag()}`, trace.categories.Transition);
@@ -81,7 +82,7 @@ export function _setAndroidFragmentTransitions(navigationTransition: frameModule
         name = navigationTransition.name.toLowerCase();
     }
     
-    var useLollipopTransition = name && (name.indexOf("slide") === 0 || name === "fade" || name === "explode") && _sdkVersion >= 21;
+    var useLollipopTransition = name && (name.indexOf("slide") === 0 || name === "fade" || name === "explode") && _sdkVersion() >= 21;
     if (useLollipopTransition) {
         // setEnterTransition: Enter
         // setExitTransition: Exit
@@ -229,7 +230,7 @@ function _setUpNativeTransition(navigationTransition: frameModule.NavigationTran
         nativeTransition.setInterpolator(interpolator);
     }
     else {
-        nativeTransition.setInterpolator(_defaultInterpolator);
+        nativeTransition.setInterpolator(_defaultInterpolator());
     }
 }
 
@@ -241,7 +242,7 @@ export function _onFragmentShown(fragment: any, isBack: boolean): void {
         trace.write(`${fragment.getTag() } has been shown when going ${isBack ? "back" : "forward"}, but there is ${transitionType} ${relevantTransition}. Will complete page addition when transition ends.`, trace.categories.Transition);
         expandedFragment.completePageAdditionWhenTransitionEnds = { isBack: isBack };
     }
-    else if (_sdkVersion >= 21) {
+    else if (_sdkVersion() >= 21) {
         var nativeTransition = isBack ? (<any>fragment).getReenterTransition() : (<any>fragment).getEnterTransition();
         if (nativeTransition) {
             trace.write(`${fragment.getTag() } has been shown when going ${isBack ? "back" : "forward"}, but there is ${transitionType} ${nativeTransition.getClass().getSimpleName()} transition. Will complete page addition when transition ends.`, trace.categories.Transition);
@@ -262,7 +263,7 @@ export function _onFragmentHidden(fragment: any, isBack: boolean, destroyed: boo
         trace.write(`${fragment.getTag()} has been hidden when going ${isBack ? "back" : "forward"}, but there is ${transitionType} ${relevantTransition}. Will complete page removal when transition ends.`, trace.categories.Transition);
         expandedFragment.completePageRemovalWhenTransitionEnds = { isBack: isBack };
     }
-    else if (_sdkVersion >= 21) {
+    else if (_sdkVersion() >= 21) {
         var nativeTransition = isBack ? (<any>fragment).getReturnTransition() : (<any>fragment).getExitTransition();
         if (nativeTransition) {
             trace.write(`${fragment.getTag()} has been hidden when going ${isBack ? "back" : "forward"}, but there is ${transitionType} ${nativeTransition.getClass().getSimpleName()} transition. Will complete page removal when transition ends.`, trace.categories.Transition);
@@ -422,7 +423,7 @@ export class Transition implements definition.Transition {
             this._interpolator = animation._resolveAnimationCurve(curve);
         }
         else {
-            this._interpolator = _defaultInterpolator;
+            this._interpolator = _defaultInterpolator();
         }
         this._id = transitionId++;
     }

utils/lazy.d.ts

@@ -0,0 +1,8 @@
+declare module "utils/lazy" {
+    /**
+     * A function that evaluates the action only once.
+     * @param action The action to be evaluated to get the result.
+     * Returns the evaluated result.
+     */
+    export default function lazy<T>(action: () => T): () => T;
+}

utils/lazy.ts

@@ -0,0 +1,4 @@
+export default function lazy<T>(action: () => T): () => T {
+    let _value: T;
+    return () => _value || (_value = action());
+}