fix(nav): swipe to go back gesture

- smoother by debouncing touch events (reduces bank)
- dynamic animation duration
- intelligent behavior based in the position, speed and direccion of the swipe (sharing logic with sliding item)

fixes ionic-team#8919
fixes ionic-team#8958
fixes ionic-team#7934

src/animations/animation.ts

@@ -861,9 +861,32 @@ export class Animation {
    * Start the animation with a user controlled progress.
    */
   progressStart() {
+    // ensure all past transition end events have been cleared
+    this._clearAsync();
+
+    // fire off all the "before" function that have DOM READS in them
+    // elements will be in the DOM, however visibily hidden
+    // so we can read their dimensions if need be
+    // ******** DOM READ ****************
+    this._beforeReadFn();
+
+    // fire off all the "before" function that have DOM WRITES in them
+    // ******** DOM WRITE ****************
+    this._beforeWriteFn();
+
+    // ******** DOM WRITE ****************
+    this._progressStart();
+  }
+
+  /**
+   * @private
+   * DOM WRITE
+   * RECURSION
+   */
+  _progressStart() {
     for (var i = 0; i < this._cL; i++) {
       // ******** DOM WRITE ****************
-      this._c[i].progressStart();
+      this._c[i]._progressStart();
     }
 
     // ******** DOM WRITE ****************
@@ -907,13 +930,14 @@ export class Animation {
   /**
    * End the progress animation.
    */
-  progressEnd(shouldComplete: boolean, currentStepValue: number) {
+  progressEnd(shouldComplete: boolean, currentStepValue: number, maxDelta: number = 0) {
     console.debug('Animation, progressEnd, shouldComplete', shouldComplete, 'currentStepValue', currentStepValue);
 
     this._isAsync = (currentStepValue > 0.05 && currentStepValue < 0.95);
 
-    const dur = 64;
     const stepValue = shouldComplete ? 1 : 0;
+    const factor = Math.max(Math.abs(currentStepValue - stepValue), 0.5) * 2;
+    const dur = 64 + factor * maxDelta;
 
     this._progressEnd(shouldComplete, stepValue, dur, this._isAsync);
 
@@ -922,7 +946,7 @@ export class Animation {
       // set the async TRANSITION END event
       // and run onFinishes when the transition ends
       // ******** DOM WRITE ****************
-      this._asyncEnd(dur, true);
+      this._asyncEnd(dur, shouldComplete);
 
       // this animation has a duration so we need another RAF
       // for the CSS TRANSITION properties to kick in

src/components/app/app.ts

@@ -71,7 +71,7 @@ export class App {
     // listen for hardware back button events
     // register this back button action with a default priority
     _platform.registerBackButtonAction(this.navPop.bind(this));
-    this._canDisableScroll = _config.get('canDisableScroll', true);
+    this._canDisableScroll = _config.get('canDisableScroll', false);
   }
 
   /**

src/components/item/item-sliding.ts

@@ -2,7 +2,7 @@ import { ChangeDetectionStrategy, Component, ContentChildren, ContentChild, Dire
 
 import { CSS, nativeRaf, nativeTimeout, clearNativeTimeout } from '../../util/dom';
 import { Item } from './item';
-import { isPresent, assert } from '../../util/util';
+import { isPresent, swipeShouldReset, assert } from '../../util/util';
 import { List } from '../list/list';
 
 const SWIPE_MARGIN = 30;
@@ -320,10 +320,10 @@ export class ItemSliding {
 
     // Check if the drag didn't clear the buttons mid-point
     // and we aren't moving fast enough to swipe open
-    let isCloseDirection = (this._openAmount > 0) === !(velocity < 0);
+    let isResetDirection = (this._openAmount > 0) === !(velocity < 0);
     let isMovingFast = Math.abs(velocity) > 0.3;
     let isOnCloseZone = Math.abs(this._openAmount) < Math.abs(restingPoint / 2);
-    if (shouldClose(isCloseDirection, isMovingFast, isOnCloseZone)) {
+    if (swipeShouldReset(isResetDirection, isMovingFast, isOnCloseZone)) {
       restingPoint = 0;
     }
 
@@ -463,22 +463,3 @@ export class ItemSliding {
     this._renderer.setElementClass(this._elementRef.nativeElement, cssClass, shouldAdd);
   }
 }
-
-function shouldClose(isCloseDirection: boolean, isMovingFast: boolean, isOnCloseZone: boolean): boolean {
-  // The logic required to know when the sliding item should close (openAmount=0)
-  // depends on three booleans (isCloseDirection, isMovingFast, isOnCloseZone)
-  // and it ended up being too complicated to be written manually without errors
-  // so the truth table is attached below: (0=false, 1=true)
-  // isCloseDirection | isMovingFast | isOnCloseZone || shouldClose
-  //         0        |       0      |       0       ||    0
-  //         0        |       0      |       1       ||    1
-  //         0        |       1      |       0       ||    0
-  //         0        |       1      |       1       ||    0
-  //         1        |       0      |       0       ||    0
-  //         1        |       0      |       1       ||    1
-  //         1        |       1      |       0       ||    1
-  //         1        |       1      |       1       ||    1
-  // The resulting expression was generated by resolving the K-map (Karnaugh map):
-  let shouldClose = (!isMovingFast && isOnCloseZone) || (isCloseDirection && isMovingFast);
-  return shouldClose;
-}

src/components/menu/menu-controller.ts

@@ -132,7 +132,6 @@ export class MenuController {
       }
       return menu.open();
     }
-
     return Promise.resolve(false);
   }
 

src/components/menu/menu-gestures.ts

@@ -3,6 +3,7 @@ import { SlideEdgeGesture } from '../../gestures/slide-edge-gesture';
 import { SlideData } from '../../gestures/slide-gesture';
 import { assign } from '../../util/util';
 import { GestureController, GesturePriority } from '../../gestures/gesture-controller';
+import { NativeRafDebouncer } from '../../util/debouncer';
 
 /**
  * Gesture attached to the content which the menu is assigned to
@@ -11,15 +12,16 @@ export class MenuContentGesture extends SlideEdgeGesture {
 
   constructor(
     public menu: Menu,
-    gestureCtrl: GestureController,
     contentEle: HTMLElement,
+    gestureCtrl: GestureController,
     options: any = {}) {
     super(contentEle, assign({
       direction: 'x',
       edge: menu.side,
       threshold: 0,
       maxEdgeStart: menu.maxEdgeStart || 50,
       maxAngle: 40,
+      debouncer: new NativeRafDebouncer(),
       gesture: gestureCtrl.create('menu-swipe', {
         priority: GesturePriority.MenuSwipe,
       })

src/components/menu/menu.ts

@@ -2,7 +2,7 @@ import { ChangeDetectionStrategy, Component, ContentChild, ElementRef, EventEmit
 
 import { Backdrop } from '../backdrop/backdrop';
 import { Config } from '../../config/config';
-import { isTrueProperty } from '../../util/util';
+import { isTrueProperty, assert } from '../../util/util';
 import { Keyboard } from '../../util/keyboard';
 import { MenuContentGesture } from  './menu-gestures';
 import { MenuController } from './menu-controller';
@@ -199,6 +199,7 @@ export class Menu {
   private _isPers: boolean = false;
   private _init: boolean = false;
   private _events: UIEventManager = new UIEventManager();
+  private _gestureID: number;
 
   /**
    * @private
@@ -304,7 +305,9 @@ export class Menu {
     private _keyboard: Keyboard,
     private _zone: NgZone,
     private _gestureCtrl: GestureController
-  ) {}
+  ) {
+    this._gestureID = _gestureCtrl.newID();
+  }
 
   /**
    * @private
@@ -333,7 +336,7 @@ export class Menu {
     this.setElementAttribute('type', this.type);
 
     // add the gestures
-    this._cntGesture = new MenuContentGesture(this, this._gestureCtrl, document.body);
+    this._cntGesture = new MenuContentGesture(this, document.body, this._gestureCtrl);
 
     // register listeners if this menu is enabled
     // check if more than one menu is on the same side
@@ -472,6 +475,8 @@ export class Menu {
   }
 
   private _before() {
+    assert(!this._isAnimating, '_before() should not be called while animating');
+
     // this places the menu into the correct location before it animates in
     // this css class doesn't actually kick off any animations
     this.menuContent && this.menuContent.resize();
@@ -482,6 +487,7 @@ export class Menu {
   }
 
   private _after(isOpen: boolean) {
+    assert(this._isAnimating, '_before() should be called while animating');
     // keep opening/closing the menu disabled for a touch more yet
     // only add listeners/css if it's enabled and isOpen
     // and only remove listeners/css if it's not open
@@ -491,8 +497,10 @@ export class Menu {
 
     this._events.unlistenAll();
     if (isOpen) {
-      this._cntEle.classList.add('menu-content-open');
+      // Disable swipe to go back gesture
+      this._gestureCtrl.disableGesture('goback-swipe', this._gestureID);
 
+      this._cntEle.classList.add('menu-content-open');
       let callback = this.onBackdropClick.bind(this);
       this._events.pointerEvents({
         element: this._cntEle,
@@ -505,6 +513,9 @@ export class Menu {
       this.ionOpen.emit(true);
 
     } else {
+      // Enable swipe to go back gesture
+      this._gestureCtrl.enableGesture('goback-swipe', this._gestureID);
+
       this._cntEle.classList.remove('menu-content-open');
       this.setElementClass('show-menu', false);
       this.backdrop.setElementClass('show-menu', false);

src/components/modal/test/basic/app-module.ts

@@ -147,13 +147,15 @@ export class E2EPage {
         </ion-item>
       </ion-list>
       <button ion-button full (click)="submit()">Submit</button>
-      <p>ionViewCanEnter ({{called.ionViewCanEnter}})</p>
-      <p>ionViewCanLeave ({{called.ionViewCanLeave}})</p>
-      <p>ionViewDidLoad ({{called.ionViewDidLoad}})</p>
-      <p>ionViewWillEnter ({{called.ionViewWillEnter}})</p>
-      <p>ionViewDidEnter ({{called.ionViewDidEnter}})</p>
-      <p>ionViewWillLeave ({{called.ionViewWillLeave}})</p>
-      <p>ionViewDidLeave ({{called.ionViewDidLeave}})</p>
+      <div padding>
+        <p>ionViewCanEnter ({{called.ionViewCanEnter}})</p>
+        <p>ionViewCanLeave ({{called.ionViewCanLeave}})</p>
+        <p>ionViewDidLoad ({{called.ionViewDidLoad}})</p>
+        <p>ionViewWillEnter ({{called.ionViewWillEnter}})</p>
+        <p>ionViewDidEnter ({{called.ionViewDidEnter}})</p>
+        <p>ionViewWillLeave ({{called.ionViewWillLeave}})</p>
+        <p>ionViewDidLeave ({{called.ionViewDidLeave}})</p>
+      </div>
     </ion-content>
   `,
   providers: [SomeComponentProvider]
@@ -505,10 +507,12 @@ export class ModalFirstPage {
   }
 
   ionViewWillLeave() {
+    console.log('ModalFirstPage ionViewWillLeave fired');
     this.called.ionViewWillLeave++;
   }
 
   ionViewDidLeave() {
+    console.log('ModalFirstPage ionViewDidLeave fired');
     this.called.ionViewDidLeave++;
   }
 
@@ -612,7 +616,8 @@ export class E2EApp {
   ],
   imports: [
     IonicModule.forRoot(E2EApp, {
-      statusbarPadding: true
+      statusbarPadding: true,
+      swipeBackEnabled: true
     })
   ],
   bootstrap: [IonicApp],

src/components/tabs/test/advanced/app-module.ts

@@ -346,7 +346,7 @@ export const deepLinkConfig: DeepLinkConfig = {
     Tab3Page1
   ],
   imports: [
-    IonicModule.forRoot(E2EApp, null, deepLinkConfig)
+    IonicModule.forRoot(E2EApp, {tabsHideOnSubPages: true}, deepLinkConfig)
   ],
   bootstrap: [IonicApp],
   entryComponents: [