feat(sidenav): add gestures to sidenav to allow dragging the sidenav

src/components/sidenav/demoSidenavDragging/index.html

@@ -0,0 +1,73 @@
+
+<div ng-controller="AppCtrl" layout="column" style="height:500px;" ng-cloak>
+
+  <section layout="row" flex>
+
+    <md-sidenav class="md-sidenav-left md-whiteframe-z2" md-component-id="left">
+
+      <md-toolbar class="md-theme-light">
+        <h1 class="md-toolbar-tools">Drag Enabled</h1>
+      </md-toolbar>
+      <md-content ng-controller="LeftCtrl" layout-padding>
+        <p>
+          This sidenav is able to be dragged. Through the drag gesture, it's possible to close the sidenav.
+        </p>
+        <md-button ng-click="close()" class="md-primary">
+          Close Sidenav Left
+        </md-button>
+      </md-content>
+
+    </md-sidenav>
+
+    <md-content flex layout-padding>
+
+      <div layout="column" layout-fill layout-align="top center">
+        <p>
+          You can simply close a sidenav by using a gesture. Simply drag the sidenav to close it.
+        </p>
+        <p>
+          The right sidenav allows dragging.
+        </p>
+        <p>
+          The left sidenav is disabled for dragging.
+        </p>
+
+        <div>
+          <md-button ng-click="toggleLeft()"
+            class="md-primary">
+            Toggle left
+          </md-button>
+        </div>
+
+        <div>
+          <md-button ng-click="toggleRight()"
+            ng-hide="isOpenRight()"
+            class="md-primary">
+            Toggle right
+          </md-button>
+        </div>
+      </div>
+
+      <div flex></div>
+
+    </md-content>
+
+    <md-sidenav class="md-sidenav-right md-whiteframe-z2" md-component-id="right" md-disable-drag="true">
+
+      <md-toolbar class="md-theme-indigo">
+        <h1 class="md-toolbar-tools">Drag Disabled</h1>
+      </md-toolbar>
+      <md-content layout-padding ng-controller="RightCtrl">
+        <md-button ng-click="close()" class="md-primary">
+          Close Sidenav Right
+        </md-button>
+        <p>
+          This sidenav disables the dragging gesture. It can be closed through the buttons.
+        </p>
+      </md-content>
+
+    </md-sidenav>
+
+  </section>
+
+</div>

src/components/sidenav/demoSidenavDragging/script.js

@@ -0,0 +1,27 @@
+angular
+  .module('sidenavDemo2', ['ngMaterial'])
+  .controller('AppCtrl', function ($scope, $timeout, $mdSidenav) {
+    $scope.toggleLeft = buildToggler('left');
+    $scope.toggleRight = buildToggler('right');
+
+    $scope.isOpenRight = function(){
+      return $mdSidenav('right').isOpen();
+    };
+
+    function buildToggler(navID) {
+      return function() {
+        $mdSidenav(navID).toggle()
+      }
+    }
+  })
+  .controller('LeftCtrl', function ($scope, $timeout, $mdSidenav) {
+    $scope.close = function () {
+      $mdSidenav('left').close();
+
+    };
+  })
+  .controller('RightCtrl', function ($scope, $timeout, $mdSidenav) {
+    $scope.close = function () {
+      $mdSidenav('right').close();
+    };
+  });

src/components/sidenav/sidenav.js

@@ -197,6 +197,7 @@ function SidenavFocusDirective() {
  * @param {expression=} md-is-open A model bound to whether the sidenav is opened.
  * @param {boolean=} md-disable-backdrop When present in the markup, the sidenav will not show a backdrop.
  * @param {string=} md-component-id componentId to use with $mdSidenav service.
+ * @param {boolean=} md-disable-drag Disables the abbility to drag the sidenav
  * @param {expression=} md-is-locked-open When this expression evalutes to true,
  * the sidenav 'locks open': it falls into the content's flow instead
  * of appearing over it. This overrides the `md-is-open` attribute.
@@ -209,7 +210,7 @@ function SidenavFocusDirective() {
  *   - `<md-sidenav md-is-locked-open="$mdMedia('min-width: 1000px')"></md-sidenav>`
  *   - `<md-sidenav md-is-locked-open="$mdMedia('sm')"></md-sidenav>` (locks open on small screens)
  */
-function SidenavDirective($mdMedia, $mdUtil, $mdConstant, $mdTheming, $animate, $compile, $parse, $log, $q, $document) {
+function SidenavDirective($mdMedia, $mdUtil, $mdConstant, $mdTheming, $animate, $mdGesture, $parse, $log, $q, $document, $timeout) {
   return {
     restrict: 'E',
     scope: {
@@ -265,6 +266,8 @@ function SidenavDirective($mdMedia, $mdUtil, $mdConstant, $mdTheming, $animate,
     scope.$watch(isLocked, updateIsLocked);
     scope.$watch('isOpen', updateIsOpen);
 
+    // Enable dragging
+    if (!angular.isDefined(attr.mdDisableDrag) || !attr.mdDisableDrag) enableDragging();
 
     // Publish special accessor for the Controller instance
     sidenavCtrl.$toggleOpen = toggleOpen;
@@ -335,6 +338,101 @@ function SidenavDirective($mdMedia, $mdUtil, $mdConstant, $mdTheming, $animate,
       }
     }
 
+    function enableDragging() {
+      $mdGesture.register(element, 'drag', { horizontal: true });
+
+      element
+        .on('$md.dragstart', onDragStart)
+        .on('$md.drag', onDrag)
+        .on('$md.dragend', onDragEnd);
+
+      var style = getComputedStyle(element[0]);
+      var sidenavWidth = parseInt(style.width);
+      var isRightSidenav = element.hasClass('md-sidenav-right');
+      var accelerationBound = 6;
+
+      var dragCancelled = false;
+      var dragPercentage;
+      var lastOpenState;
+      var lastDistance = 0;
+      var isQuickDrag = false;
+
+      function onDragStart() {
+        if (element.hasClass('md-locked-open')) {
+          dragCancelled = true;
+        } else {
+          lastOpenState = scope.isOpen;
+          element.css($mdConstant.CSS.TRANSITION_DURATION, '0ms');
+        }
+      }
+
+      function onDrag(ev) {
+        if (dragCancelled) return;
+
+        if (!isQuickDrag) {
+          var distance = lastDistance - ev.pointer.distanceX;
+          // When the current partial drag distance is bigger than the acceleration bound, then we can
+          // identify it as a quick drag.
+          isQuickDrag = isRightSidenav ? distance <= -accelerationBound : distance >= accelerationBound;
+        } else if (isRightSidenav && lastDistance > ev.pointer.distanceX ||
+                   !isRightSidenav && lastDistance < ev.pointer.distanceX) {
+          // When the users drags the sidenav backward, then we can reset the quick drag state.
+          isQuickDrag = false;
+        }
+
+        dragPercentage = Math.round((ev.pointer.distanceX / sidenavWidth) * 100);
+        if (!isRightSidenav) dragPercentage = 0 - dragPercentage;
+
+        if (dragPercentage > 100) dragPercentage = 100;
+        else if (dragPercentage < 0) dragPercentage = 0;
+
+        element.css($mdConstant.CSS.TRANSFORM, 'translate3d(-' + (isRightSidenav ? 100 - dragPercentage : dragPercentage) + '%,0,0)');
+        lastDistance = ev.pointer.distanceX;
+      }
+
+      function onDragEnd() {
+        if (dragCancelled) {
+          dragCancelled = false;
+          return;
+        }
+
+        var remainingPercentage = 100 - dragPercentage;
+        var animationTime = 4 * remainingPercentage;
+        var shouldClose = dragPercentage > 50 || isQuickDrag;
+
+        // This validates the correct translate value. The invert is here required, because a right
+        // aligned sidenav will transition in the other direction.
+        var endTranslate = shouldClose ? isRightSidenav ? 0 : -100 : isRightSidenav ? -100 : 0;
+
+        element.css($mdConstant.CSS.TRANSITION_DURATION, animationTime + "ms");
+        element.css($mdConstant.CSS.TRANSFORM, 'translate3d(' + endTranslate +  '%,0,0)');
+
+        // Reset drag
+        lastDistance = 0;
+        isQuickDrag = false;
+
+        // Invert shouldClose here, because we need to know if the sidenav should open.
+        $timeout(onAnimationDone, animationTime, true, !shouldClose);
+      }
+
+      function onAnimationDone(isOpen) {
+        scope.isOpen = isOpen;
+        element.css($mdConstant.CSS.TRANSFORM, '');
+        element.css($mdConstant.CSS.TRANSITION_DURATION, '');
+
+        if (isOpen) {
+          if (!lastOpenState && backdrop) {
+            $animate.enter(backdrop, element.parent());
+          }
+
+          element.removeClass('_md-closed');
+        } else {
+          if (backdrop) $animate.leave(backdrop);
+          element.addClass('_md-closed');
+        }
+      }
+    }
+
     /**
      * Toggle the sideNav view and publish a promise to be resolved when
      * the view animation finishes.

src/components/sidenav/sidenav.scss

@@ -14,6 +14,9 @@ md-sidenav {
   overflow: auto;
   -webkit-overflow-scrolling: touch;
 
+  // This allows the most browsers to setup appropriate optimizations before the animation runs.
+  will-change: transform;
+
   ul {
     list-style: none;
   }