Better event handling for taps

js/framework/framework-events.js

@@ -6,6 +6,8 @@
  * Framework events handles various mobile browser events, and 
  * detects special events like tap/swipe/etc. and emits them
  * as custom events that can be used in an app.
+ *
+ * Portions lovingly adapted from github.com/maker/ratchet and github.com/alexgibson/tap.js - thanks guys!
  */
 
 (function(window, document, framework) {
@@ -14,15 +16,21 @@
   // A map of event types that we virtually detect and emit
   framework.EventController.prototype.VIRTUAL_EVENT_TYPES = ['tap', 'swipeleft', 'swiperight'];
 
-  // Some convenient top-level event functions
+  
+  /**
+   * Trigger a new event.
+   */
+  framework.EventController.prototype.trigger = function(eventType, data) {
+    // TODO: Do we need to use the old-school createEvent stuff?
 
-  framework.trigger = function(type, data) {
-    window.dispatchEvent(new CustomEvent(type, {
-      detail: data
-    }));
+    window.dispatchEvent(new CustomEvent(eventType, data));
   };
-
-  framework.on = function(type, callback, element) {
+  
+  /**
+   * Shorthand for binding a new event listener to the given
+   * event type.
+   */
+  framework.EventController.prototype.on = function(type, callback, element) {
     var i;
     var e = element || window;
     /*
@@ -40,29 +48,71 @@
     e.addEventListener(type, callback);
   };
 
-  var _touchStart = function(event) {
-    console.log("EVENT: touchstart", event);
-    framework.EventController.isTouching = true;
+
+  /**
+   * Process a touchstart event.
+   */
+  framework.EventController.prototype.handleTouchStart = function(e) {
+    console.log("EVENT: touchstart", e);
+    if(e.type === 'touchstart') {
+      // We are now touching
+      this._isTouching = true;
+    }
+    
+    // Reset the movement indicator
+    this._hasMoved = false;
+
+    // Store touch coords
+    this._touchStartX = e.type === 'touchstart' ? e.touches[0].clientX : e.clientX;
+    this._touchStartY = e.type === 'touchstart' ? e.touches[0].clientY : e.clientY;
   };
 
-  var _touchMove = function(event) {
-    console.log("EVENT: touchmove", event);
+  /**
+   * Process a touchmove event.
+   */
+  framework.EventController.prototype.handleTouchMove = function(e) {
+    console.log("EVENT: touchmove", e);
+
+    var x = e.type === 'touchmove' ? e.touches[0].clientX : e.clientX,
+        y = e.type === 'touchmove' ? e.touches[0].clientY : e.clientY;
+
+    // Check if the finger moved more than 10px, and then indicate we should cancel the tap
+    if (Math.abs(x - this._touchStartX) > 10 || Math.abs(y - this._touchStartY) > 10) {
+      this._hasMoved = true;
+      console.log('DID MOVE');
+    }
   };
 
-  var _touchEnd = function(event) {
-    console.log("EVENT: touchend", event);
-    if(framework.EventController.isTouching) {
+  /**
+   * Process a touchend event.
+   */
+  framework.EventController.prototype.handleTouchEnd = function(e) {
+    console.log("EVENT: touchend", e);
+
+    if(this._isTouching && !this._hasMoved) {
       console.log("EVENT: (virtual) tap", event);
       framework.trigger('tap', {
+        bubbles: true,
+        cancelable: true
       });
     }
-    framework.EventController.isTouching = false;
+    framework.EventController._isTouching = false;
+  };
+
+
+  /**
+   * Process a touchcancel event.
+   */
+  framework.EventController.prototype.handleTouchCancel = function(e) {
+    this._hasMoved = false;
+    this._touchStartX = null;
+    this._touchStartY = null;
   };
 
   // With a click event, we need to check the target
   // and if it's an internal target that doesn't want
   // a click, cancel it
-  var _click = function(e) {
+  framework.EventController.prototype.handleClick = function(e) {
     var target = e.target;
 
     if (
@@ -84,17 +134,27 @@
     }
     // We need to cancel this one
     e.preventDefault();
+
+    // TODO: should we do this?
+    // e.stopPropagation();
   }
   
-  var _popstate = function(event) {
+  framework.EventController.prototype.handlePopState = function(event) {
     console.log("EVENT: popstate", event);
   }
+  
+  
+  // Map some convenient top-level functions for event handling
+  framework.on = framework.EventController.prototype.on;
+  framework.trigger = framework.EventController.prototype.trigger;
+
 
   // Set up various listeners
-  window.addEventListener('touchstart', _touchStart);
-  window.addEventListener('touchmove', _touchMove);
-  window.addEventListener('touchend', _touchEnd);
-  window.addEventListener('click', _click);
-  window.addEventListener('popstate', _popstate);
+  window.addEventListener('touchstart', framework.EventController.prototype.handleTouchStart);
+  window.addEventListener('touchmove', framework.EventController.prototype.handleTouchMove);
+  window.addEventListener('touchcancel', framework.EventController.prototype.handleTouchCancel);
+  window.addEventListener('touchend', framework.EventController.prototype.handleTouchEnd);
+  window.addEventListener('click', framework.EventController.prototype.handleClick);
+  window.addEventListener('popstate', framework.EventController.prototype.handlePopState);
 
 })(this, document, FM = this.FM || {});