Improve TouchableOpacity

Summary:
I was comparing `<TouchableOpacity>` to `UIButton` in iOS and it just doesn't feel native. The initial delay was fixed by https://github.com/facebook/react-native/pull/10866 but still there is a lag between button release and animation.

I'm also not sure what `_hideTimeout` was used for. When logging `touchableHandle*` events looks like `touchableHandleActivePressIn` is called first, then `touchableHandleActivePressOut` and then `touchableHandlePress`. Which means the fade in animation from `touchableHandleActivePressOut` was interrupted by `touchableHandlePress`.

Reviewed By: vjeux

Differential Revision: D4309789

fbshipit-source-id: b6d4df544952e11c2ade97d860531cbb2fada36b

Libraries/Components/Touchable/TouchableOpacity.js

@@ -14,6 +14,7 @@
 // Note (avik): add @flow when Flow supports spread properties in propTypes
 
 var Animated = require('Animated');
+var Easing = require('Easing');
 var NativeMethodsMixin = require('NativeMethodsMixin');
 var React = require('React');
 var TimerMixin = require('react-timer-mixin');
@@ -84,10 +85,15 @@ var TouchableOpacity = React.createClass({
   /**
    * Animate the touchable to a new opacity.
    */
-  setOpacityTo: function(value: number, duration: number = 150) {
+  setOpacityTo: function(value: number, duration: number) {
     Animated.timing(
       this.state.anim,
-      {toValue: value, duration: duration, useNativeDriver: true}
+      {
+        toValue: value,
+        duration: duration,
+        easing: Easing.inOut(Easing.quad),
+        useNativeDriver: true,
+      }
     ).start();
   },
 
@@ -96,8 +102,6 @@ var TouchableOpacity = React.createClass({
    * defined on your component.
    */
   touchableHandleActivePressIn: function(e: Event) {
-    this.clearTimeout(this._hideTimeout);
-    this._hideTimeout = null;
     if (e.dispatchConfig.registrationName === 'onResponderGrant') {
       this._opacityActive(0);
     } else {
@@ -107,19 +111,11 @@ var TouchableOpacity = React.createClass({
   },
 
   touchableHandleActivePressOut: function(e: Event) {
-    if (!this._hideTimeout) {
-      this._opacityInactive();
-    }
+    this._opacityInactive(250);
     this.props.onPressOut && this.props.onPressOut(e);
   },
 
   touchableHandlePress: function(e: Event) {
-    this.clearTimeout(this._hideTimeout);
-    this._opacityActive(150);
-    this._hideTimeout = this.setTimeout(
-      this._opacityInactive,
-      this.props.delayPressOut || 100
-    );
     this.props.onPress && this.props.onPress(e);
   },
 
@@ -152,13 +148,11 @@ var TouchableOpacity = React.createClass({
     this.setOpacityTo(this.props.activeOpacity, duration);
   },
 
-  _opacityInactive: function() {
-    this.clearTimeout(this._hideTimeout);
-    this._hideTimeout = null;
+  _opacityInactive: function(duration: number) {
     var childStyle = flattenStyle(this.props.style) || {};
     this.setOpacityTo(
       childStyle.opacity === undefined ? 1 : childStyle.opacity,
-      150
+      duration
     );
   },