fix: fix tabBarOnPress with MaterialTopTabs and fix isFocused (#21)

* Hook up tabBarOnPress

* Move onTabPress logic to createTabNavigator

* Use old logic for determining focus state

* Use navigation.isFocused()

* Reorder jumpTo/onTabPress

* react-native-tab-view@0.0.78

packages/bottom-tabs/src/navigators/createMaterialTopTabNavigator.js

@@ -45,14 +45,6 @@ class TabView extends React.PureComponent<Props> {
     return route.routeName;
   };
 
-  _getOnPress = (previousScene, { route }) => {
-    const { descriptors } = this.props;
-    const descriptor = descriptors[route.key];
-    const options = descriptor.options;
-
-    return options.tabBarOnPress;
-  };
-
   _getTestIDProps = ({ route, focused }) => {
     const { descriptors } = this.props;
     const descriptor = descriptors[route.key];
@@ -107,6 +99,7 @@ class TabView extends React.PureComponent<Props> {
         getLabelText={this.props.getLabelText}
         getTestIDProps={this._getTestIDProps}
         renderIcon={this._renderIcon}
+        onTabPress={this.props.onTabPress}
       />
     );
   };

packages/bottom-tabs/src/utils/createTabNavigator.js

@@ -74,23 +74,14 @@ export default function createTabNavigator(TabView: React.ComponentType<*>) {
       const { descriptors } = this.props;
       const descriptor = descriptors[route.key];
       const { navigation, options } = descriptor;
+      const focused = navigation.isFocused();
 
       if (options.tabBarOnPress) {
-        options.tabBarOnPress({
-          navigation,
-        });
-      } else {
-        const isFocused =
-          this.props.navigation.state.index ===
-          this.props.navigation.state.routes.indexOf(route);
-
-        if (isFocused) {
-          if (route.hasOwnProperty('index') && route.index > 0) {
-            navigation.dispatch(StackActions.popToTop({ key: route.key }));
-          } else {
-            // TODO: do something to scroll to top
-          }
-        }
+        options.tabBarOnPress({ navigation });
+      } else if (focused && route.hasOwnProperty('index') && route.index > 0) {
+        navigation.dispatch(StackActions.popToTop({ key: route.key }));
+      } else if (focused) {
+        // TODO: do something to scroll to top
       }
     };
 

packages/bottom-tabs/src/views/BottomTabBar.js

@@ -201,8 +201,8 @@ class TabBarBottom extends React.Component<Props> {
             <TouchableWithoutFeedback
               key={route.key}
               onPress={() => {
-                jumpTo(route.key);
                 onTabPress({ route });
+                jumpTo(route.key);
               }}
             >
               <View