Add back android support

README.md

@@ -52,7 +52,6 @@ const firstRoute = {
 class MyApp extends React.Component {
 
   render() {
-
     return (
       <Router
         firstRoute={firstRoute}
@@ -107,6 +106,7 @@ The **`<Router \>`** object used to initialize the navigation can take the follo
 - `rightCorner`: If you have the same occuring action buttons on the right side of your navigation bar (like the Twitter "Compose"-button), you can specify a component for that view.
 - `customAction`: A special callback prop for your action buttons (this can be handy for triggering a side menu for example). The action gets triggered from your custom `leftCorner` or `rightCorner` components by calling `this.props.customAction("someActionName")` from them. It is then picked up like this: `<Router customAction={this.doSomething} />`.
 - `hideNavigationBar`: Hide the navigation bar, always
+- `handleBackAndroid` (Boolean value): Apply a listener to the native back button on Android. On click, it will go to the previous route until it reach the first scene, then it will exit the app.
 
 The **`this.props.toRoute()`** callback prop takes one parameter (a JavaScript object) which can have the following keys:
 - `name`: The name of your route, which will be shown as the title of the navigation bar unless it is changed.

components/NavBarContainer.js

@@ -1,4 +1,4 @@
-import React, { StyleSheet, View, PropTypes } from 'react-native';
+import React, { StyleSheet, View, PropTypes, Platform, BackAndroid } from 'react-native';
 
 import NavBarContent from './NavBarContent';
 
@@ -8,6 +8,7 @@ const propTypes = {
   borderColor: PropTypes.string,
   currentRoute: PropTypes.object.isRequired,
   customAction: PropTypes.func,
+  handleBackAndroid: PropTypes.bool,
   leftProps: PropTypes.object,
   navigator: PropTypes.object.isRequired,
   rightCorner: PropTypes.func,
@@ -50,6 +51,19 @@ class NavBarContainer extends React.Component {
     });
   }
 
+  componentDidMount() {
+    if (Platform.OS === 'android' && !!this.props.handleBackAndroid) {
+      BackAndroid.addEventListener('hardwareBackPress', () => {
+        if (this.props.currentRoute.index > 0) {
+          this.goBack();
+          return true;
+        }
+
+        return false;
+      });
+    }
+  }
+
   componentWillReceiveProps(newProps) {
     if (this.props && this.props.currentRoute.index !== newProps.currentRoute.index) {
       this.setState({
@@ -58,6 +72,12 @@ class NavBarContainer extends React.Component {
     }
   }
 
+  componentWillUnmount() {
+    if (Platform.OS === 'android' && !!this.props.handleBackAndroid) {
+      BackAndroid.removeEventListener('hardwareBackPress');
+    }
+  }
+
   goBack() {
     this.props.toBack(this.props.navigator);
   }

index.js

@@ -207,6 +207,7 @@ class Router extends React.Component {
           rightProps={this.state.rightProps}
           titleProps={this.state.titleProps}
           customAction={this.customAction}
+          handleBackAndroid={this.props.handleBackAndroid}
         />
       );
     }