React Native navigator ref property - facebook

Question

I am trying to follow the example (https://github.com/facebook/react-native/tree/master/Examples/UIExplorer/Navigator) on the react native site to set up my navigator, but I can't seem to get it to work. Right now I am having trouble with the ref property, as when its calls _setNavigatorRef, I am getting an error that it cannot find the property _navigator of null in the following code. It works in the example but I am not sure why:
index.ios.js
'use strict';
var React = require('react-native');
var DataEntry = require('./app/DataEntry');
var PasswordView = require('./app/PasswordView');
var GoogSignIn = require('./app/GoogSignIn');
var {
AppRegistry,
Image,
StyleSheet,
Text,
View,
Navigator,
TouchableOpacity,
} = React;
class PasswordRecovery extends React.Component {
render() {
return (
<Navigator
ref={this._setNavigatorRef}
style={styles.container}
initialRoute={{id: 'GoogSignIn', name: 'Index'}}
renderScene={this.renderScene}
configureScene={(route) => {
if (route.sceneConfig) {
return route.sceneConfig;
}
return Navigator.SceneConfigs.FloatFromRight;
}} />
);
}
renderScene(route, navigator) {
switch (route.id) {
case 'GoogSignIn':
return <GoogSignIn navigator={navigator} />;
case 'DataEntry':
return <DataEntry navigator={navigator} />;
case 'PasswordView':
return <PasswordView navigator={navigator} />;
default:
return this.noRoute(navigator);
}
noRoute(navigator) {
return (
<View style={{flex: 1, alignItems: 'stretch', justifyContent: 'center'}}>
<TouchableOpacity style={{flex: 1, alignItems: 'center', justifyContent: 'center'}}
onPress={() => navigator.pop()}>
<Text style={{color: 'red', fontWeight: 'bold'}}>ERROR: NO ROUTE DETECTED</Text>
</TouchableOpacity>
</View>
);
}
_setNavigatorRef(navigator) {
if (navigator !== this._navigator) {
this._navigator = navigator;
if (navigator) {
var callback = (event) => {
console.log(
`TabBarExample: event ${event.type}`,
{
route: JSON.stringify(event.data.route),
target: event.target,
type: event.type,
}
);
};
// Observe focus change events from the owner.
this._listeners = [
navigator.navigationContext.addListener('willfocus', callback),
navigator.navigationContext.addListener('didfocus', callback),
];
}
}
}
componentWillUnmount() {
this._listeners && this._listeners.forEach(listener => listener.remove());
}
}
var styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#F5FCFF',
},
welcome: {
fontSize: 20,
textAlign: 'center',
margin: 10,
},
instructions: {
textAlign: 'center',
color: '#333333',
marginBottom: 5,
},
});
AppRegistry.registerComponent('PasswordRecovery', () => PasswordRecovery);
I am just trying to get this all setup so that I can display a Google Sign in scene and then navigate from there. The code for that scene so far is here:
GoogSignIn.js
'use strict';
var React = require('react-native');
var { NativeAppEventEmitter } = require('react-native');
var GoogleSignin = require('react-native-google-signin');
var cssVar = require('cssVar');
var { Icon } = require('react-native-icons');
var {
AppRegistry,
StyleSheet,
Text,
View,
TouchableOpacity,
TouchableHighlight,
PixelRatio,
Navigator,
} = React;
var NavigationBarRouteMapper = {
LeftButton: function(route, navigator, index, navState) {
if (index === 0) {
return null;
}
var previousRoute = navState.routeStack[index - 1];
return (
<TouchableOpacity
onPress={() => navigator.pop()}
style={styles.navBarLeftButton}>
<Text style={[styles.navBarText, styles.navBarButtonText]}>
{previousRoute.title}
</Text>
</TouchableOpacity>
);
},
RightButton: function(route, navigator, index, navState) {
return (
null
);
},
Title: function(route, navigator, index, navState) {
return (
<Text style={[styles.navBarText, styles.navBarTitleText]}>
GOOGLE SIGN IN
</Text>
);
},
};
class GoogSignin extends React.Component {
constructor(props) {
super(props);
this.state = {
user: null
};
}
componentWillMount() {
var navigator = this.props.navigator;
var callback = (event) => {
console.log(
`NavigationBarSample : event ${event.type}`,
{
route: JSON.stringify(event.data.route),
target: event.target,
type: event.type,
}
);
};
// Observe focus change events from this component.
this._listeners = [
navigator.navigationContext.addListener('willfocus', callback),
navigator.navigationContext.addListener('didfocus', callback),
];
}
componentWillUnmount() {
this._listeners && this._listeners.forEach(listener => listener.remove());
}
componentDidMount() {
this._configureOauth(
'105558473349-7usegucirv10bruohtogd0qtuul3kkhn.apps.googleusercontent.com'
);
}
renderScene(route, navigator) {
console.log("HERE");
return (
<View style={styles.container}>
<TouchableHighlight onPress={() => {this._signIn(); }}>
<View style={{backgroundColor: '#f44336', flexDirection: 'row'}}>
<View style={{padding: 12, borderWidth: 1/2, borderColor: 'transparent', borderRightColor: 'white'}}>
<Icon
name='ion|social-googleplus'
size={24}
color='white'
style={{width: 24, height: 24}}
/>
</View>
<Text style={{color: 'white', padding: 12, marginTop: 2, fontWeight: 'bold'}}>Sign in with Google</Text>
</View>
</TouchableHighlight>
</View>
);
}
render() {
return (
<Navigator
debugOverlay={false}
style={styles.appContainer}
renderScene={this.renderScene}
navigationBar={
<Navigator.NavigationBar
routeMapper={NavigationBarRouteMapper}
style={styles.navBar}/>
}/>
);
}
_configureOauth(clientId, scopes=[]) {
console.log("WE HERE")
GoogleSignin.configure(clientId, scopes);
NativeAppEventEmitter.addListener('googleSignInError', (error) => {
console.log('ERROR signin in', error);
});
NativeAppEventEmitter.addListener('googleSignIn', (user) => {
console.log(user);
this.setState({user: user});
});
return true;
}
_signIn() {
GoogleSignin.signIn();
}
_signOut() {
GoogleSignin.signOut();
this.setState({user: null});
}
};
var styles = StyleSheet.create({
container: {
flex: 1,
justifyContent: 'center',
alignItems: 'center',
backgroundColor: '#F5FCFF',
},
messageText: {
fontSize: 17,
fontWeight: '500',
padding: 15,
marginTop: 50,
marginLeft: 15,
},
button: {
backgroundColor: 'white',
padding: 15,
borderBottomWidth: 1 / PixelRatio.get(),
borderBottomColor: '#CDCDCD',
},
buttonText: {
fontSize: 17,
fontWeight: '500',
},
navBar: {
backgroundColor: 'white',
},
navBarText: {
fontSize: 16,
marginVertical: 10,
},
navBarTitleText: {
color: cssVar('fbui-bluegray-60'),
fontWeight: '500',
marginVertical: 9,
},
navBarLeftButton: {
paddingLeft: 10,
},
navBarRightButton: {
paddingRight: 10,
},
navBarButtonText: {
color: cssVar('fbui-accent-blue'),
},
scene: {
flex: 1,
paddingTop: 20,
backgroundColor: '#EAEAEA',
},
});
module.exports = GoogSignin;

Answer 1

I suspect it's a context issue. On your Navigator component, try converting from this:
ref={this._setNavigatorRef}
To this:
ref={(navigator) => this._setNavigatorRef(navigator)} (prettier IMHO)
or this:
ref={this._setNavigatorRef.bind(this)}