问题
I want to reload the tabNavigator when the user changse the tab each time. the lifecycle method of react native doesn't get called when user changes the tab. Then how can it be possible to reload tab in TabNavigator :
The below example have two Tabs : 1) Home 2)Events. Now I want to refresh the event Tab when user returns from the home tab.
EXPO LINK : Expo Tab Navigator
Code :
import React, {Component} from 'react';
import {View, StyleSheet, Image, FlatList, ScrollView, Dimensions } from 'react-native';
import { Button, List, ListItem, Card } from 'react-native-elements' // 0.15.0
//import { Constants } from 'expo';
import { TabNavigator, StackNavigator } from 'react-navigation'; // 1.0.0-beta.11
//image screen width and height defs
const windowWidth = Dimensions.get('window').width;
const windowHeight = Dimensions.get('window').height;
export default class App extends Component {
render() {
//const { navigate } = this.props.navigation;
return (
<TabsNav />
)
}
}
class MyHomeScreen extends Component {
render() {
return (
<View>
<Image
resizeMode="cover"
style={{ width: windowWidth * .85, height: windowHeight * 0.3}}
source={{uri: 'http://www.ajaxlibrary.ca/sites/default/files/media/logo.png?s358127d1501607090'}}
/>
<Button
onPress={() => this.props.navigation.navigate('Notifications')}
title="Go to notifications"
/>
</View>
);
}
}
class AplEvents extends Component {
static navigationOptions = {
tabBarLabel: 'Events List',
tabBarIcon: ({ tintColor }) => (
<Image
source={{uri: 'https://facebook.github.io/react/img/logo_og.png'}}
style={[styles.icon, {tintColor: tintColor}]}
/>
),
};
constructor(props) {
super(props);
this.state = {
data: [],
error: null,
};
}
// when component mounts run the function fetch
componentDidMount() {
this.makeRemoteRequest();
}
makeRemoteRequest = () => {
const url = `http://www.ajaxlibrary.ca/?q=calendar-test`;
fetch(url)
.then((res) => res.json())
.then((res) => {
this.setState({
data: [...this.state.data, ...res.nodes],
error: res.error || null,
});
})
.catch(error => {
this.setState( error );
});
};
render() {
const { navigate } = this.props.navigation;
return (
<List containerStyle={{ marginTop: 0, borderTopWidth: 0, borderBottomWidth: 0 }}>
<FlatList
data={this.state.data}
renderItem={({ item }) => (
<ListItem
//squareAvatar
title={`${item.node.title}\n${item.node.Program_Location}`}
subtitle={item.node.Next_Session}
avatar={{ uri: item.node.Image }}
containerStyle={{ borderBottomWidth: 0 }}
// save params to pass to detailed events screen
onPress={() => navigate('Details', {title: `${item.node.title}`,
body: `${item.node.Body}`,
date: `${item.node.Date}`,
Next_Session: `${item.node.Next_Session}`,
Program_Location: `${item.node.Program_Location}`,
Nid: `${item.node.Nid}`,
Image: `${item.node.Image}`,
Run_Time: `${item.node.Run_Time}`})}
/>
)}
keyExtractor={item => item.node.Nid}
/>
</List>
);
}
}
class EventDetails extends Component {
static navigationOptions = {
title: 'EventDetails'
};
render() {
const { params } = this.props.navigation.state;
let pic = {
uri: `${params.Image}`
};
//const pic = { params.Image };
return (
<ScrollView>
<Card
title={params.title}
>
<Image
resizeMode="cover"
style={{ width: windowWidth * .85, height: windowHeight * 0.3}}
source={pic}
/>
<Button style={{marginTop: 10}}
icon={{name: 'date-range'}}
backgroundColor='#03A9F4'
fontFamily='Lato'
buttonStyle={{borderRadius: 0, marginLeft: 0, marginRight: 0, marginBottom: 0}}
title='Add to Calendar'
/>
<ListItem
title="Event Description"
subtitle={params.body}
hideChevron='true'
/>
<ListItem
title="Date"
subtitle={`${params.Next_Session}\n Run Time - ${params.Run_Time}`}
hideChevron='true'
/>
<ListItem
title="Location"
subtitle={params.Program_Location}
hideChevron='true'
/>
</Card>
</ScrollView>
);
}
}
const styles = StyleSheet.create({
icon: {
width: 26,
height: 26,
},
});
const EventStack = StackNavigator({
EventList: {
screen: AplEvents,
navigationOptions: {
title: "APL Event Listing",
}
},
Details: {
screen: EventDetails,
},
TabsNav: { screen: MyHomeScreen}
});
const TabsNav = TabNavigator({
Home: {
screen: MyHomeScreen,
navigationOptions: {
tabBarLabel: 'Home',
tabBarIcon: ({ tintColor }) => (
<Image
source={{uri: 'https://upload.wikimedia.org/wikipedia/de/thumb/9/9f/Twitter_bird_logo_2012.svg/154px-Twitter_bird_logo_2012.svg.png'}}
style={[styles.icon, {tintColor: tintColor}]}
/>
),
},
},
EventList: {
screen: EventStack,
navigationOptions: {
tabBarLabel: 'Events',
tabBarIcon: ({ tintColor }) => (
<Image
source={{uri: 'https://upload.wikimedia.org/wikipedia/de/thumb/9/9f/Twitter_bird_logo_2012.svg/154px-Twitter_bird_logo_2012.svg.png'}}
style={[styles.icon, {tintColor: tintColor}]}
/>
),
},
},
}, {
tabBarOptions: {
activeTintColor: '#e91e63',
},
});
回答1:
There's many long discussion about this from react-native issue 314, 486, 1335, and finally we got a way to handle this, after Sep 27, 2017, react-navigation version v1.0.0-beta.13:
New Features
Accept a tabBarOnPress param (#1335) - @cooperka
So here we go,
Usage:
const MyTabs = TabNavigator({
...
}, {
tabBarComponent: TabBarBottom /* or TabBarTop */,
tabBarPosition: 'bottom' /* or 'top' */,
navigationOptions: ({ navigation }) => ({
tabBarOnPress: (scene, jumpToIndex) => {
console.log('onPress:', scene.route);
jumpToIndex(scene.index);
},
}),
});
回答2:
I wasn't able to get this to work, and after checking the React Navigation documentation, found this, which seems to suggest that later versions (I'm using 1.0.0-beta.27) changed the method signature to a single object:
tabBarOnPress Callback to handle tap events; the argument is an object containing:
the previousScene: { route, index } which is the scene we are leaving
the scene: { route, index } that was tapped
the jumpToIndex method that can perform the navigation for you
https://reactnavigation.org/docs/en/tab-navigator.html#tabbaronpress
Given that, and the code from beausmith here, I put this together.
navigationOptions: ({ navigation }) => ({
tabBarOnPress: (args) => {
if (args.scene.focused) { // if tab currently focused tab
if (args.scene.route.index !== 0) { // if not on first screen of the StackNavigator in focused tab.
navigation.dispatch(NavigationActions.reset({
index: 0,
actions: [
NavigationActions.navigate({ routeName: args.scene.route.routes[0].routeName }) // go to first screen of the StackNavigator
]
}))
}
} else {
args.jumpToIndex(args.scene.index) // go to another tab (the default behavior)
}
}
})
Note that you'll need to import NavigationActions from react-navigation for this to work.
Hope this helps somebody :)
来源:https://stackoverflow.com/questions/46300603/how-to-reload-view-tap-on-tabnavigator-in-react-native