I'm trying to get React Native to whistle 3 times before a timer, so for example, whistle 3 seconds in a row, then let the timer go, then whistle again, but for some reason it is only doing it twice, it's skipping the middle whistle and sometimes the last one.
I've tried mounting the sound before hand, reducing the sound duration to about .3 seconds, and it is still skipping some plays. I know I need to do some refactor on the timers, but I think at least playing the sound should work.
import {
View,
Text,
StyleSheet,
TouchableOpacity,
Dimensions,
Vibration,
} from "react-native";
import React from "react";
import { StatusBar } from "expo-status-bar";
import { Audio } from "expo-av";
const screen = Dimensions.get("window");
let timeout: NodeJS.Timeout | undefined = undefined;
interface TimerComponentProps {
timeInSeconds?: number;
}
export const TimerComponent: React.FC<TimerComponentProps> = ({
timeInSeconds = 5,
}) => {
const [remaningSeconds, setRemainingSeconds] = React.useState(timeInSeconds);
const [isActive, setIsActive] = React.useState(false);
const [sound, setSound] = React.useState<Audio.Sound | undefined>(undefined);
const [shouldCount, setShouldCount] = React.useState(false);
const [counter, setCounter] = React.useState(3);
const { minutes, seconds } = React.useMemo(() => {
const minutes = Math.floor(remaningSeconds / 60);
const seconds = remaningSeconds % 60;
return { minutes, seconds };
}, [remaningSeconds]);
async function mountSound() {
try {
const { sound } = await Audio.Sound.createAsync(
require("../../assets/audio/Whistle.wav")
);
setSound(sound);
} catch (error) {
console.error(error);
}
}
async function playWhistle() {
if (sound) {
try {
await sound.playAsync();
} catch (error) {
console.error(error);
}
}
}
const endTimer = async () => {
try {
await playWhistle();
setIsActive(false);
} catch (error) {
console.error(error);
}
};
const startCounter = async () => {
await mountSound();
setShouldCount(true);
};
const resetTimer = () => {
if (timeout) {
clearTimeout(timeout);
} else {
timeout = setTimeout(() => {
setRemainingSeconds(timeInSeconds);
clearTimeout(timeout);
}, 1000);
}
};
React.useEffect(() => {
let counterInterval: NodeJS.Timer | undefined = undefined;
if (shouldCount) {
counterInterval = setInterval(() => {
try {
if (counter === 1) {
setCounter((counter) => counter - 1);
}
if (counter > 1) {
playWhistle();
Vibration.vibrate();
setCounter((counter) => counter - 1);
} else {
// Plays the whistle sound and vibrates the device
playWhistle();
Vibration.vibrate();
// Restarts the counter
setCounter(3);
setShouldCount(false);
// Starts the timer
setIsActive(true);
// Stops the counter
clearInterval(counterInterval);
}
} catch (error) {
console.error(error);
}
}, 1000);
} else if (!shouldCount && counter !== 0) {
clearInterval(counterInterval);
}
return () => clearInterval(counterInterval);
}, [shouldCount, counter]);
React.useEffect(() => {
let timerInterval: NodeJS.Timer | undefined = undefined;
if (isActive) {
timerInterval = setInterval(() => {
if (remaningSeconds === 1) {
setRemainingSeconds((remaningSeconds) => remaningSeconds - 1);
}
if (remaningSeconds > 1) {
setRemainingSeconds((remaningSeconds) => remaningSeconds - 1);
} else {
Vibration.vibrate();
endTimer();
resetTimer();
}
}, 1000);
} else if (!isActive && remaningSeconds === 0) {
resetTimer();
clearInterval(timerInterval);
}
return () => clearInterval(timerInterval);
}, [isActive, remaningSeconds]);
React.useEffect(() => {
return sound
? () => {
sound.unloadAsync();
setSound(undefined);
}
: undefined;
}, [sound]);
const parseTime = (time: number) => {
return time < 10 ? `0${time}` : time;
};
return (
<View style={styles.container}>
<StatusBar style="light" />
<Text style={styles.timerText}>{`${parseTime(minutes)}:${parseTime(
seconds
)}`}</Text>
<TouchableOpacity onPress={startCounter} style={styles.button}>
<Text style={styles.buttonText}>{isActive ? "Pause" : "Start"}</Text>
</TouchableOpacity>
</View>
);
};
const styles = StyleSheet.create({
container: {
flex: 1,
backgroundColor: "#07121B",
alignItems: "center",
justifyContent: "center",
},
button: {
borderWidth: 10,
borderColor: "#B9AAFF",
width: screen.width / 2,
height: screen.width / 2,
borderRadius: screen.width / 2,
alignItems: "center",
justifyContent: "center",
},
buttonText: {
color: "#B9AAFF",
fontSize: 20,
},
timerText: {
color: "#fff",
fontSize: 90,
},
});
The issue was that expo-av leaves the audio file at it's end, so the next time you play it, nothing will sound because the file is already over, the way to fix it is pretty simple:
async function playWhistle() {
if (sound) {
try {
await sound.playAsync();
sound.setPositionAsync(0); // ADD THIS LINE
} catch (error) {
console.error(error);
}
}
}
Related
So I have this basic todo:
App.jsx
const ITEMS = [
{ id: 1, text: 'Example 1' },
{ id: 2, text: 'Example 2' },
{ id: 3, text: 'Example 3' }
];
export const App = () => {
const todoRefs = useSharedValue<Record<string, any>>({});
const closeOpenTodos = (id: number) => {
'worklet';
for (const key in todoRefs.value) {
if (Number(key) !== id) {
todoRefs.value[key].closeTodo();
}
}
};
return (
<ScrollView contentContainerStyle={styles.container}>
{ITEMS.map((item, index) => (
<Item key={index} {...{ ...item, todoRefs, closeOpenTodos }} />
))}
</ScrollView>
);
};
Item.jsx (i.e. todo)
const { width: SCREEN_WIDTH } = Dimensions.get('window');
const BUTTON_WIDTH = 100;
const CONTAINER_HEIGHT = 80;
const TRANSLATE_X_THRESHOLD = -SCREEN_WIDTH * 0.7;
type ItemProps = {
id: number;
text: string;
todoRefs: Record<string, any>;
closeOpenTodos: (id: number) => void;
};
type ItemContext = {
translateX: number;
};
export const Item = ({ id, text, todoRefs, closeOpenTodos }: ItemProps) => {
const translateX = useSharedValue(0);
const containerHeight = useSharedValue(CONTAINER_HEIGHT);
const dismissItem = () => {
'worklet';
containerHeight.value = withTiming(0, { duration: 100 });
translateX.value = -SCREEN_WIDTH;
};
todoRefs.value = {
...todoRefs.value,
[id]: {
closeTodo: () => {
'worklet';
translateX.value = withTiming(0);
}
}
};
const panGestureEvent = useAnimatedGestureHandler<
PanGestureHandlerGestureEvent,
ItemContext
>({
onStart: (_event, context) => {
closeOpenTodos(id);
context.translateX = translateX.value;
},
onActive: (event, context) => {
// Prevent swiping to the right
if (event.translationX > 0) {
translateX.value = 0;
return;
}
translateX.value = event.translationX + context.translateX;
},
onEnd: (event, context) => {
// If swiping to the right, close item
if (event.translationX > 0) {
translateX.value = 0;
return;
}
if (event.translationX + context.translateX < TRANSLATE_X_THRESHOLD) {
dismissItem();
return;
}
translateX.value = withSpring(-BUTTON_WIDTH);
}
});
const animatedSliderStyle = useAnimatedStyle(() => {
return {
transform: [{ translateX: translateX.value }]
};
}, []);
const animatedContainerStyle = useAnimatedStyle(() => {
return {
height: containerHeight.value
};
}, []);
return (
<Animated.View style={[styles.container, animatedContainerStyle]}>
<Pressable style={[styles.button]} onPress={() => dismissItem()}>
<Text style={styles.buttonText}>Delete</Text>
</Pressable>
<PanGestureHandler onGestureEvent={panGestureEvent}>
<Animated.View style={[styles.slider, animatedSliderStyle]}>
<Text style={styles.sliderText}>{text}</Text>
</Animated.View>
</PanGestureHandler>
</Animated.View>
);
};
Basically when a todo is swiped open, it reveals a delete button. I want it so that if another todo it swiped open, all others close.
So I'm passing down a todoRefs (which technically aren't "refs") and closeOpenTodos.
All works fine, except this approach has introduced a strange bug.
When I go to delete items, the last one keeps re-appearing.
Is there a better way to do this?
I want to create my own Endomono/Runtastic-like app using RN + expo (This app will be just for me, and I have android phone with pretty decent performance/battery life (Redmi note 7) so I don't worry about performance too much). I wanted to use all-in-one library for that, or just and library that allows me to execute some code each X seconds in background (and getAsyncLocation there). My point is just to send lat/lon data every X seconds to my backend HTTP django-rest-framework powered server.
I just spent whole day trying figure out any way to do that, I tried couple of libraries like this ones: react-native-background-geolocation, react-native-background-timer, react-native-background-job and few more. I followed step by step instalation guide, and I kept getting errors like: null is not an object (evaluating 'RNBackgroundTimer.setTimeout') .
I also tried this: I fixed some errors in this code (imports related), it seemed to work, but when I changed my GPS location using Fake GPS, and only one cast of didFocus functions appears in the console. Here's code:
import React from 'react';
import { EventEmitter } from 'fbemitter';
import { NavigationEvents } from 'react-navigation';
import { AppState, AsyncStorage, Platform, StyleSheet, Text, View, Button } from 'react-native';
import MapView from 'react-native-maps';
import * as Permissions from 'expo-permissions';
import * as Location from 'expo-location';
import * as TaskManager from 'expo-task-manager';
import { FontAwesome, MaterialIcons } from '#expo/vector-icons';
const STORAGE_KEY = 'expo-home-locations';
const LOCATION_UPDATES_TASK = 'location-updates';
const locationEventsEmitter = new EventEmitter();
export default class MapScreen extends React.Component {
static navigationOptions = {
title: 'Background location',
};
mapViewRef = React.createRef();
state = {
accuracy: 4,
isTracking: false,
showsBackgroundLocationIndicator: false,
savedLocations: [],
initialRegion: null,
error: null,
};
didFocus = async () => {
console.log("Hello")
let { status } = await Permissions.askAsync(Permissions.LOCATION);
if (status !== 'granted') {
AppState.addEventListener('change', this.handleAppStateChange);
this.setState({
error:
'Location permissions are required in order to use this feature. You can manually enable them at any time in the "Location Services" section of the Settings app.',
});
return;
} else {
this.setState({ error: null });
}
const { coords } = await Location.getCurrentPositionAsync();
console.log(coords)
const isTracking = await Location.hasStartedLocationUpdatesAsync(LOCATION_UPDATES_TASK);
const task = (await TaskManager.getRegisteredTasksAsync()).find(
({ taskName }) => taskName === LOCATION_UPDATES_TASK
);
const savedLocations = await getSavedLocations();
const accuracy = (task && task.options.accuracy) || this.state.accuracy;
this.eventSubscription = locationEventsEmitter.addListener('update', locations => {
this.setState({ savedLocations: locations });
});
if (!isTracking) {
alert('Click `Start tracking` to start getting location updates.');
}
this.setState({
accuracy,
isTracking,
savedLocations,
initialRegion: {
latitude: coords.latitude,
longitude: coords.longitude,
latitudeDelta: 0.004,
longitudeDelta: 0.002,
},
});
};
handleAppStateChange = nextAppState => {
if (nextAppState !== 'active') {
return;
}
if (this.state.initialRegion) {
AppState.removeEventListener('change', this.handleAppStateChange);
return;
}
this.didFocus();
};
componentWillUnmount() {
if (this.eventSubscription) {
this.eventSubscription.remove();
}
AppState.removeEventListener('change', this.handleAppStateChange);
}
async startLocationUpdates(accuracy = this.state.accuracy) {
await Location.startLocationUpdatesAsync(LOCATION_UPDATES_TASK, {
accuracy,
showsBackgroundLocationIndicator: this.state.showsBackgroundLocationIndicator,
});
if (!this.state.isTracking) {
alert(
'Now you can send app to the background, go somewhere and come back here! You can even terminate the app and it will be woken up when the new significant location change comes out.'
);
}
this.setState({ isTracking: true });
}
async stopLocationUpdates() {
await Location.stopLocationUpdatesAsync(LOCATION_UPDATES_TASK);
this.setState({ isTracking: false });
}
clearLocations = async () => {
await AsyncStorage.setItem(STORAGE_KEY, JSON.stringify([]));
this.setState({ savedLocations: [] });
};
toggleTracking = async () => {
await AsyncStorage.removeItem(STORAGE_KEY);
if (this.state.isTracking) {
await this.stopLocationUpdates();
} else {
await this.startLocationUpdates();
}
this.setState({ savedLocations: [] });
};
onAccuracyChange = () => {
const next = Location.Accuracy[this.state.accuracy + 1];
const accuracy = next ? Location.Accuracy[next] : Location.Accuracy.Lowest;
this.setState({ accuracy });
if (this.state.isTracking) {
// Restart background task with the new accuracy.
this.startLocationUpdates(accuracy);
}
};
toggleLocationIndicator = async () => {
const showsBackgroundLocationIndicator = !this.state.showsBackgroundLocationIndicator;
this.setState({ showsBackgroundLocationIndicator }, async () => {
if (this.state.isTracking) {
await this.startLocationUpdates();
}
});
};
onCenterMap = async () => {
const { coords } = await Location.getCurrentPositionAsync();
const mapView = this.mapViewRef.current;
if (mapView) {
mapView.animateToRegion({
latitude: coords.latitude,
longitude: coords.longitude,
latitudeDelta: 0.004,
longitudeDelta: 0.002,
});
}
};
renderPolyline() {
const { savedLocations } = this.state;
if (savedLocations.length === 0) {
return null;
}
return (
<MapView.Polyline
coordinates={savedLocations}
strokeWidth={3}
strokeColor={"black"}
/>
);
}
render() {
if (this.state.error) {
return <Text style={styles.errorText}>{this.state.error}</Text>;
}
if (!this.state.initialRegion) {
return <NavigationEvents onDidFocus={this.didFocus} />;
}
return (
<View style={styles.screen}>
<MapView
ref={this.mapViewRef}
style={styles.mapView}
initialRegion={this.state.initialRegion}
showsUserLocation>
{this.renderPolyline()}
</MapView>
<View style={styles.buttons} pointerEvents="box-none">
<View style={styles.topButtons}>
<View style={styles.buttonsColumn}>
{Platform.OS === 'android' ? null : (
<Button style={styles.button} onPress={this.toggleLocationIndicator} title="background/indicator">
<Text>{this.state.showsBackgroundLocationIndicator ? 'Hide' : 'Show'}</Text>
<Text> background </Text>
<FontAwesome name="location-arrow" size={20} color="white" />
<Text> indicator</Text>
</Button>
)}
</View>
<View style={styles.buttonsColumn}>
<Button style={styles.button} onPress={this.onCenterMap} title="my location">
<MaterialIcons name="my-location" size={20} color="white" />
</Button>
</View>
</View>
<View style={styles.bottomButtons}>
<Button style={styles.button} onPress={this.clearLocations} title="clear locations">
Clear locations
</Button>
<Button style={styles.button} onPress={this.toggleTracking} title="start-stop tracking">
{this.state.isTracking ? 'Stop tracking' : 'Start tracking'}
</Button>
</View>
</View>
</View>
);
}
}
async function getSavedLocations() {
try {
const item = await AsyncStorage.getItem(STORAGE_KEY);
return item ? JSON.parse(item) : [];
} catch (e) {
return [];
}
}
if (Platform.OS !== 'android') {
TaskManager.defineTask(LOCATION_UPDATES_TASK, async ({ data: { locations } }) => {
if (locations && locations.length > 0) {
const savedLocations = await getSavedLocations();
const newLocations = locations.map(({ coords }) => ({
latitude: coords.latitude,
longitude: coords.longitude,
}));
savedLocations.push(...newLocations);
await AsyncStorage.setItem(STORAGE_KEY, JSON.stringify(savedLocations));
locationEventsEmitter.emit('update', savedLocations);
}
});
}
const styles = StyleSheet.create({
screen: {
flex: 1,
},
mapView: {
flex: 1,
},
buttons: {
flex: 1,
flexDirection: 'column',
justifyContent: 'space-between',
padding: 10,
position: 'absolute',
top: 0,
right: 0,
bottom: 0,
left: 0,
},
topButtons: {
flexDirection: 'row',
justifyContent: 'space-between',
},
bottomButtons: {
flexDirection: 'column',
alignItems: 'flex-end',
},
buttonsColumn: {
flexDirection: 'column',
alignItems: 'flex-start',
},
button: {
paddingVertical: 5,
paddingHorizontal: 10,
marginVertical: 5,
},
errorText: {
fontSize: 15,
color: 'rgba(0,0,0,0.7)',
margin: 20,
},
});
If you know any way to easily complete my target (of sending simple HTTP GET with location from background of Expo + RN app to my DRF backend) please let me know.
If you're using Expo you can simply use expo-task-manager and expo-location to get background location updates.
Here's a simplified version that I'm using (and it's working for sure on Android) on the App I'm currently developing:
import * as Location from 'expo-location';
import * as TaskManager from 'expo-task-manager';
import axios from 'axios';
const TASK_FETCH_LOCATION = 'TASK_FETCH_LOCATION';
// 1 define the task passing its name and a callback that will be called whenever the location changes
TaskManager.defineTask(TASK_FETCH_LOCATION, async ({ data: { locations }, error }) => {
if (error) {
console.error(error);
return;
}
const [location] = locations;
try {
const url = `https://<your-api-endpoint>`;
await axios.post(url, { location }); // you should use post instead of get to persist data on the backend
} catch (err) {
console.error(err);
}
});
// 2 start the task
Location.startLocationUpdatesAsync(TASK_FETCH_LOCATION, {
accuracy: Location.Accuracy.Highest,
distanceInterval: 1, // minimum change (in meters) betweens updates
deferredUpdatesInterval: 1000, // minimum interval (in milliseconds) between updates
// foregroundService is how you get the task to be updated as often as would be if the app was open
foregroundService: {
notificationTitle: 'Using your location',
notificationBody: 'To turn off, go back to the app and switch something off.',
},
});
// 3 when you're done, stop it
Location.hasStartedLocationUpdatesAsync(TASK_FETCH_LOCATION).then((value) => {
if (value) {
Location.stopLocationUpdatesAsync(TASK_FETCH_LOCATION);
}
});
It doesn't necessarily work with Expo, but if "eject" your project or start with the React Native CLI (via react-native init) then you could use an Android specific React Native "NativeModule" to accomplish your goal. I like using the react-native-location package, which has great support on iOS for background location updates, but on Android there is a bug currently. I put together an example project which has the necessary Android specific code inside a NativeModule you could use to start from:
https://github.com/andersryanc/ReactNative-LocationSample
I'm using Expo together with react-native-maps for a rather simple map component. It works fine on iOS, however on Android I get the following error:
abi30_0_0.com.facebook.react.bridge.ReadableNativeMap cannot be cast to java.lang.String
getString
ReadableNativeMap.java:168
showAlert
DialogModule.java:247
invoke
Method.java
invoke
JavaMethodWrapper.java:372
invoke
JavaModuleWrapper.java:160
run
NativeRunnable.java
handleCallback
Handler.java:790
dispatchMessage
Handler.java:99
dispatchMessage
MessageQueueThreadHandler.java:29
loop
Looper.java:164
run
MessageQueueThreadImpl.java:192
run
Thread.java:764
Here is my map component (sorry it's a bit longer):
import React from 'react';
import {
StyleSheet,
View,
Dimensions,
Alert,
TouchableOpacity,
Text,
Platform,
} from 'react-native';
import {
MapView,
Location,
Permissions,
Constants,
} from 'expo';
import { Ionicons } from '#expo/vector-icons';
import axios from 'axios';
import geolib from 'geolib';
import Polyline from '#mapbox/polyline';
import api from '../helpers/api';
import appConfig from '../app.json';
const { width, height } = Dimensions.get('window');
class MapScreen extends React.Component {
static navigationOptions = {
title: 'Map',
};
constructor(props) {
super(props);
this.state = {
coordinates: [],
focusedLocation: {
latitude: 0,
longitude: 0,
latitudeDelta: 0.0122,
longitudeDelta: width / height * 0.0122,
},
destinationReached: false,
isMapReady: false,
};
this.apikey = appConfig.expo.android.config.googleMaps.apiKey;
// bind this in constructor so state can be set in these methods
this.getLocation = this.getLocation.bind(this);
this.getDirections = this.getDirections.bind(this);
this.checkUserLocation = this.checkUserLocation.bind(this);
this.animateToCoordinates = this.animateToCoordinates.bind(this);
}
async componentDidMount() {
// ask the user for location permission
if (Platform.OS === 'android' && !Constants.isDevice) {
Alert.alert('Warning', 'This will not work on sketch in an android emulator. Try it on your device!');
return;
}
if (await !this.isPermissionGranted(Permissions.LOCATION)) {
Alert.alert('Permission', 'You need to enable location services');
return;
}
// get the current location of the user
// retrieve the destination location where the users shift will start
const [currentLocation, destinationLocation] = await Promise.all([
this.getLocation(),
this.getInterceptionCoords(),
]);
// retrieve a direction between these two points
this.getDirections(currentLocation, destinationLocation);
// monitor the current position of the user
this.watchid = await Location.watchPositionAsync({
enableHighAccuracy: true,
distanceInterval: 1,
}, this.checkUserLocation);
}
componentWillUnmount() {
if (this.watchid) {
this.watchid.remove();
}
}
/**
* retrieve current coordinates and move to them on the map
* assumes that location permission has already been granted
* #returns {Promise<{latitude: (number|*|string), longitude: (number|*|string)}>}
*/
async getLocation() {
// get current position if permission has been granted
const { coords } = await Location.getCurrentPositionAsync({
enableHighAccuracy: true,
});
// initalize map at current position
this.animateToCoordinates(coords);
this.setState(prevState => {
return {
focusedLocation: {
...prevState.focusedLocation,
latitude: coords.latitude,
longitude: coords.longitude,
},
};
});
return {
latitude: coords.latitude,
longitude: coords.longitude,
};
}
/**
* retrieves the coordinates of a route
* route: safety drivers position to the interception point
* #param startLoc
* #param destinationLoc
* #returns {Promise<*>}
*/
async getDirections(startLoc, destinationLoc) {
try {
const response = await axios({
method: 'GET',
url: 'https://maps.googleapis.com/maps/api/directions/json',
params: {
origin: Object.values(startLoc).join(','),
destination: Object.values(destinationLoc).join(','),
key: this.apikey,
},
responseType: 'json',
headers: {},
});
if (response.status !== 200) {
// this will execute the catch block
throw new Error('Fetching the coordinates of the interception point failed');
}
const { data } = response;
if (data.status !== 'OK') {
throw new Error('Determining a route between the two points failed');
}
const points = Polyline.decode(data.routes[0].overview_polyline.points);
const coordinates = points.map(point => {
return {
latitude: point[0],
longitude: point[1],
};
});
this.setState({ coordinates: coordinates });
return coordinates;
} catch (error) {
console.log(error);
Alert.alert('Network error', error);
return error;
}
}
/**
* get the coordinates of the interception point
* #returns {Promise<*>}
*/
async getInterceptionCoords() {
try {
const response = await api.get('/shifts/next');
if (response.status !== 200) {
// this will execute the catch block
throw new Error('Fetching the coordinates of the interception point failed');
}
const { data } = response;
return {
latitude: data.latStart,
longitude: data.longStart,
};
} catch (error) {
console.log(error);
Alert.alert('Network error', error);
return error;
}
}
checkUserLocation(location) {
const { coordinates } = this.state;
const { coords } = location;
if (Platform.OS === 'android') {
// follow the user location
// mapview component handles this for ios devices
this.animateToCoordinates(coords);
}
const destinationCoords = coordinates[coordinates.length - 1];
const distance = geolib.getDistance(coords, destinationCoords);
if (distance <= 20) {
// distance to destination is shorter than 20 metres
// show button so user can confirm arrival
this.setState({ destinationReached: true });
} else {
// remove arrival button in case the user moves away from the destination
this.setState({ destinationReached: false });
}
}
/**
* animate to specified coordinates on the map
* #param coords
*/
animateToCoordinates(coords) {
const { focusedLocation } = this.state;
const { latitude, longitude } = coords;
if (focusedLocation && latitude && longitude) {
this.map.animateToRegion({
...focusedLocation,
latitude: latitude,
longitude: longitude,
});
}
}
renderConfirmalButton() {
const { destinationReached } = this.state;
if (!destinationReached) {
return null;
}
return (
<View style={styles.confirmContainer}>
<TouchableOpacity
style={styles.confirmButton}
onPress={this.onArrivalConfirmed}
>
<View style={styles.drawerItem}>
<Ionicons
name="ios-checkmark-circle-outline"
size={30}
color="#ffffff"
style={styles.drawerItemIcon}
/>
<Text style={styles.buttonText}>Confirm Arrival</Text>
</View>
</TouchableOpacity>
</View>
);
}
isPermissionGranted = async permission => {
const { status } = await Permissions.askAsync(permission);
return (status === 'granted');
};
onArrivalConfirmed = () => {
Alert.alert('Confirmation', 'Arrival confirmed');
};
onMapReady = () => {
this.setState({ isMapReady: true });
};
render() {
const { coordinates, focusedLocation, isMapReady } = this.state;
return (
<View style={styles.container}>
<MapView
style={styles.map}
initialRegion={focusedLocation}
showsUserLocation
followsUserLocation={Platform.OS === 'ios'}
loadingEnabled
ref={map => { this.map = map; }}
onMapReady={() => this.onMapReady()}
>
<MapView.Polyline
coordinates={coordinates}
strokeWidth={3}
strokeColor="blue"
/>
{isMapReady && coordinates.length > 0 && (
<MapView.Marker
coordinate={coordinates[coordinates.length - 1]}
/>
)}
</MapView>
{this.renderConfirmalButton()}
</View>
);
}
}
const styles = StyleSheet.create({
container: {
flex: 1,
backgroundColor: '#fff',
},
map: {
width: width,
height: height,
},
confirmContainer: {
position: 'absolute',
left: 0,
bottom: 0,
height: 150,
width: '100%',
justifyContent: 'center',
},
confirmButton: {
paddingHorizontal: 30,
},
drawerItem: {
flexDirection: 'row',
alignItems: 'center',
justifyContent: 'center',
padding: 10,
backgroundColor: 'lightblue',
borderRadius: 15,
},
drawerItemIcon: {
marginRight: 10,
},
buttonText: {
color: '#ffffff',
fontSize: 22,
},
});
export default MapScreen;
Any help is greatly appreciated!
I want to countdown from 3 to 1 when a screen is loaded in react-native. I tried it with setTimeOut like this and it didn't work. What am I doing wrong here? How can I achieve this? When the screen is loaded, I want to show 3 =-> 2 ==> 1 with 1 second interval. Here is my code.
constructor(props) {
super(props);
this.state = {
timer: 3
}
}
// componentDidMount
componentDidMount() {
setTimeout(() => {
this.setState({
timer: --this.state.timer
})
}, 1000);
}
In your code setTimeout is called in componentDidMount and ComponetDidMount will be called once in whole component lifeCycle. So, the function within setTimeout will be called once only. i.e. just after the first render but upon successive render, the componentDidMount won't be called.
Solution to your problem can be:
1. Class Component
constructor(props: Object) {
super(props);
this.state ={ timer: 3}
}
componentDidMount(){
this.interval = setInterval(
() => this.setState((prevState)=> ({ timer: prevState.timer - 1 })),
1000
);
}
componentDidUpdate(){
if(this.state.timer === 1){
clearInterval(this.interval);
}
}
componentWillUnmount(){
clearInterval(this.interval);
}
render() {
return (
<View style={{ flex: 1, justifyContent: 'center', }}>
<Text> {this.state.timer} </Text>
</View>
)
}
'setInterval' vs 'setTimeout'
Advantage of using a function in setState instead of an object
memory leak because of setInterval:
if we unmount the component before clearInterval called, there is a memory leak because the interval that is set when we start and the timer is not stopped. React provides the componentWillUnmount lifecycle method as an opportunity to clear anything that needs to be cleared when the component is unmounted or removed.
2. Functional Component
function CountDownTimer(props) {
const [time, setTime] = React.useState(props.initialValue || 10);
const timerRef = React.useRef(time);
React.useEffect(() => {
const timerId = setInterval(() => {
timerRef.current -= 1;
if (timerRef.current < 0) {
clearInterval(timerId);
} else {
setTime(timerRef.current);
}
}, 1000);
return () => {
clearInterval(timerId);
};
}, []);
return (
<View style={{ flex: 1, justifyContent: 'center' }}>
<Text> {time} </Text>
</View>
)
}
useRef returns a mutable ref object whose .current property is initialized to the passed argument (initialValue). The returned object will persist for the full lifetime of the component. So on component rerender the object reference will be same.
Answers given by #TheEhsanSarshar and #Rishabh Jain will also work. I have shown a slightly different solution from the others.
Updated Hooks (using useEffect) version to countdown using setInterval in react-native:
const [timerCount, setTimer] = useState(60)
useEffect(() => {
let interval = setInterval(() => {
setTimer(lastTimerCount => {
lastTimerCount <= 1 && clearInterval(interval)
return lastTimerCount - 1
})
}, 1000) //each count lasts for a second
//cleanup the interval on complete
return () => clearInterval(interval)
}, []);
use the state variable timerCount as: <Text>{timerCount}</Text>
Usage:
timestamp prop must be in seconds
const refTimer = useRef();
const timerCallbackFunc = timerFlag => {
// Setting timer flag to finished
console.warn(
'You can alert the user by letting him know that Timer is out.',
);
};
<Timer
ref={refTimer}
timestamp={moment(item?.time_left).diff(moment(), 'seconds')}
timerCallback={timerCallbackFunc}
textStyle={styles.timerTextAHL}
/>
Timer.js
import React, {
useState,
useEffect,
useRef,
forwardRef,
useImperativeHandle,
} from 'react';
import { Text, View } from 'react-native';
const Timer = forwardRef((props, ref) => {
// For Total seconds
const [timeStamp, setTimeStamp] = useState(
props.timestamp ? props.timestamp : 0,
);
// Delay Required
const [delay, setDelay] = useState(props.delay ? props.delay : 1000);
// Flag for informing parent component when timer is over
const [sendOnce, setSendOnce] = useState(true);
// Flag for final display time format
const [finalDisplayTime, setFinalDisplayTime] = useState('');
useInterval(() => {
if (timeStamp > 0) {
setTimeStamp(timeStamp - 1);
} else if (sendOnce) {
if (props.timerCallback) {
props.timerCallback(true);
} else {
console.log('Please pass a callback function...');
}
setSendOnce(false);
}
setFinalDisplayTime(secondsToDhms(timeStamp));
}, delay);
function secondsToDhms(seconds) {
seconds = Number(seconds);
var d = Math.floor(seconds / (3600 * 24));
var h = Math.floor((seconds % (3600 * 24)) / 3600);
var m = Math.floor((seconds % 3600) / 60);
var s = Math.floor(seconds % 60);
var dDisplay = d > 0 ? d + 'd ' : '';
var hDisplay = h > 0 ? h + 'h ' : '';
var mDisplay = m > 0 ? m + 'm ' : '';
var sDisplay = s > 0 ? s + 's ' : '';
return dDisplay + hDisplay + mDisplay + sDisplay;
}
const refTimer = useRef();
useImperativeHandle(ref, () => ({
resetTimer: () => {
// Clearing days, hours, minutes and seconds
// Clearing Timestamp
setTimeStamp(props.timestamp);
setSendOnce(true);
},
}));
return (
<View ref={refTimer} style={props.containerStyle}>
<Text style={props.textStyle}>{sendOnce ? finalDisplayTime : '0'}</Text>
</View>
);
});
function useInterval(callback, delay) {
const savedCallback = useRef();
// Remember the latest function.
useEffect(() => {
savedCallback.current = callback;
}, [callback]);
// Set up the interval.
useEffect(() => {
function tick() {
savedCallback.current();
}
if (delay !== null) {
const id = setInterval(tick, delay);
return () => {
clearInterval(id);
};
}
}, [delay]);
}
export default Timer;
The hooks version.
function CountDown() {
const [count, setCount] = useState(3)
useEffect(() =>
let interval = setInterVal(() => {
setCount(prev => {
if(prev === 1) clearInterval(interval)
return prev - 1
})
})
// interval cleanup on component unmount
return () => clearInterval(interval)
), [])
return <Text>{count}</Text>
}
If anyone wants to start the timer again on a button press, this will be the code in react-hooks:
let timer = () => {};
const myTimer = () => {
const [timeLeft, setTimeLeft] = useState(30);
const startTimer = () => {
timer = setTimeout(() => {
if(timeLeft <= 0){
clearTimeout(timer);
return false;
}
setTimeLeft(timeLeft-1);
}, 1000)
}
useEffect(() => {
startTimer();
return () => clearTimeout(timer);
});
const start = () => {
setTimeLeft(30);
clearTimeout(timer);
startTimer();
}
return (
<View style={styles.container}>
<Text style={styles.timer}>{timeLeft}</Text>
<Button onPress={start} title="Press"/>
</View>
)}
Here in this example, I have taken a timer of 30 seconds
Code Of Power
Hope so this Way is Easy
componentDidMount() {
this.CounterInterval()
}
CounterInterval = () => {
this.interval = setInterval(
() => this.setState({
timer: this.state.timer - 1
}, () => {
if (this.state.timer === 0) {
clearInterval(this.interval);
}
}),
1000
);
}
How to remove network request failed error screen and display message "No internet connection" for better user experience in react-native when there is no internet connection.
You can use NetInfo in React-Native to check network state. This is link:
https://facebook.github.io/react-native/docs/netinfo.html
This is example code:
NetInfo.getConnectionInfo().then((connectionInfo) => {
if (connectionInfo.type === 'none') {
alert("No internet connection")
} else {
// online
// do something
}
});
Here i wrote an component for handling internet status issues refer this:
import React, { Component } from "react";
import {
View,
NetInfo,
Animated,
Easing,
Dimensions,
Platform,
AppState
} from "react-native";
// import { colors, Typography, primaryFont } from "../../Config/StylesConfig";
import { connect } from "react-redux";
import { changeConnectionStatus } from "../../actions/authActions";
import CustomText from "./CustomText";
import firebaseHelper from "../../helpers/firebaseHelper";
const { width } = Dimensions.get("window");
class InternetStatusBar extends Component {
constructor(props) {
super(props);
this.state = {
isNetworkConnected: true
};
this._updateConnectionStatus = this._updateConnectionStatus.bind(this);
this.positionValue = new Animated.Value(-26);
this.colorValue = new Animated.Value(0);
this.isMount = true;
this.isOnline = true;
}
_handleAppStateChange = nextAppState => {
if (nextAppState.match(/inactive|background/) && this.isOnline) {
firebaseHelper.goOffline();
// console.log("offline");
this.isOnline = false;
} else if (nextAppState === "active" && this.isOnline === false) {
firebaseHelper.goOnline();
// console.log("online");
this.isOnline = true;
}
};
componentDidMount() {
AppState.addEventListener("change", this._handleAppStateChange);
// NetInfo.isConnected.fetch().done(isNetworkConnected => {
// this._updateConnectionStatus(isNetworkConnected);
// });
NetInfo.isConnected.addEventListener(
"connectionChange",
this._updateConnectionStatus
);
}
componentWillUnmount() {
AppState.removeEventListener("change", this._handleAppStateChange);
NetInfo.isConnected.removeEventListener(
"connectionChange",
this._updateConnectionStatus
);
}
_updateConnectionStatus(isNetworkConnected) {
// this.setState({ isNetworkConnected });
if (this.isMount) {
this.isMount = false;
} else {
if (isNetworkConnected) {
this.animateColorChange(isNetworkConnected);
setTimeout(() => {
this.animateErrorView(isNetworkConnected);
}, 1000);
} else {
this.animateErrorView(isNetworkConnected);
this.colorValue = new Animated.Value(0);
}
}
// this.props.changeConnectionStatus(isNetworkConnected);
}
// componentWillReceiveProps = nextProps => {
// if (
// nextProps.isInternetConnected &&
// nextProps.isInternetConnected != this.state.isInternetConnected
// ) {
// const date = new Date();
// Actions.refresh({ refreshContent: date.getTime() });
// }
// };
animateErrorView(connected) {
Animated.timing(this.positionValue, {
toValue: connected ? -40 : Platform.OS === "ios" ? 20 : 0,
easing: Easing.linear,
duration: 600
}).start();
}
animateColorChange(connected) {
Animated.timing(this.colorValue, {
toValue: connected ? 150 : 0,
duration: 800
}).start();
}
render() {
return (
<Animated.View
style={[
{
position: "absolute",
backgroundColor: this.colorValue.interpolate({
inputRange: [0, 150],
outputRange: ["rgba(0,0,0,0.6)", "rgba(75, 181, 67, 0.8)"]
}),
zIndex: 1,
width: width,
top: 0,
transform: [{ translateY: this.positionValue }]
}
]}
>
<View
style={[
{
padding: 4,
flexDirection: "row",
flex: 1
}
]}
>
<CustomText
style={{
fontSize: 12,
textAlign: "center",
flex: 1
}}
>
{this.state.isInternetConnected ? "Back online" : "No connection"}
</CustomText>
</View>
</Animated.View>
);
}
}
const mapStateToProps = state => {
return {
isInternetConnected: state.user.isInternetConnected
};
};
export default connect(mapStateToProps, { changeConnectionStatus })(
InternetStatusBar
);
A Snackbar is a good way to convey this. Have a look at this library :
https://github.com/9gag-open-source/react-native-snackbar-dialog
Easy and Simple with good user experience
use "react-native-offline-status"
Reference:
https://github.com/rgabs/react-native-offline-status