I am writing an app with Expo that uses expo-location to track the location of a user in the background. I would like to use hooks (states, useEffect...) when my app is in the background. At the moment the background tracking code looks like that
export default function BackgroundLocationHook() {
[...]
const [position, setPosition] = useState(null);
const [newLocation, setNewLocation] = useState(null) ;
TaskManager.defineTask(LOCATION_TASK_NAME, async ({ data, error }) => {
if (error) {
console.error(error);
return;
}
if (data) {
// Extract location coordinates from data
const { locations } = data;
const location = locations[0];
if (location) {
console.log("Location in background", location.coords);
}
}
setPosition(location.coords);
});
[...]
return [position];
}
But it is a bit hacky as the geolocation_tracking task shares some states with the
I would also like to play some sounds when I am close to a some location even when my app is in the background. I plan to do it with useEffect like that:
useEffect(() => {
const requestPermissions = async () => {
if(shouldPlaySound(newLocation)){
playSound()
}
};
requestPermissions();
}, [newLocation]);
This works when my app is in the foreground but I heard that react hooks such as states, and useEffect do not work when the app is in the background. So my question is what is the alternative to make sure I still have a sound being played when my app is in the background and if it is possible to have hooks working even when the app is in the background.
I see you want to perform some task in the background when you pass a specific location,
With the expo location, we can achieve this implementation.
You can add fencing to your desired location and when the device will enter the fencing area or exits from the fencing area you will get an event to handle some tasks and you are also able to listen to the event in the background with the Expo Task manager.
You need to follow the steps to achieve this.
Define a task using Expo Task Manager outside the react life cycle,
and read the official documentation for API usage. Expo Task Manager
Take the necessary permissions to access the location in the background, and start geofencing with your component. Expo Location
Stop the fencing listener using stopGeofencingAsync from expo-location when it is not needed anymore.
Now you will get events every time you enter or exit from the specified location in startGeofencingAsync until you stop using the stopGeofencingAsync method.
Hope this will help you achieve your desired input.
to run a task in the background you can check any of these library.
react-native-background-actions
react-native-background-timer
this is some example code
import BackgroundTimer from 'react-native-background-timer';
// Start a timer that runs continuous after X milliseconds
const intervalId = BackgroundTimer.setInterval(() => {
// this will be executed every 200 ms
// even when app is the background
console.log('tic');
}, 200);
// Cancel the timer when you are done with it
BackgroundTimer.clearInterval(intervalId);
// Start a timer that runs once after X milliseconds
const timeoutId = BackgroundTimer.setTimeout(() => {
// this will be executed once after 10 seconds
// even when app is the background
console.log('tac');
}, 10000);
// Cancel the timeout if necessary
BackgroundTimer.clearTimeout(timeoutId);
this is another example of this code
import BackgroundService from 'react-native-background-actions';
const sleep = (time) => new Promise((resolve) => setTimeout(() => resolve(), time));
// You can do anything in your task such as network requests, timers and so on,
// as long as it doesn't touch UI. Once your task completes (i.e. the promise is resolved),
// React Native will go into "paused" mode (unless there are other tasks running,
// or there is a foreground app).
const veryIntensiveTask = async (taskDataArguments) => {
// Example of an infinite loop task
const { delay } = taskDataArguments;
await new Promise( async (resolve) => {
for (let i = 0; BackgroundService.isRunning(); i++) {
console.log(i);
await sleep(delay);
}
});
};
const options = {
taskName: 'Example',
taskTitle: 'ExampleTask title',
taskDesc: 'ExampleTask description',
taskIcon: {
name: 'ic_launcher',
type: 'mipmap',
},
color: '#ff00ff',
linkingURI: 'yourSchemeHere://chat/jane', // See Deep Linking for more info
parameters: {
delay: 1000,
},
};
await BackgroundService.start(veryIntensiveTask, options);
await BackgroundService.updateNotification({taskDesc: 'New ExampleTask description'}); // Only Android, iOS will ignore this call
// iOS will also run everything here in the background until .stop() is called
await BackgroundService.stop();
A third solution for android is the headlessjs that only works on android
you can tak help from this
Related
I am using react native to make an app. I made an app that downloads manga books and views them when I start downloading it shows a progress bar which works fine but if I move to another page and come back to the downloading page I don't see the progress bar but the downloading is still going on in the background. I got a suggestion to use redux. I used redux and I modify the store whenever the downloading percentage changes but it causes my app to not respond. I am stuck here. what I do now.
Note: I am using the pure component.
here is the reducer code
const initailstate = {};
const reducerfunc = (state = initailstate, action) => {
switch (action.type) {
case "setpercentage":
state = { ...state };
state[action.manganame] == undefined
? (state[action.manganame] = {})
: null;
state[action.manganame][action.indexid] = {
chaptername: action.chaptername,
percentage: action.percentage,
manganame: action.manganame,
};
return state;
default:
console.log(state);
return state;
}
};
export default reducerfunc;
Here is the progress bar callback where I am dispatching it
callback = async (downloadProgress) => {
try {
if (Math.sign(downloadProgress.totalBytesExpectedToWrite) == 1) {
const progress = parseInt(
(downloadProgress.totalBytesWritten /
downloadProgress.totalBytesExpectedToWrite) *
100
);
this.props.dispatchsetpercentage({
type: "setpercentage",
percentage: progress,
indexid: this.indexofchapter,
chaptername: this.chaptername,
manganame: this.details.name,
});
} else {
}
} catch (e) {
console.log("error of callback " + e.message);
}
};
I think my UI stopped responding because it updates a lot of time and the app re-renders a lot of time
IS there any way to store the progress percentage globally and show it whenever the user comes back to the downloading page?
I want just like youtube or any other app which downloads things
they show the progress whenever we come back to the download page.
please help me :(
i am getting this error mutiple time
You started loading the font "Poppins_400Regular", but used it before it finished loading. You need to wait for Font.loadAsync to complete before using the font.
when run the code
In your apps entry point, usually App.jsx you can render null or a loading state whilst the fonts for your app load, and then once the loadAsync finishes you render your app, something along the lines of:
// App.jsx, or whatever your entry point is
const App = () => {
const [fontLoaded, setFontLoaded] = React.useState(false)
React.useEffect(() => {
Font.loadAsync({
"Poppins_400Regular": require("../path/to/your/font"),
})
.then(() => {
setFontLoaded(true)
})
}, [])
if (!fontLoaded) return null
return (
// All of your normal app ui
)
}
I am using plugin
https://github.com/seididieci/capacitor-backround-geolocation
to watch the user's location. then I am tracking that location with the help of a pusher. this background location works only for 5 minutes after that it just stops. I am using Capacitor's Background task. But that plugin also keeps data on phone after the user opens the app. the Background task sends data to the pusher.
Here is watch location function
getLocation: async function () {
BackgroundGeolocation.initialize({
notificationText: "Your app is running, tap to open.",
notificationTitle: "App Running",
updateInterval: 10000,
requestedAccuracy: BgGeolocationAccuracy.HIGH_ACCURACY,
// Small icon has to be in 'drawable' resources of your app
// if you does not provide one (or it is not found) a fallback icon will be used.
smallIcon: "ic_small_icon",
// Start getting location updates right away. You can set this to false or not set at all (se below).
startImmediately: true,
});
// const geolocation = new Geolocation.Geolocation();
BackgroundGeolocation.addListener("onLocation", (location) => {
// console.log("Got new location", location);
this.subscribe(location.longitude, location.latitude);
console.log(location)
});
BackgroundGeolocation.addListener("onPermissions", (location) => {
// console.log("BGLocation permissions:", location);
this.subscribe(location.longitude, location.latitude);
// Do something with data
});
BackgroundGeolocation.start();
},
Then calling function in mounted()
mounted(){
this.getLocation
App.addListener("appStateChange", (state) => {
setInterval(this.getLocation, 120000);
if (!state.isActive) {
BackgroundTask.beforeExit(async () => {
setInterval(this.getLocation, 120000);
console.og('Why')
});
}
if (state.isActive) {
setInterval(this.getLocation, 120000);
console.log('Active')
}
});
}
You need to use https://ionicframework.com/docs/native/foreground-service like this for running the background.
I am trying to sync data capture offline with an online api, I periodically run an background task using react-native-background-task to retrieve offline data and sync the data with an online api.
react-native-background-task error
// This component below triggers the background task on load
import { sync, clean } from "../../services/market/forms/tasks";
import MediaWorker from "../../services/market/forms/MediaWorker";
let worker = new MediaWorker();
BackgroundTask.define(async () => {
console.log("Life's good");
// loads data from db and sync them with the online service
await sync(worker);
// delete synced data from the db and end task
await clean();
});
export default class Onboard extends Component {
constructor(props) {
super(props);
}
async checkStatus() {
const status = await BackgroundTask.statusAsync();
if (status.available) {
// schedule the background task
BackgroundTask.schedule();
return;
}
const reason = status.unavailableReason;
if (reason === BackgroundTask.UNAVAILABLE_DENIED) {
Alert.alert(
"Denied",
'Please enable background "Background App Refresh" for this app'
);
} else if (reason === BackgroundTask.UNAVAILABLE_RESTRICTED) {
Alert.alert(
"Restricted",
"Background tasks are restricted on your device"
);
}
}
componentDidMount() {
this.checkStatus();
}
render() {
// Not important for the question
}
}
// snippet for sync function
export const sync = async worker => {
const formInstances = await loadFormInstance();
if (formInstances.length) {
// Send Textual data
const formInstancesText = filterFormInstances(formInstances, "text");
postFormTextInstance(formInstancesText);
// Get form image data and post
const formInstancesImage = filterFormInstances(formInstances, "image");
formInstancesImage.forEach(worker.send);
// Get form audio data and post
const formInstancesAudio = filterFormInstances(formInstances, "audio");
formInstancesAudio.forEach(worker.send);
// Get form video data and post
const formInstancesVideo = filterFormInstances(formInstances, "video");
formInstancesVideo.forEach(worker.send);
} else {
console.log("Nothing to sync");
BackgroundTask.finish();
}
};
// snippet for clean function
export const clean = async () => {
const formInstances = await loadFormInstance();
if (formInstances.length) {
const toBeDeleted = new Set();
formInstances.forEach(formInstance => {
const fields = formInstance.fields;
let allSynced = true;
for (let index in fields) {
const field = fields[index];
if (field.synced === false) {
allSynced = false;
break;
}
}
if (allSynced) {
toBeDeleted.add(formInstance.instanceID);
}
});
toBeDeleted.forEach(deleteFormInstance);
} else {
console.log("All tasks finished");
BackgroundTask.finish();
}
};
Adb log(Used for monitoring background activity)
Note: Background task runs successfully a lot of time, but fails occasionally with the red screen shown when the app is build in debug mode.
In release mode, the app completely crashes.
Stack trace generated by Crashlytics in production
I fixed it, it turned out react-native-background-task version wasn't compatible with my react-native version, i upgraded from 0.48.1 to 0.51.0 which requires react 16.0.0
reading from the expo docs:
For iOS, you would be wise to handle push notifications that are
received while the app is foregrounded, because otherwise the user
will never see them. Notifications that arrive while the app are
foregrounded on iOS do not show up in the system notification list. A
common solution is to just show the notification manually. For
example, if you get a message on Messenger for iOS, have the app
foregrounded, but do not have that conversation open, you will see the
notification slide down from the top of the screen with a custom
notification UI.
What I don't understand is what is the best approach for that? is there an Expo API for showing such messages? or should I create an alert component of my own? It is not really clear from the docs.
Thanks.
This answer is outdated as of February 20, 2020. Please see https://stackoverflow.com/a/60344280/2441420 for how to show iOS Notification when your application is in the Foreground
There isn't an Expo API for showing those messages. You can use any 'toast' library of your choosing and display the notification message, but that should be all your code.
For example, this is how we are doing right now:
export default class HomeScreen extends React.Component {
componentDidMount() {
this.notificationSubscription = Notifications.addListener(
(notification) => this.handlePushNotification(notification),
);
}
handlePushNotification(notification) {
const { navigation } = this.props;
PushNotificationsService.handleNotification(notification, navigation);
}
(...)
import Toast from 'react-native-root-toast';
export default class PushNotificationsService {
static handleNotification(notification, navigation) {
if (notification.data.screen && notification.origin === 'selected') {
navigation.navigate(notification.data.screen);
}
Toast.show(notification.data.message);
}
}
Toast libraries include:
react-native-root-toast
react-native-easy-toast
react-native-simple-toast
Now you can just add that in one of your app entry point. The shouldShowAlert is what you want here
import * as Notifications from 'expo-notifications';
Notifications.setNotificationHandler({
handleNotification: async () => ({
shouldShowAlert: true,
shouldPlaySound: false,
shouldSetBadge: false,
}),
});
App.json :
{
"expo": {
"notification": {
"iosDisplayInForeground": true
}
}
DEMO
I'm not sure exactly when this was added to Expo, but as of Expo version 36 is easily doable.
To show Expo Push Notifications on iOS when your app is in the foreground, please do the following:
import { Vibration } from "react-native";
import { Notifications } from "expo";
import * as Permissions from "expo-permissions";
import Constants from "expo-constants";
registerForPushNotificationsAsync = async () => {
if (Constants.isDevice) {
const { status: existingStatus } = await Permissions.getAsync(
Permissions.NOTIFICATIONS
);
let finalStatus = existingStatus;
if (existingStatus !== "granted") {
const { status } = await Permissions.askAsync(
Permissions.NOTIFICATIONS
);
finalStatus = status;
}
if (finalStatus !== "granted") {
alert("Failed to get push token for push notification!");
return;
}
let token = await Notifications.getExpoPushTokenAsync();
console.log("Go to https://expo.io/notifications and copy the token below to easily send yourself a notification.");
console.warn("Notifications on iOS (and I believe Android) ONLY WORK ON A PHYSICAL DEVICE, not a simulator or emulator!!!")
console.log(token);
this.setState({ expoPushToken: token });
} else {
alert("Must use physical device for Push Notifications");
}
};
componentDidMount() {
this.registerForPushNotificationsAsync();
this._notificationSubscription = Notifications.addListener(
this._handleNotification
);
}
_handleNotification = async notification => {
if (notification.remote) {
Vibration.vibrate();
const notificationId = Notifications.presentLocalNotificationAsync({
title: "Follow #technoplato",
body: "To learn yourself goodly (also follow PewDiePie)",
ios: { _displayInForeground: true } // <-- HERE'S WHERE THE MAGIC HAPPENS
});
}
};
Quick and Easy Sanity Check
1) Go here: https://expo.io/notifications
2) Copy the token that is output to the terminal when your application is run.
3) Open your application on iOS.
4) Send a notification to yourself from https://expo.io/notifications and observe that it shows up even when your app is foregrounded.
Notes
Notifications WILL NOT BE RECEIVED ON AN IOS SIMULATOR
Expo makes Notifications ridiculously easy. I honestly can't believe it.
No idea why displayInForeground is false by default and not more prominent in the documentation. I'll submit a PR for it if I can.
Code originally found at this Snack: https://snack.expo.io/#documentation/pushnotifications?platform=ios
LocalNotification.ios._displayInForeground found here: https://docs.expo.io/versions/v36.0.0/sdk/notifications/#localnotification