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 :(
Related
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
I am struggling a little with getting in app purchases working due to lack of examples that show how all the functionality links together
In my app, I have one in app purchase which basically allows the user to unlock some restricted functionality for life.
So at the start I want to check if the user have purchased the item before. (via get history)
If they have I unlock the functionality.
On my signed APK file (android) made in android studio, I have the following issues:
-the purchase never acknowledges (although it does when run via react-native run-android)
-if you press the purchase button twice the error "already connected to app store appears"
-I don't think its getting the purchase history when running from the signed file (although I can print out the result in the console in debug mode)
I am not entirely sure when to call await InAppPurchases.connectAsync(); so this could be one potential source of issues
So this is my code in my "Inner App" . My App component is just the InnerApp wrapped in the provider component from redux. The inner app contains all the navigation stacks so the purchase listener should be global.
e.g.
export default function App (){
...more code
return(
< Provider store={store} >
< InnerApp />
</ Provider >
}
Inner app code
import * as InAppPurchases from 'expo-in-app-purchases';
export default function InnerApp (){
.....some more code
//gets purchase history
const getHistory = async ()=>{
await InAppPurchases.connectAsync();
let found=false
const { responseCode, results } = await InAppPurchases.getPurchaseHistoryAsync();
if (responseCode === InAppPurchases.IAPResponseCode.OK) {
results.forEach(result => {
if (result.acknowledged) {
found =true
// this is just saving to local storage (in case they are using the app offline)
savePurchaseHistory(true)
}else{
savePurchaseHistory(false)
}
});
}
if( found){
//updates a state in the redux store
dispatch(purchaseIAP() )
}else if(responseCode === IAPResponseCode.USER_CANCELED ){
dispatch(removeIAP() )
savePurchaseHistory(false)
}
await InAppPurchases.disconnectAsync();
}
//listens for purchases
const setUpIAP = async() => {
// Set purchase listener
await InAppPurchases.connectAsync();
await InAppPurchases.setPurchaseListener(({ responseCode, results, errorCode }) => {
// Purchase was successful
if (responseCode === InAppPurchases.IAPResponseCode.OK) {
results.forEach(purchase => {
if (!purchase.acknowledged) {
// Process transaction here and unlock content...
dispatch(purchaseIAP() )
// Then when you're done
InAppPurchases.finishTransactionAsync(purchase, false);
}
});
}
// Else find out what went wrong
if (responseCode === InAppPurchases.IAPResponseCode.USER_CANCELED) {
} else if (responseCode === InAppPurchases.IAPResponseCode.DEFERRED) {
console.log('User does not have permissions to buy but requested parental approval (iOS only)');
} else {
console.warn(`Something went wrong with the purchase. Received errorCode ${errorCode}`);
}
});
}
//The in app stuff is called when the component is mounted
useEffect(() => {
setUpIAP()
getHistory()
}, [ ] })
Further in my app I have a button that calls the following function when pressed
const unlockModes = async () => {
try {
const items = Platform.select({
ios: [
'dev.products.all_modes'
],
android: ['all_modes'],
});
await connectAsync();
const products = await InAppPurchases.getProductsAsync(items);
if (products.results.length > 0) {
await InAppPurchases.purchaseItemAsync("all_modes");
}
} catch (err) {
alert("error occured while trying to purchase: " + err);
}
};
In the end I used the React Native IAP library and I couldn't get the expo one to work.
I think the Expo Version currently might just be bust.
Setting useGooglePlayCache will resolve your problem
I am using AsyncStorage.getItem in React Native.
As soon as the Application loads, I want to get the saved data in the device memory using AsyncStorage.getItem. I thought of using ComponentDidMount(). So as soon as the components are loaded, I want to run the AsyncStorage.getItem automatically and save the data to the array DATA. This way the user will not push any button to start rendering what is saved on the memory of the device.
I used the code below, but I do not see any console.log activity. But the console.log works on my other pages on same program here. It seems the ComponentDidMount() did not get executed.
Thanks!
componentDidMount(){
async () => {
try {
const HomeData = await AsyncStorage.getItem('#MyApp_Homekey')
return HomeData
} catch (e) {
console.log('There was error.')
}
if(!HomeData){
console.log('There are no Dimmer Light saved in the memory.')
}
else {
console.log('There is value in data after getItem.')
this.setState(DATA = HomeData)
}
}
As metioned in comment you should use async for componentDidMount as:-
componentDidMount = async () => {
const HomeData = await AsyncStorage.getItem('#MyApp_Homekey')
if(!HomeData){
console.log('There are no Dimmer Light saved in the memory.')
}
else {
console.log('There is value in data after getItem.')
this.setState(DATA = HomeData)
}
}
I have a user preferences screen in my app in which data is managed using asyncStorage. Whenever I change some value in preferences, I need to reflect that change in other screens of the app. But it does not show changes immediately but shows them when I reload the app. What should I do ..?
I am fetching data using: multiGet() in ComponentWillMount() and ComponentDidMount() and transitioning between screens with drawerNavigation.
I have even tried to use a global variable to reflect the changes but I does not help. Should I use redux? What should I do ? Thanks in advance.
use async-await to fetch data from asyncStorage
like this
_retrieveData = async () => {
try {
const value = await AsyncStorage.getItem('TASKS');
if (value !== null) {
// update your ui
console.log(value);
}
} catch (error) {
// Error retrieving data
}
};
when I press physical return button on my phone the log have no output until back root route
componentWillMount(){
BackHandler.addEventListener('hardwareBackPress', this._onBackAndroid)
}
_onBackAndroid = () => {
console.log(this.props.navigation.state.routeName)
if (this.lastBackPressed && this.lastBackPressed + 2000 >= Date.now()) {
return false;
}
this.lastBackPressed = Date.now();
toastShort('Press Again Exit App');
return true;
};
componentWillUnmount(){
BackHandler.removeEventListener('hardwareBackPress', this._onBackAndroid)
}
By design, react-navigation takes full control of the back button unless you handle the state yourself (by using something like Redux).
You can take a look at this issue, which is referencing a similar situation.