react-native-background-actions prevent the app from closing by user on Android 10

[alexfov]

Hello and thank you for such a nice library. I faced a problem on Android. When I use background task, and then close my app it doesn't closes actually despite it is absent in the opened apps list. When I open the app again it starts with the last state that was before closing.

import React, { useEffect } from 'react';
import { Text, View, StyleSheet } from 'react-native';
import SplashScreen from 'react-native-splash-screen';
import BackgroundService from 'react-native-background-actions';

const sleep = (time) => new Promise((resolve) => setTimeout(() => resolve(), time));

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,
  },
};

let i = 0;
export default function App() {
  useEffect(() => {
    SplashScreen.hide();
  }, []);

  useEffect(() => {
    BackgroundService.start(veryIntensiveTask, options);
    return () => {
      BackgroundService.stop();
    };
  }, []);

  useEffect(() => {
    i++;
    console.log({ i });
  }, []);

  return (
    <View style={st.container}>
      <Text />
    </View>
  );
}

const st = StyleSheet.create({
  container: { flex: 1 },
});

On first open I see i = 1. Then I close the app and open it again and see i = 2, then i = 3 etc... This leads to several time redux-saga initialization and multiple queries.

"react-native": "^0.64.2", "react": "^17.0.2", "react-native-background-actions": "^2.6.5",

Android 9, 10 BlackView 5900, Xiaomi Redmi Note 7

[clgh0331]

i have same issue..

[clgh0331]

I sorved this problem if (!BackgroundService.isRunning()) { await BackgroundService.start(veryIntensiveTask, options); }

[alexfov]

It doesn't help for me. As workaround I use this:

useLayoutEffect(() => {
    i++;
    console.log({ i });
    if (i > 1) CodePush.restartApp();
  }, []);

[clgh0331]

Sorry, I misunderstood. But, I don't have such issues

[Rapsssito]

@alexfov, this is the expected behavior. However, I believe React Native allows you to listen for app state changes, so you can close the task when the app is being closed.

[alexfov]

@Rapsssito as you can see in the 1st post I use stop() method inside useEffect. If I add log to the promise result I can see that task is stopped. Also I added BackgroudService.isRunning() before starting task and it says that there is no active task. And notification disappears when the app is closed. So I can infer that there is no background tasks when app is closed.

[Rapsssito]

@alexfov, the issue is that when you open the app, it starts counting from when it stopped?

[alexfov]

@alexfov, the issue is that when you open the app, it starts counting from when it stopped?

Not counting itself. The issue is several times redux-saga initialization. So when I dispatch an action that makes a network request I get multiple queries. It is the first issue that I noticed. I'm sure there are others.

App opened 1st time - normal behavior, 1 dispatch - 1 query. App opened 2nd time - 1 dispatch - 2 queries. App opened 3rd time - 1 dispatch - 3 queries. And so on.

It is strange, because I haven't active background actions when app is closed. Log says that task is terminated.

useEffect(() => {
   console.log(BackgroundService.isRunning()); //false
    BackgroundService.start(veryIntensiveTask, options);
    return () => {
      BackgroundService.stop().then(()=> console.log("task is terminated"));
    };
  }, []);

[Rapsssito]

@alexfov, I am sorry, I am not familiar with redux-saga. I guess that React hook is only called once and the veryIntensiveTask does not dispatch several queries. I am sure no background task is running after restarting the app because I have tried to implement it (#43).

The only thing I can think of is some kind of cache/batch/concatenation of queries. Sorry, but I can't help you anymore with this.

[alexfov]

@Rapsssito could you explain why the app starts from previous state, when using this lib?

[alexfov]

Ok it's because BackgroundService doesn't stopped actually. If you stop it when an app is still opened there is no the issue. It seems like we can't know and use a callback when a user closes an app

[Rapsssito]

@alexfov, I am sorry, but background tasks are heavily managed by the OS. Each Android flavor has its own battery management rules and can cause incoherence between devices. If the user closes the app manually from the "open apps" is highly possible that the background task will also be killed.

I don't know why the app is starting from a previous state, for more info you may take a look at the docs for Headless JS in React Native. Also, make sure your AndroidManifest.xml is set to android:launchMode="singleTask": https://github.com/Rapsssito/react-native-background-actions/blob/cfbb451813f61ba9ddab71f9486b755bb6f2ed9d/examples/backgroundExample/android/app/src/main/AndroidManifest.xml#L20