React Native Background Timer
Emit event periodically (even when app is in the background).
Installation
-
If you use Expo to create a project you'll just need to "eject".
expo eject -
Install React Native Background Timer package.
yarn add react-native-background-timer# or using npmnpm install react-native-background-timer --save -
Link React Native Background Timer library. This step is not necessary when you use React Native >= 0.60 (and your app is not ejected from Expo).
react-native link react-native-background-timer -
If you use CocoaPods or React Native >= 0.60 (and your app is not ejected from Expo) or your app is ejected from Expo, then before running your app on iOS, make sure you have CocoaPods installed and run:
cd iospod install
Link the library manually if you get errors:
- Android:
TypeError: Cannot read property 'setTimeout' of undefined
orTypeError: null is not an object (evaluating 'RNBackgroundTimer.setTimeout')
- iOS:
Native module cannot be null
Android manual linking
-
android/settings.gradle
+ include ':react-native-background-timer'+ project(':react-native-background-timer').projectDir = new File(rootProject.projectDir, '../node_modules/react-native-background-timer/android') -
android/app/build.gradle
dependencies {+ implementation project(':react-native-background-timer')} -
android/app/src/main/java/com/your-app/MainApplication.java
+ import com.ocetnik.timer.BackgroundTimerPackage;@Overrideprotected List<ReactPackage> getPackages() {return Arrays.<ReactPackage>asList(+ new BackgroundTimerPackage());}
iOS manual linking
-
ios/Podfile
+ pod 'react-native-background-timer', :path => '../node_modules/react-native-background-timer'
Usage
;
Crossplatform
To use the same code both on Android and iOS use runBackgroundTimer() and stopBackgroundTimer(). There can be used only one background timer to keep code consistent.
BackgroundTimer;//rest of code will be performing for iOS on background too BackgroundTimer; //after this call all code on background stop run.
iOS
After iOS update logic of background task little bit changed. So we can't use as it was. You have to use only start() and stop() without parameters. And all code that is performing will continue performing on background including all setTimeout() timers.
Example:
BackgroundTimerstart;// Do whatever you want incuding setTimeout;BackgroundTimer;
If you call stop() on background no new tasks will be started! Don't call .start() twice, as it stop performing previous background task and starts new. If it will be called on backgound no tasks will run.
Android
You can use the setInterval
and setTimeout
functions.
This API is identical to that of react-native
and can be used to quickly replace existing timers
with background timers.
// Start a timer that runs continuous after X millisecondsconst intervalId = BackgroundTimer; // Cancel the timer when you are done with itBackgroundTimer;
// Start a timer that runs once after X millisecondsconst timeoutId = BackgroundTimer; // Cancel the timeout if necessaryBackgroundTimer;
Obsolete
Obsolete usage which doesn't support multiple background timers.
; ;
const EventEmitter = Platform;
// start a global timerBackgroundTimerstart5000; // delay in milliseconds only for Android
// listen for eventEventEmitter;
// stop the timerBackgroundTimer;