如何在 React Native 中删除事件侦听器或发射器侦听器

Question

I am trying to remove an event listener. The old way is deprecated. We are told to use.remove(). I am not sure how to refactor my code to do so. I am using a class component.

Can you provide an example of how to remove event listener. Currently my event listener is inside of another function. I have it that way as I may need to create another event listener every time the button is press and I need to remove the listener after the function runs.

startProcess = (result) => {
  //  stuff for running process
  console.log("your function is running its process");

  //deprecated but easy way to remove the event listener below
  // eventEmitter.removeListener('PreparePaywallFinished', onPreparePaywallFinished);

  //new way to remove event listen use remove() method on the EventSubscription returned by addEventListener()
  this.subscribeStartProcess.remove;
};

handleBtnPress = () => {
  // the listener
  eventEmitter.addListener("onMidiStart", this.startProcess);

  // emitter
  NativeModules.midiBridgeStart(true, 2);
};

render(){
  return <Button title='press' onPress={()=> handleBtnPress() />
}

Answer 1

You can use

window.removeEventListener('onMidiStart', handleonMidiStart);

the second argument in the removeEventListener is a variable to identify which event listed is being removed. A detailed description is being given here enter link description here