How to launch function when screen in reached in TabNavigator ? [REACT NAVIGATION]

Question

The problem is that the functions constructor() and componentDidMount() are called when the tab navigator is loaded. And I need to call function each time the user reachs the screen named myScreeen for example How we can do that ?

Answer 1

I found hack :

    <Navigator
    onNavigationStateChange={(prevState, currentState) => {
  const getCurrentRouteName = (navigationState) => {
    if (!navigationState) return null;
    const route = navigationState.routes[navigationState.index];
    if (route.routes) return getCurrentRouteName(route);
    return route.routeName;
  };
  let currentRoute = getCurrentRouteName(currentState);
  if(currentRoute == "A") {
     console.log("TRIGGER")
}}/>;

And then you listen to the log in your component, like this :

  componentDidMount() {
    let slf = this;
    let log = console.log;
    console.log = function(txt) {
      if(txt == "TRIGGER") {
        slf.myFunction();  // CALL HERE YOUR FUNCTION
      } else {
        log.apply(console, arguments);
      }
    }
  }