react native - Refresh previous screen on goBack()

Question

I am new to React Native. How can we refresh/reload previous screen when returning to it by calling goBack()?

Lets say we have 3 screens A, B, C:

A -> B -> C

When we run goBack() from screen C it goes back to screen B but with old state/data. How can we refresh it? The constructor doesn't get called 2nd time.

Answer 1

Adding an Api Call in a focus callBack in the screen you're returning to solves the issue.

componentDidMount() {
    this.props.fetchData();
    this.willFocusSubscription = this.props.navigation.addListener(
      'willFocus',
      () => {
        this.props.fetchData();
      }
    );
  }

  componentWillUnmount() {
    this.willFocusSubscription.remove();
  }

UPDATE 2021:

  componentDidMount() {
    this.props.fetchData();
    this.willFocusSubscription = this.props.navigation.addListener(
      'willFocus',
      () => {
        this.props.fetchData();
      }
    );
  }

  componentWillUnmount() {
    this.willFocusSubscription();
  }

If you use React Hook:

  React.useEffect(() => {
      fetchData();
      const willFocusSubscription = props.navigation.addListener('focus', () => {
        fetchData();
    });

    return willFocusSubscription;
}, []);