Passing navigation params in react-navigation to component's methods

Trying to figure out how params are passed in react-navigation. Once a user selected an option from the Filter using the left header button, loadItems(filter) should be called with that filter as a parameter. How do I catch such event?

export default class FavoritesView extends Component {
    static navigationOptions = ({navigation}) => ({
        headerLeft: (
            <Button
                onPress={()=>{FavoritesView.showFilteringMenu(navigation)}}
                title="Filter"
            />
        ),
    });
    static showFilteringMenu(navigation) {
        let FILTERS = [
            'A',
            'B',
            'C'
        ];
        ActionSheet.showActionSheetWithOptions({
                title: "Filter options",
                options: FILTERS
            },
            (buttonIndex) => {
                navigation.setParams({
                    selectedOption: FILTERS[buttonIndex]
                }); // A parameter is set here
            });
    }
    loadItems(filter) { // This function should be called
        StorageService.getItems(filter).then(v => this.setState({ data: v }));
    }
    render() {
        let {navigation} = this.props;
        return (
            <SafeAreaView style={styles.container}>
                <NavigationEvents
                    onWillFocus={payload => this.loadItems()} // This works only for initial load
                />
            </SafeAreaView>
        );
    }
}