Getting undefined is not an object evaluating _this.props.navigation

Question

I\'m using DrawerNavigator and I have 3 pages: Router page, mainScreen and a photos page,
I maked a header navbar are

Answer 1

class ProductScreen extends Component {

export default ProductScreen; // make sure bottom this line mention

Call this

  <TouchableOpacity
        onPress = {() => this.props.navigation.navigate('ProductAddScreen')}
        activeOpacity={0.7} style={styles.button}>

       <Text style={styles.message}>{this.state.notFound} </Text>

  </TouchableOpacity>