Update the title by setParams

setParams.js

class UserPage extends React.Component {

  static navigationOptions: {
    header: ({state}) => ({
      left: (<NavBarBackButton />),
      title: (
        <UserPageTitle 
          userName={state.params.userName}
          profilePicUrl={state.params.profilePicUrl}
        />
      ),
      right: (<UserPageRight />),
    }),
  };

  updateNavBarTitle() {
    this.props.navigation.setParams({
      userName: 'Yin',
      profilePicUrl: 'http://www.example.com/myProfilePic.png',
    });
  }
  ...
}