How do i make a TabNavigator button push a modal screen with React Navigation

Question

Using the React Navigation tab navigator https://reactnavigation.org/docs/navigators/tab how do I make one of the tab buttons push the screen up as a full screen modal? I see the stack navigator has a mode=modal option. how do I get that mode to be used when clicking on the TakePhoto tab button? Clicking on it currently still shows the tab bar on the bottom.

const MyApp = TabNavigator({
  Home: {
    screen: MyHomeScreen,
  },
  TakePhoto: {
    screen: PhotoPickerScreen, // how can I have this screen show up as a full screen modal?
  },
});

Answer 1

Actually, there is no support in react-navigation to change the way of presentation on the fly from default to modal (see the discussion about this here). I ran into the same issue and solved it by using a very top StackNavigator with headerMode set to none and mode set to modal:

const MainTabNavigator = TabNavigator(
    {
        Tab1Home: { screen: Tab1Screen },
        Tab2Home: { screen: Tab2Screen }
    }
);

const LoginRegisterStackNavigator = StackNavigator({
    Login: { screen: LoginScreen }
});

const ModalStackNavigator = StackNavigator({
    MainTabNavigator:          { screen: MainTabNavigator            },
    LoginScreenStackNavigator: { screen: LoginRegisterStackNavigator }
}, {
    headerMode: 'none',
    mode:       'modal'
});

This allows me to do the following (using redux) in Tab1Screen and Tab2Screen to bring up the modal view from wherever I want:

this.props.navigation.navigate('LoginScreenStackNavigator');