Ratio of GWT Places to Activities to Screen?

Question

I'm trying to write a GWT app that reuses the same template for every "page" (place). There are 4 main "pages" of the app:

Dashboard page (http://www.mywebapp.com/#dashboard)
Calculator page (http://www.mywebapp.com/#calc)
Configurator page (http://www.mywebapp.com/#config)
Login page (http://www.mywebapp.com/#login)

Each "page" has the same templated look-and-feel: (1) a header section that contains the logo and the navigation menu, (2) a content section that contains "page"-specific content (i.e. will be different for the #dashboard place, #login place, etc.), and (3) a footer section that contains some links. So you see, the only thing that changes from page-to-page is the content section. Just like an ordinary, templated web site.

The thing is, each "page" (place) is actually a fairly complicated UI with many different panels consisting of lots of widgets. As the user interacts with the app, these panels will come into and out of existence and the display will be changing all the time. For instance, on the #calc page, the user can select which "mode" to display a calculator in: either as Basic or as Advanced. When the user selects Advanced, several additional panels will display (in addition to the Basic panel).

It would be nice to be able to keep such actions in history, so that the user can bookmark the app in either Basic or Advanced mode, so something like:

http://www.mywebapp.com/#calc/basic; or
http://www.mywebapp.com/#calc/advanced

Here's the problem:

We already have several "levels" of activities/places going on here. At the "app"-level, we have the template that needs to be displayed to the user when the MyWebAppModule implements EntryPoint downloads. This TemplatePlace is the default/initial place that is registered with the HistoryHandler before calling:

public class MyWebAppModule implements EntryPoint {
    @Override
    public void onModuleLoad() {
        // ...

        // The first place we go to when this module downloads.
        TemplatePlace templatePlace = getSomehow();

        historyHandler.register(placeController, eventBus, templatePlace);
        historyHandler.handleCurrentHistory();
    }
}

Next, we have all the different "pages": DashboardPlace, CalculatorPlace, etc. that all have their own unique views/displays. For instance when the user clicks the Calculator link to go to CalculatorPlace, it should render a different view than when the identify that they want to use the calculator in Basic or Advanced mode.

Finally, we have the different display regions, panels, etc. inside each page/place, such as the BasicCalculatorPlace and AdvancedCalculatorPlace. This is what I mean by different "levels" of navigation:

Application-level (a template to apply to all pages/places)
Page- or place-level
Display- or panel-level

The question:

I want to achieve bookmarkable URLs (places) for when the user does all of the following:

Goes to the home page (http://www.mywebapp.com)
Goes to any of the "pages" (http://www.mywebapp.com/#calc, etc.)
Uses the pages/places which cause page-specific panel or display configurations (http://www.mywebapp.com\#calc\#advanced, etc.)

How many Activities and Places do I create? How many ActivityManagers? I guess I'm asking for how granular Activities/Places need to be for each "level" of bookmarkable UI. Thanks in advance!

Andrei Volgin Andrei Volgin · Accepted Answer · 2012-11-10T19:08:53

I think you only need one ActivityManager and one Activity per "page". You can make your "header" and "footer" into widgets that can be reused in each page.

You can bookmark different states of the same page by using tokens. For example, you can set a token to "basic" - it would tell the CalculatorActivity to show basic calculator panel. The URL will look like:

www.myApp.com/?#Calculator:basic

When a user clicks on a widget to select an advanced option, you do

PlaceController.goTo(new CalculatorPlace("advanced"));

The CalculatorActivity will get the CalculatorView (which is already displayed), it will see that the token is set to "advanced" and it will instruct this view to show advanced panels.

Note that you can make your tokens as detailed as necessary and then parse them in Activity. For example, you can have something like

www.myApp.com/?#Calculator:option=basic&position=top&theme=pink

Ratio of GWT Places to Activities to Screen?

The question:

1 Answers