Aw: doing MVP outside activities/places - good idea? (or how to change place token without going to same place with changed token)
Take a look
at: https://groups.google.com/d/topic/google-web-toolkit/OsDpLtBoTQo/discussion
I had nearly the same problem. Short version: If you have non singleton
activities they will be restarted for every PlaceChangeEvent. If you want to
avoid this you need to cache your Activity. But once you cache your activity
if lives longer than its place it is started for. Thus the activity has to
be notified once a PlaceChangeEvent occurs for the same place but with
different internal state. This can be done by a method defined in every
activity through a custom activity interface that extends Activity (e.g.
setPlace() called by your activity caching code) or by letting the activity
itself listen for PlaceChangeEvent and let the activity decide if it needs
to update or not. That way you can always use placeController.goTo(new
Place(new state)) to update the URL according to the current app state.
First I have used myActivity.setPlace() to notify the activity as I need
this method anyways because of GIN. But that way you need an extra flag in
your activity so you can decide if the activity is already running and you
have to update it or if its not yet started and you can do the work once its
started. So basically
public void setPlace(...) {
//storing place information in activity variables
//
//update activity/view
if(isRunning) {
doUpdate();
}
}
public void start(...) {
running = true;
doUpdate();
}
So I prefer it to let the activity listen for PlaceChangeEvents. That way
you won't need the extra boolean flag.
-- J.
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Re: Aw: doing MVP outside activities/places - good idea? (or how to change place token without going to same place with changed token)
thx! absolutly the same ideas came to my mind and let me post this question. (i have to admit that not only thomas' but also your answers and suggestion directed me to this approach) i read the discussion you mentioned above and one question remains: is it a good idea to do things this way? my feeling is that the way mauro did it in layoutMVP-Example is the way the GWT MVP Framework implies?! or the other way around: what consequences to bear (beside the update state problem) if i go this way any further? (i am in the privileged position to could still do any refactoring) for example what about activity methods called on place change like mayStop(), onCancel()... - mayStop should only be called if place changes (not only state)?! I also have a bad feeling about singleton activities (each one referencing some presenters). somehow i like the idea of disposable activities and presenters. (having two people (you and thomas) doing it this way calms me down ;-) ) the advantage of activity=presenter/many activitymapper approach (imho please correct if i am wrong) is that you could choose caching per display area. so activities that shouldn't be restarted on place change will be cached via cached mappers, activities that should be updated on every place changed will be mapped via normal mappers and return new instances every time. So imho there is a solution for our problem by doing it the other way ?! -- You received this message because you are subscribed to the Google Groups Google Web Toolkit group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/TZem1DCrJiAJ. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
