Investigate UI freeze on main activity start

[trev]

Background

See #7.

What to change

Investigate UI freeze on main activity start

[fhd]

Adding Wladimir, I think he created this originally. Do you remember how this can be reproduced?

[trev]

Yes, I reported this originally - this was something nobody else could reproduce. The UI would freeze when I enabled Adblock Plus in its settings. Not sure whether this is still an issue (the report is very old), will check.

[rjeschke]

This issue still exists. I can reproduce this on my Galaxy S2.

It is caused by the full engine startup on opening the preferences app. There are now two ways to fix this:

1. Perform the engine startup in a background thread, display a beach-ball and update/unlock the UI when startup is done
2. As the proxy already runs as a service, we could of course just use the already running engine there. This would introduce some IPC/broadcasting to retrieve the needed infos but would speed up the preferences app's startup.

The second solution would definitely need more code refactoring and would need to be combined with solution 1 when there's no service running.

I'm still undecided on this issue's fix and would appreciate any input on this.

Also: shouldn't this be more like P2? Seems to me as a major pita.

[trev]

You are saying that two instances of the engine are currently running when we open preferences? Then - yes, we definitely need to fix that. I assumed that the UI already worked by querying the service.

[rjeschke]

Currently 'won't fix', explanation follows:

ABP for Android uses a service for filtering through the proxy. This service is a 'bound' service which is directly attached to the application (the preferences).

It seems like this service sometimes just dies without any notification which causes the long start-up delay.

A possible solution would be to use a 'real' service (i.e. a foreground service running in its own process). But this is now minor fix as this would create a real separation between the preferences and the proxy which then requires IPC to communicate.

So, currently this issue is 'backlogged'.