The entire UI flickers every time there is an API sync

[heartsucker]

It seems as if the whole app disappears and is repainted after the sync. I use xfcd/xmonad on my desktop, and the "flicker" affects other tiles which leads me to believe that the whole display actually disappears and reappears, and not just that the app has a strange flash itself during this repainting.

(on master at commit 1e96664)

[heartsucker]

This is a hard blocker for #16. Attempting to compose a message will result in the message content being deleted during a "flicker".

[heartsucker]

Trying to work on this now by using the QAbstractModel pattern for all the data the GUI needs to render.

[redshiftzero]

Taking a step back, the entire pane is flashing for two reasons:

1. the ConversationView is the parent of several other objects which should be more cleanly separated (currently the ConversationView represents almost the entire right hand side of the client) and,
2. because we always redraw when either an API sync completes or every few seconds, even if nothing changed

To resolve issue 1, the right side of the client should be a container object that contains:

• ConversationView
• SourceProfileShortWidget which itself contains widgets
• the reply field

(Currently SourceProfileShortWidget and the reply box are children of ConversationView)

API syncs or updates as messages/replies are decrypted should only modify the ConversationView part of the UI. Just adding this container object and resolving issue 1 should be sufficient to unblock the reply feature (let me know if you disagree) and would need to be done even when we move to using QAbstractModel.

To resolve issue 2 I agree we should move to QAbstractModel. ConversationView would be a QAbstractModel which will resolve the flashing and will only render updates when a change is made (btw I did a bit of experimenting here today using QAbstractListModel which may be a useful reference). Using this MVC pattern should reduce code complexity as the UI will just reflect the models so we no longer need to explicitly redraw the UI when something changes - that should be done by qt's signals and slots which we get for free when we use the qt models properly.