Updating watchface after notifications

I have a watchface that displays some data that takes a long time to draw, but doesn't change very often (~every 10 min) I have used a flag to tell onUpdate to only draw that part of the screen when the data has changed. When a notification like the move bar appears it overwrites that part of the screen and I need to set the flag to update the whole screen when that happens. How can I tell if a notification has occurred? It also happens after navigating back to the face after using some widgets, I tried setting the flag in onShow, but that isn't working.

Top Replies

All Replies

0 FlowState over 2 years ago

You have to redraw the whole screen in onUpdate(), because of the problem you just ran into: your watchface app has no way of knowing that the system overwrote all or part of the screen.

There's a lot of discussion about this in the forum.

e.g. https://forums.garmin.com/developer/connect-iq/f/discussion/256099/re-render-specific-parts-of-the-display-in-the-onupdate-method

jim_m_58 said:
You always want to redraw the whole screen in onUpdate. onPartialUpdate is the only place where you can just do a part.

On some devices the screen gets cleared before onUpdate is called, on others, a toast can cover part of the screen, and these things vary by device, and you don't see either in the sim.

Sounds like you are testing with a device that clears the screen, and you won't see that in the sim.

0 Raine H over 2 years ago in reply to FlowState

Thanks for that, looks like I'll have to put some effort into making that part of the display more efficient.

+1 jim_m_58 over 2 years ago in reply to Raine H

One thing to look at is separating the calculations for the data from the display of that data. Calculate every 10 minutes, and then display the results each time onUpdate is called. Mayby something like calculate the data, put the results in a buffered bitmap, and then just display that buffered bitmap each time onUpdate is called.

0 Raine H over 2 years ago in reply to jim_m_58

Thanks Jim, this is exactly what I'm going to try first.