Persistence of the Dc content between calls to onUpdate()

In the context of a watch face app, when its view gets an onUpdate() call, can it assume that previously drawn Dc content is still there?

Or is it possible that the OS could wipe the Dc clean now and then?

This is not documented. In the simulator the assumption seems to hold. On the actual watch *it seems* it does not.

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eau_de_vie 2 months ago in reply to jim_m_58 +1

Lol, ok.

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0 jim_m_58 2 months ago in reply to FlowState

As you've never even done a watch face, you should start with doing one so you'll understand the basics.

0 FlowState 2 months ago in reply to jim_m_58

jim_m_58 said:
As you've never even done a watch face, you should start with doing one so you'll understand the basics.

You don't have to convince me, convince the people like OP who are asking for this. You're the one posting in this thread saying it's an invalid feature request.

I'm just curious about whether it's at all possible in theory to meaningfully save battery life if onUpdate() allowed partial updates (for watchfaces and for any other type of app.)

I think one strong argument against needing this feature request (for watchfaces) is that onUpdate() is only called frequently during high power mode (for a few seconds after the user turns their wrist). The rest of the time it would be called once per minute. So you'd really only be optimizing for a fairly rare case (how often does a user turn their wrist to look at their watch outside of an activity?)

But I was just curious. I actually don't care all that much tbh.