I have a permanently running service app on the handset, one of the things it does is detect when there is an incoming phone call and send a message and some data to a companion app on a wearable device.
I'm wondering whether the app should establish the API to communicate with the wearable when it launches, or only when there is an incoming call and then disconnect afterwards.
Has anybody with wear development experience got any pros or cons of these approaches?
The service automatically starts at device start-up, and I've noticed if an attempt is made to create the GoogleApiClient/Wearable.API and get the wearable device node soon after rebooting there's a high chance of failure, therefore a disadvantage of establishing the wearable connection at app launch is its probably fail and will need to re-try or wait etc.
In general, to save on battery life, you want to minimize usage of any network connection on a mobile device. The general rule of thumb is: establish a connection only when needed, if you expect to use it again "soon" (e.g. within a minute or so), then keep it around, and close the connection when you are not going to use it for a longer while.
So in your case, since you are responding to phone calls (which should not happen every couple of minutes!), you should re-establish the connection every time. I am not sure though about the delay incurred in this case.