I have used the collector app for over a year now. One of the things that I have noticed is that if I don't have cell phone or wifi access, I can't access my "on device" maps. I just get the spiral of death and no maps show up. this summer I will be traveling with my HS students to South Africa to collect data on wildlife movements in the Sabi Sands area, near Kruger National Park and we may at times not have access to either while we are out in the field. We are lucky this year that our camp has wifi access so in the morning we can access our maps before we go out into the field. However next year, we may not have the luxury from the start. We will always have access provided we go to the lodge but that can be more than 2 km away. Great for eventual syncing but not great way to have to go 2km to find our maps. I am wondering if anybody else has had this problem. I would love to know if I am missing something. Please let me know. If you don't know what I am talking about, please try this by finding a poor cell phone reception spot and try to access your "on device" map and see if you experience the same thing. I want to work this out before we leave this year on June 30th.
I had the same problem earlier and after a call to tech support with this as one of three problems I was having with Collector, we came up with a solution. After you have the map on the device open, before you go off network connectivity, you have to turn off wireless on the device. When I did this, I was fine. I haven't tried then opening a second map, but as long as you need only one map, this should work.
PS. I've had this problem with the Nexus tablets, but not with the iPad minis. They seem to be fine with the map whether or not wireless is turned on.
Thank Ina: Actually I get your solution and being doing that for some time. However, my problem is opening up a "on device" map when I don't have wifi nor cell phone reception. That is when i get the spiral of death--no map appears until either connection is made. Like I said this will make it a problem connecting to our maps (those that are on the phone) if we are out in the field with no service. It won't be a problem this year since we will have wifi and cell service at our camp. Next year we probably won't be so fortunate since we will be staying at a different location. Right now I am trying to access the "on device" maps in airplane mode to simulate this situation and so far no maps appear. So, I guess I am wondering why I need service in order to access the "on device" maps--aren't they on the phone or device? And if so, why do I need service to access them?
On the iPad I'm able to open maps in Collector even when I'm off network and am able to switch back and forth between maps that are on the device without any connection. I don't have access to any of the Nexus tablets at the moment, so can't test it on that. As Miaogeng Zhang asked, are you having trouble with both Android and iOS or are all your devices Android?
Does it happen in Android or iOS? Did you sign in before you go to the area without network? When no maps appear from on device, have you tried to force kill the Collector app?