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30-Jul-2011 |
David Brown <dab@google.com> |
Fix "emergency call from airplane mode" sequence
If you dial an emergency number while the device is in airplane mode, the
device needs to first take you *out* of airplane mode, and then (once the
radio is powered up) actually make the call.
In gingerbread we did this using an invisible activity called
EmergencyCallHandler, but that's a bad design for a few reasons:
- Visible display glitches during the activity transitions
- Potential bugs if you interfere with the activity lifecycle (e.g. by
pausing the EmergencyCallHandler by pressing Power at just the right
point.)
- The code is overly complicated.
Instead, it's cleaner to implement this sequence without using activities
at all. Here's the new design:
- The whole sequence is run by a helper class called EmergencyCallHelper
- If you try to dial 911 while in airplane mode, the CallController
notices this, lazily creates an EmergencyCallHelper instance, and
starts the sequence
- Then, the EmergencyCallHelper runs the next steps:
- power on the radio
- listen for the service state change when the radio comes up
- then launch the emergency call
- Retry if the call fails with an OUT_OF_SERVICE error
- Retry if we've gone 5 seconds without any response from the radio
- Finally, clean up when the emergency call disconnects successfully
There's also a corresponding update to the in-call UI: the InCallScreen
now knows how to put up a progress dialog (i.e. a "spinner") while we're
waiting for the radio to come on. That's controlled by a new
"progressIndication" field of the InCallUiState.
TESTED (with hacked telephony layer that doesn't actually dial 911):
- Call 911 in normal mode
- Call 911 in airplane mode
- After 911-from-airplane-mode sequence, double-check no wake locks still held
- Confirm no cosmetic glitches
Also tested some corner cases:
- Tested retry logic by using a temporary hack to deliberately ignore
the "service state changed" event
- Tested the "too many retries" case (using a temporary hack to make
all calls fail); confirmed that we give up after 6 tries and display
an error message
- Do the whole "911 from airplane mode" sequence twice in a row (to make
sure it works even if the EmergencyCallHelper object has already been
instantiated)
- Manually turn screen off in the middle of the sequence, confirm that
doesn't disrupt the call
Bug: 4195290
Bug: 4194458
Change-Id: I209768ffdc6b3d2bd4efd04474eed630284ec551
/packages/apps/Phone/src/com/android/phone/EmergencyCallHelper.java
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