android(fix): duplicate state handling, double AACP connect, heart rate parsing, island window threading

[QuerTeal]

Summary

This PR fixes six independent bugs in android/rewrite. I found them while testing on a Galaxy S26 Ultra (One UI 9.0 / Android 17, no root) with AirPods Pro 3 (A3063, firmware build 9442752). Each bug is its own commit.

1. Every device state change was handled twice

loadDevices() → createDevice() registers state, settings and metadata observers for each bonded device. onDeviceConnected() then replaced deviceJobs[mac] with a second set without cancelling the first. The orphaned jobs kept collecting.

As a result:

• Each heart rate sample was inserted into the local DB and Health Connect twice.
• MediaController.sendPlay() / sendPause() fired twice on each ear detection change.
• Every log line from the observers appeared twice.

Fix: cancel the existing jobs before registering the new ones.

2. A second AACP socket was opened while the first was still connecting

The guard in onDeviceConnected() only returns early for CONNECTED. When connect() was already running (tapping the device icon in DeviceListScreen, or ACL_CONNECTED followed by ACTION_UUID), a second L2CAP socket was opened. The init handshake then ran on both sockets.

Fix: AppleDevice.connect() now does an atomic getAndUpdate on the connection state. It returns early if the state is already CONNECTING or CONNECTED.

3. Heart rate readings >= 128 bpm were discarded

payload[1].toInt() sign-extends the byte, so 128–255 bpm became negative and failed the 1..300 check. That covers most readings during a workout.

Fix: read the byte as unsigned (and 0xFF). The raw payload is now logged next to each reading, which helps with decoding the remaining fields.

4. The island popup never appeared

processComponentStateChange() runs inside observeAppleState() on Dispatchers.IO. The call to showIsland() → WindowManager.addView() therefore threw Can't create handler inside thread ... that has not called Looper.prepare().

Fix: showIsland() re-dispatches itself to Dispatchers.Main when called off the main thread, and the island close() call does the same.

5. Island battery update crashed off the main thread (added in a follow-up commit)

Once fix 4 made the island actually appear, a second path was exposed. observeAppleState() (on Dispatchers.IO) called islandWindow.updateBattery() whenever the battery changed while the island was visible, and that crashed with CalledFromWrongThreadException.

This typically happened right after putting the AirPods in, which also killed the audio reconnect that was in progress. The update is now dispatched to the main thread.

Tested: before the fix, the app crashed when the battery changed while the island was visible. After the fix, a battery update arrived 2 s after the island was shown and there was no crash.

6. Unreliable heart rate samples during sensor warm-up (added in a follow-up commit)

The first samples after the sensor starts are unreliable. In testing: 169 bpm, then 91, 74, 77, while resting at about 75.

Payload bytes observed across samples:

Byte(s)	Warm-up samples	After warm-up
payload[17]	bit 0 set (81)	bit 0 clear
payload[16..17]	82 81 on the first sample, then 02 81	00 00; briefly 00 80 during motion
payload[2] (looks like confidence)	20	120–237
payload[3]	sample sequence number	sample sequence number

Samples with bit 0 of payload[17] set are now skipped, so they are not shown, stored, or written to Health Connect. hrmState stays WAITING until the sensor settles.

Tested:

• Replayed against a recorded session of 112 samples: the 4 warm-up samples were dropped and the 108 others (75–147 bpm, including the 00 80 ones) were kept.
• On device, across two more sessions: exactly the first 4 samples were skipped each time (169, 100, 76, 76 and 169, 117, 67, 71), followed by normal readings (70–82 bpm).

Testing

Tested on a Galaxy S26 Ultra (SM-S948N, One UI 9.0, SDK 37, rootless native L2CAP) with AirPods Pro 3 (A3063, fw 9442752), using assembleFossDebug.

	Before	After
Observer callbacks per state change	2	1
sendPlay per ear-in	2	1
connecting... per connection (after tapping the device icon)	2, with 4 handshakes	1
Heart rate while exercising	first sample logged Invalid heart rate value: -87; everything ≥ 128 dropped	128 → 147 bpm recorded
Island on ear-in	RuntimeException in log, nothing shown	shown; removed when both buds are taken out

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