From 5f98c55aeff9cac25c8db038f467497a0e82307d Mon Sep 17 00:00:00 2001
From: Aaron Kromer <aaron.kromer@gmail.com>
Date: Wed, 24 May 2017 14:09:32 -0400
Subject: [PATCH] Fix where scanner thread is quit.

This fixes what I believe was a simply copy-paste error regarding how
the scanner thread is quit. This uses the scanner thread handler,
instead of the main thread handler, to schedule the `quit` operation.
This way any queued scan jobs (such as a stop) complete before we quit
the thread. This is what the comment states, but wasn't what the code
implemented.

The `mHandler.removeCallbacksAndMessages` is removed from the background
job as `destroy` is already on the main thread. So we want to clear any
other jobs still in the queue to run later now as we are in the process
of destroying everything.
---
 .../beacon/service/scanner/CycledLeScanner.java       | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/main/java/org/altbeacon/beacon/service/scanner/CycledLeScanner.java b/src/main/java/org/altbeacon/beacon/service/scanner/CycledLeScanner.java
index a176da53d..fb8126ca8 100644
--- a/src/main/java/org/altbeacon/beacon/service/scanner/CycledLeScanner.java
+++ b/src/main/java/org/altbeacon/beacon/service/scanner/CycledLeScanner.java
@@ -16,6 +16,7 @@
 import android.os.SystemClock;
 import android.support.annotation.MainThread;
 import android.support.annotation.NonNull;
+import android.support.annotation.WorkerThread;
 
 import org.altbeacon.beacon.BeaconManager;
 import org.altbeacon.beacon.logging.LogManager;
@@ -198,17 +199,19 @@ public void setDistinctPacketsDetectedPerScan(boolean detected) {
     @MainThread
     public void destroy() {
         LogManager.d(TAG, "Destroying");
+
+        // Remove any postDelayed Runnables queued for the next scan cycle
+        mHandler.removeCallbacksAndMessages(null);
+
         // We cannot quit the thread used by the handler until queued Runnables have been processed,
         // because the handler is what stops scanning, and we do not want scanning left on.
         // So we stop the thread using the handler, so we make sure it happens after all other
         // waiting Runnables are finished.
-        mHandler.post(new Runnable() {
-            @MainThread
+        mScanHandler.post(new Runnable() {
+            @WorkerThread
             @Override
             public void run() {
                 LogManager.d(TAG, "Quitting scan thread");
-                // Remove any postDelayed Runnables queued for the next scan cycle
-                mHandler.removeCallbacksAndMessages(null);
                 mScanThread.quit();
             }
         });