Merge pull request #674 from AltBeacon/warn-of-scan-job-disabling-con…

…sequences

add warning about disabling scan jobs on Android 8+

CHANGELOG.md

@@ -1,11 +1,13 @@
 ### 2.14 / 2018-05-17
 
 Enhancements:
+
+ - Add warnings about disabling scheduled scan jobs on Android 8+ (#674, David G. Young)
  - Add warning about setting short scan periods on Android 8 (#677, David G. Young)
  - BeaconTransmitter advertisements may be configured as connectable (#683, Michael Harper)
 
 Bug Fixes:
- - Fix crashes of BluetoothMedic caused by Bluetooth being turned off (#675, David g. Young) 
+ - Fix crashes of BluetoothMedic caused by Bluetooth being turned off (#675, David G. Young) 
 
 ### 2.13.1 / 2018-03-05
 

src/main/java/org/altbeacon/beacon/BeaconManager.java

@@ -553,6 +553,10 @@ public void setBackgroundMode(boolean backgroundMode) {
      * otherwise beacon scans may be run only once every 15 minutes in the background, and no low
      * power scans may be performed between scanning cycles.
      *
+     * Setting this value to false will disable ScanJobs when the app is run on Android 8+, which
+     * can prohibit delivery of callbacks when the app is in the background unless the scanning
+     * process is running in a foreground service.
+     *
      * This method may only be called if bind() has not yet been called, otherwise an
      * `IllegalStateException` is thown.
      *
@@ -569,8 +573,13 @@ public void setEnableScheduledScanJobs(boolean enabled) {
                     " availble prior to Android 5.0");
             return;
         }
+        if (enabled && android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            LogManager.w(TAG, "Disabling ScanJobs on Android 8+ may disable delivery of "+
+                    "beacon callbacks in the background unless a foreground service is active.");
+        }
         mScheduledScanJobsEnabled = enabled;
     }
+
     public boolean getScheduledScanJobsEnabled() {
         return mScheduledScanJobsEnabled;
     }