Merge pull request #558 from AltBeacon/fix-bugs-with-nonzero-foregrou…

…nd-between-scan-period Fix bugs with nonzero foreground betweenScanPeriod
AltBeacon · Aug 16, 2017 · b34a2ff · b34a2ff
2 parents 04bb521 + 4bf2d9f
commit b34a2ff
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,15 @@
+### Development
+
+Enhancements:
+
+Bug Fixes:
+
+ - Fix "Scanning too frequently" error with non-zero betweenScanPeriod
+   and scanPeriod+betweenScanPeriod < 6000, and full-power scanning
+   staying on for foreground scans with a non-zero betweenScanPeriod
+   (#555, David G. Young)
+
+
 ### 2.12 / 2017-08-07
 
 Enhancements:

diff --git a/src/main/java/org/altbeacon/beacon/service/scanner/CycledLeScannerForLollipop.java b/src/main/java/org/altbeacon/beacon/service/scanner/CycledLeScannerForLollipop.java
@@ -91,11 +91,20 @@ protected boolean deferScanIfNeeded() {
                 if (secsSinceLastDetection > BACKGROUND_L_SCAN_DETECTION_PERIOD_MILLIS) {
                     mBackgroundLScanStartTime = SystemClock.elapsedRealtime();
                     mBackgroundLScanFirstDetectionTime = 0l;
-                    LogManager.d(TAG, "This is Android L. Doing a filtered scan for the background.");
-
+                    LogManager.d(TAG, "This is Android L. Preparing to do a filtered scan for the background.");
                     // On Android L, between scan cycles do a scan with a filter looking for any beacon
                     // if we see one of those beacons, we need to deliver the results
-                    startScan();
+                    // Only scan between cycles if the between can cycle time > 6 seconds.  A shorter low
+                    // power scan is unlikely to be useful, and might trigger a "scanning too frequently"
+                    // error on Android N.
+                    if (mBetweenScanPeriod > 6000l) {
+                        startScan();
+                    }
+                    else {
+                        LogManager.d(TAG, "Suppressing scan between cycles because the between scan cycle is too short.");
+                    }
+
+
                 } else {
                     // TODO: Consider starting a scan with delivery based on the filters *NOT* being seen
                     // This API is now available in Android M
@@ -157,19 +166,21 @@ protected void startScan() {
             return;
         }
         List<ScanFilter> filters = new ArrayList<ScanFilter>();
-        ScanSettings settings;
+        ScanSettings settings = null;
 
-        if (mBackgroundFlag && !mMainScanCycleActive) {
+        if (!mMainScanCycleActive) {
             LogManager.d(TAG, "starting filtered scan in SCAN_MODE_LOW_POWER");
             settings = (new ScanSettings.Builder().setScanMode(ScanSettings.SCAN_MODE_LOW_POWER)).build();
             filters = new ScanFilterUtils().createScanFiltersForBeaconParsers(
-                    mBeaconManager.getBeaconParsers());
+                          mBeaconManager.getBeaconParsers());
         } else {
             LogManager.d(TAG, "starting non-filtered scan in SCAN_MODE_LOW_LATENCY");
             settings = (new ScanSettings.Builder().setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)).build();
         }
 
-        postStartLeScan(filters, settings);
+        if (settings != null) {
+            postStartLeScan(filters, settings);
+        }
     }
 
     @Override