Refreshing Bluetooth devices will clear all available devices.

Bug: 16851309
Change-Id: I9ffb1ddaeb8e785be145ea79467fc361a022d8d7

src/com/android/settings/bluetooth/BluetoothSettings.java

@@ -249,6 +249,8 @@ public final class BluetoothSettings extends DeviceListPreferenceFragment implem
         if (!mAvailableDevicesCategoryIsPresent) {
             getPreferenceScreen().addPreference(mAvailableDevicesCategory);
         }
+        mLocalManager.getCachedDeviceManager().clearCachedDevices();
+        mAvailableDevicesCategory.removeAll();
         mLocalAdapter.startScanning(true);
     }
 

src/com/android/settings/bluetooth/CachedBluetoothDeviceManager.java

@@ -86,7 +86,9 @@ final class CachedBluetoothDeviceManager {
             BluetoothDevice device) {
         CachedBluetoothDevice newDevice = new CachedBluetoothDevice(mContext, adapter,
             profileManager, device);
+        synchronized (mCachedDevices) {
             mCachedDevices.add(newDevice);
+        }
         return newDevice;
     }
 
@@ -110,6 +112,10 @@ final class CachedBluetoothDeviceManager {
         return device.getAddress();
     }
 
+    public synchronized void clearCachedDevices() {
+        mCachedDevices.clear();
+    }
+
     public synchronized void onScanningStateChanged(boolean started) {
         if (!started) return;
 

src/com/android/settings/bluetooth/DeviceListPreferenceFragment.java

@@ -167,6 +167,12 @@ public abstract class DeviceListPreferenceFragment extends
      }
 
     void createDevicePreference(CachedBluetoothDevice cachedDevice) {
+        if (mDeviceListGroup == null) {
+            Log.w(TAG, "Trying to create a device preference before the list group/category "
+                    + "exists!");
+            return;
+        }
+
         BluetoothDevicePreference preference = new BluetoothDevicePreference(
                 getActivity(), cachedDevice);