Don't crash if there's no bluetooth functionality (such as in an emulator)

Bug: 6079494
Change-Id: I12f729134407eaa719dc6a25e89a3b48476985e2

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

@@ -138,21 +138,26 @@ public final class BluetoothSettings extends DeviceListPreferenceFragment {
     public void onResume() {
         // resume BluetoothEnabler before calling super.onResume() so we don't get
         // any onDeviceAdded() callbacks before setting up view in updateContent()
+        if (mBluetoothEnabler != null) {
             mBluetoothEnabler.resume();
+        }
         super.onResume();
 
         if (mDiscoverableEnabler != null) {
             mDiscoverableEnabler.resume();
         }
         getActivity().registerReceiver(mReceiver, mIntentFilter);
-
+        if (mLocalAdapter != null) {
             updateContent(mLocalAdapter.getBluetoothState(), mActivityStarted);
         }
+    }
 
     @Override
     public void onPause() {
         super.onPause();
+        if (mBluetoothEnabler != null) {
             mBluetoothEnabler.pause();
+        }
         getActivity().unregisterReceiver(mReceiver);
         if (mDiscoverableEnabler != null) {
             mDiscoverableEnabler.pause();
@@ -161,6 +166,7 @@ public final class BluetoothSettings extends DeviceListPreferenceFragment {
 
     @Override
     public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
+        if (mLocalAdapter == null) return;
         boolean bluetoothIsEnabled = mLocalAdapter.getBluetoothState() == BluetoothAdapter.STATE_ON;
         boolean isDiscovering = mLocalAdapter.isDiscovering();
         int textId = isDiscovering ? R.string.bluetooth_searching_for_devices :

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

@@ -96,6 +96,7 @@ public abstract class DeviceListPreferenceFragment extends
     @Override
     public void onResume() {
         super.onResume();
+        if (mLocalManager == null) return;
 
         mLocalManager.setForegroundActivity(getActivity());
         mLocalManager.getEventManager().registerCallback(this);
@@ -106,6 +107,8 @@ public abstract class DeviceListPreferenceFragment extends
     @Override
     public void onPause() {
         super.onPause();
+        if (mLocalManager == null) return;
+
         removeAllDevices();
         mLocalManager.setForegroundActivity(null);
         mLocalManager.getEventManager().unregisterCallback(this);