Fix for NPE when group selection fragment is no longer attached to activity.

src/org/thoughtcrime/securesms/ContactSelectionActivity.java

@@ -84,7 +84,7 @@ public class ContactSelectionActivity extends PassphraseRequiredSherlockFragment
   private void handleSelectionFinished() {
     recipients = contactsFragment.getSelectedContacts();
     recipients.append(recentFragment.getSelectedContacts());
-    recipients.append(groupsFragment.getSelectedContacts());
+    recipients.append(groupsFragment.getSelectedContacts(this));
 
     Intent resultIntent = getIntent();
     resultIntent.putExtra("recipients", this.recipients);

src/org/thoughtcrime/securesms/ContactSelectionGroupsFragment.java

@@ -84,12 +84,12 @@ public class ContactSelectionGroupsFragment extends SherlockListFragment
     this.getListView().setFocusable(true);
   }
 
-  public Recipients getSelectedContacts() {
+  public Recipients getSelectedContacts(Context context) {
     List<Recipient> recipientList = new LinkedList<Recipient>();
 
     for (GroupData groupData : selectedGroups.values()) {
       List<ContactData> contactDataList = ContactAccessor.getInstance()
-          .getGroupMembership(getActivity(), groupData.id);
+          .getGroupMembership(context, groupData.id);
 
       Log.w("GroupSelectionListActivity", "Got contacts in group: " + contactDataList.size());