Filter contacts on background

app/src/main/java/eu/faircode/email/AdapterContact.java

@@ -65,6 +65,7 @@ import java.io.InputStream;
 import java.text.NumberFormat;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.ExecutorService;
 
 public class AdapterContact extends RecyclerView.Adapter<AdapterContact.ViewHolder> {
     private Fragment parentFragment;
@@ -84,6 +85,9 @@ public class AdapterContact extends RecyclerView.Adapter<AdapterContact.ViewHold
 
     private NumberFormat NF = NumberFormat.getNumberInstance();
 
+    private static final ExecutorService executor =
+            Helper.getBackgroundExecutor(1, "contacts");
+
     public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener, View.OnLongClickListener {
         private View view;
         private ImageView ivType;
@@ -377,12 +381,15 @@ public class AdapterContact extends RecyclerView.Adapter<AdapterContact.ViewHold
 
         all = contacts;
 
+        new SimpleTask<List<TupleContactEx>>() {
+            @Override
+            protected List<TupleContactEx> onExecute(Context context, Bundle args) throws Throwable {
                 List<TupleContactEx> filtered;
                 if (types.size() == 0)
-            filtered = all;
+                    filtered = contacts;
                 else {
                     filtered = new ArrayList<>();
-            for (TupleContactEx contact : all)
+                    for (TupleContactEx contact : contacts)
                         if (types.contains(contact.type))
                             filtered.add(contact);
                 }
@@ -399,6 +406,11 @@ public class AdapterContact extends RecyclerView.Adapter<AdapterContact.ViewHold
                             items.add(contact);
                 }
 
+                return items;
+            }
+
+            @Override
+            protected void onExecuted(Bundle args, List<TupleContactEx> items) {
                 DiffUtil.DiffResult diff = DiffUtil.calculateDiff(new DiffCallback(selected, items), false);
 
                 selected = items;
@@ -424,7 +436,14 @@ public class AdapterContact extends RecyclerView.Adapter<AdapterContact.ViewHold
                         Log.d("Changed @" + position + " #" + count);
                     }
                 });
-        diff.dispatchUpdatesTo(this);
+                diff.dispatchUpdatesTo(AdapterContact.this);
+            }
+
+            @Override
+            protected void onException(Bundle args, Throwable ex) {
+                Log.unexpectedError(parentFragment.getParentFragmentManager(), ex);
+            }
+        }.setExecutor(executor).execute(context, owner, new Bundle(), "contacts:filter");
     }
 
     public void search(String query) {