Load new list without calling startActivity

app/src/main/java/com/todoroo/astrid/activity/MainActivity.java

@@ -65,7 +65,6 @@ import org.tasks.fragments.CommentBarFragment;
 import org.tasks.gtasks.PlayServices;
 import org.tasks.injection.ActivityComponent;
 import org.tasks.injection.InjectingAppCompatActivity;
-import org.tasks.intents.TaskIntents;
 import org.tasks.preferences.DefaultFilterProvider;
 import org.tasks.preferences.Preferences;
 import org.tasks.receivers.RepeatConfirmationReceiver;
@@ -378,17 +377,18 @@ public class MainActivity extends InjectingAppCompatActivity
   }
 
   @Override
-  public void onFilterItemClicked(FilterListItem item) {
-    if (item == null) {
-      item = defaultFilterProvider.getDefaultFilter();
-    }
+  public void onFilterItemClicked(@Nullable FilterListItem item) {
     TaskEditFragment tef = getTaskEditFragment();
     if (tef != null) {
       getTaskEditFragment().save();
     }
 
-    if (item instanceof Filter) {
-      startActivity(TaskIntents.getTaskListIntent(this, (Filter) item));
+    if (item == null || item instanceof Filter) {
+      disposables.add(
+          Single.fromCallable(() -> newTaskListFragment((Filter) item))
+              .subscribeOn(Schedulers.io())
+              .observeOn(AndroidSchedulers.mainThread())
+              .subscribe(this::openTaskListFragment));
     }
   }
 

app/src/main/java/org/tasks/intents/TaskIntents.java

@@ -7,6 +7,7 @@ import androidx.core.app.TaskStackBuilder;
 import com.google.common.base.Strings;
 import com.todoroo.astrid.activity.MainActivity;
 import com.todoroo.astrid.api.Filter;
+import org.jetbrains.annotations.Nullable;
 
 public class TaskIntents {
 
@@ -27,7 +28,7 @@ public class TaskIntents {
     return taskListIntent;
   }
 
-  public static Intent getTaskListIntent(Context context, final Filter filter) {
+  public static Intent getTaskListIntent(Context context, @Nullable Filter filter) {
     Intent intent = new Intent(context, MainActivity.class);
     if (filter != null) {
       intent.putExtra(MainActivity.OPEN_FILTER, filter);

app/src/main/java/org/tasks/ui/NavigationDrawerFragment.java

@@ -30,6 +30,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import javax.inject.Inject;
+import org.jetbrains.annotations.Nullable;
 import org.tasks.LocalBroadcastManager;
 import org.tasks.R;
 import org.tasks.filters.FilterProvider;
@@ -262,7 +263,7 @@ public class NavigationDrawerFragment extends InjectingFragment {
   }
 
   public interface OnFilterItemClickedListener {
-    void onFilterItemClicked(FilterListItem item);
+    void onFilterItemClicked(@Nullable FilterListItem item);
   }
 
   private class RefreshReceiver extends BroadcastReceiver {