Fixed swipe refresh on fast scroll

FAQ.md

@@ -31,7 +31,6 @@ For authorizing:
 * A [bug in Android](https://issuetracker.google.com/issues/62427912) "*... ActivityRecord not found for ...*" sometimes causes a crash after updating FairEmail. Reinstalling ([source](https://stackoverflow.com/questions/46309428/android-activitythread-reportsizeconfigurations-causes-app-to-freeze-with-black)) migth fix the problem.
 * Encryption with [YubiKey](https://www.yubico.com/) results into an infinite loop. FairEmail follows the latest version of the [OpenKeychain API](https://github.com/open-keychain/openpgp-api), so this is likely being caused by an external bug.
 * A bug in the Nova Launcher lets FairEmail crash with a *java.lang.StackOverflowError* when the Nova Launcher has access to the accessibility service.
-* Fast scrolling sometimes triggers a swipe refresh. Unfortunately, there is no way to detect that a fast scroll is in progress and to disable swipe refreshing.
 
 ## Planned features
 

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

@@ -192,7 +192,6 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
 
     private boolean date;
     private boolean threading;
-    private boolean pull;
     private boolean swipenav;
     private boolean autoscroll;
     private boolean actionbar;
@@ -309,11 +308,6 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
 
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
 
-        if (viewType == AdapterMessage.ViewType.UNIFIED || viewType == AdapterMessage.ViewType.FOLDER)
-            pull = prefs.getBoolean("pull", true);
-        else
-            pull = false;
-
         swipenav = prefs.getBoolean("swipenav", true);
         autoscroll = (prefs.getBoolean("autoscroll", false) || viewType == AdapterMessage.ViewType.THREAD);
         date = prefs.getBoolean("date", true);
@@ -900,12 +894,24 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                         fabMore.show();
                     else
                         fabMore.hide();
-                    updateSwipeRefresh();
                 }
             });
         }
 
-        updateSwipeRefresh();
+        swipeRefresh.setOnChildScrollUpCallback(new SwipeRefreshLayout.OnChildScrollUpCallback() {
+            @Override
+            public boolean canChildScrollUp(@NonNull SwipeRefreshLayout parent, @Nullable View child) {
+                if (viewType != AdapterMessage.ViewType.UNIFIED && viewType != AdapterMessage.ViewType.FOLDER)
+                    return true;
+                if (!prefs.getBoolean("pull", true))
+                    return true;
+                if (swiping)
+                    return true;
+                if (selectionTracker != null && selectionTracker.hasSelection())
+                    return true;
+                return rvMessage.canScrollVertically(-1);
+            }
+        });
 
         pgpService = new OpenPgpServiceConnection(getContext(), "org.sufficientlysecure.keychain");
         pgpService.bindToService();
@@ -946,10 +952,6 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
         super.onDestroy();
     }
 
-    private void updateSwipeRefresh() {
-        swipeRefresh.setEnabled(pull && !swiping && (selectionTracker == null || !selectionTracker.hasSelection()));
-    }
-
     private void scrollToVisibleItem(LinearLayoutManager llm, boolean bottom) {
         int pos = llm.findLastVisibleItemPosition();
         if (pos == RecyclerView.NO_POSITION)
@@ -1294,7 +1296,6 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
         public void onSelectedChanged(@Nullable RecyclerView.ViewHolder viewHolder, int actionState) {
             super.onSelectedChanged(viewHolder, actionState);
             swiping = (actionState == ItemTouchHelper.ACTION_STATE_SWIPE);
-            updateSwipeRefresh();
         }
 
         @Override

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

@@ -40,7 +40,7 @@ public class FragmentOptions extends FragmentBase {
     static String[] OPTIONS_RESTART = new String[]{
             "startup", "date", "threading", "avatars", "identicons", "circular", "name_email", "subject_italic", "flags", "preview",
             "addresses", "attachments_alt", "contrast", "monospaced", "autohtml", "autoimages", "actionbar",
-            "pull", "autoscroll", "swipenav", "autoexpand", "autoclose", "autonext",
+            "autoscroll", "swipenav", "autoexpand", "autoclose", "autonext",
             "subscriptions", "debug",
             "biometrics"
     };