Added menu item to disable folders for accounts

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

@@ -79,6 +79,7 @@ public class AdapterAccount extends RecyclerView.Adapter<AdapterAccount.ViewHold
     private Fragment parentFragment;
     private boolean settings;
     private boolean compact;
+    private boolean show_folders;
 
     private Context context;
     private LifecycleOwner owner;
@@ -92,6 +93,7 @@ public class AdapterAccount extends RecyclerView.Adapter<AdapterAccount.ViewHold
     private int textColorTertiary;
     private boolean debug;
 
+    private List<TupleAccountFolder> all = new ArrayList<>();
     private List<TupleAccountFolder> items = new ArrayList<>();
 
     private NumberFormat NF = NumberFormat.getNumberInstance();
@@ -858,10 +860,11 @@ public class AdapterAccount extends RecyclerView.Adapter<AdapterAccount.ViewHold
         }
     }
 
-    AdapterAccount(final Fragment parentFragment, boolean settings, boolean compact) {
+    AdapterAccount(final Fragment parentFragment, boolean settings, boolean compact, boolean folders) {
         this.parentFragment = parentFragment;
         this.settings = settings;
         this.compact = compact;
+        this.show_folders = folders;
 
         this.context = parentFragment.getContext();
         this.owner = parentFragment.getViewLifecycleOwner();
@@ -897,12 +900,24 @@ public class AdapterAccount extends RecyclerView.Adapter<AdapterAccount.ViewHold
     public void set(@NonNull List<TupleAccountFolder> accounts) {
         Log.i("Set accounts=" + accounts.size());
 
-        if (accounts.size() > 0)
-            TupleAccountFolder.sort(accounts, true, context);
+        this.all = accounts;
 
-        DiffUtil.DiffResult diff = DiffUtil.calculateDiff(new DiffCallback(items, accounts), false);
+        List<TupleAccountFolder> filtered;
+        if (show_folders)
+            filtered = all;
+        else {
+            filtered = new ArrayList<>();
+            for (TupleAccountFolder account : accounts)
+                if (account.folderName == null)
+                    filtered.add(account);
+        }
+
+        if (filtered.size() > 0)
+            TupleAccountFolder.sort(filtered, true, context);
+
+        DiffUtil.DiffResult diff = DiffUtil.calculateDiff(new DiffCallback(items, filtered), false);
 
-        items = accounts;
+        items = filtered;
 
         diff.dispatchUpdatesTo(new ListUpdateCallback() {
             @Override
@@ -938,6 +953,13 @@ public class AdapterAccount extends RecyclerView.Adapter<AdapterAccount.ViewHold
             this.compact = compact;
     }
 
+    void setShowFolders(boolean show_folders) {
+        if (this.show_folders != show_folders) {
+            this.show_folders = show_folders;
+            set(all);
+        }
+    }
+
     private static class DiffCallback extends DiffUtil.Callback {
         private List<TupleAccountFolder> prev = new ArrayList<>();
         private List<TupleAccountFolder> next = new ArrayList<>();

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

@@ -58,12 +58,9 @@ import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
 import com.google.android.material.floatingactionbutton.FloatingActionButton;
 import com.google.android.material.snackbar.Snackbar;
 
-import java.text.Collator;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.Comparator;
 import java.util.List;
-import java.util.Locale;
 import java.util.Objects;
 
 public class FragmentAccounts extends FragmentBase {
@@ -72,6 +69,7 @@ public class FragmentAccounts extends FragmentBase {
     private boolean cards;
     private boolean dividers;
     private boolean compact;
+    private boolean show_folders;
 
     private ViewGroup view;
     private SwipeRefreshLayout swipeRefresh;
@@ -97,6 +95,7 @@ public class FragmentAccounts extends FragmentBase {
         cards = prefs.getBoolean("cards", true);
         dividers = prefs.getBoolean("dividers", true);
         compact = prefs.getBoolean("compact_accounts", false) && !settings;
+        show_folders = prefs.getBoolean("folders_accounts", true) && !settings;
     }
 
     @Override
@@ -222,7 +221,7 @@ public class FragmentAccounts extends FragmentBase {
         };
         rvAccount.addItemDecoration(categoryDecorator);
 
-        adapter = new AdapterAccount(this, settings, compact);
+        adapter = new AdapterAccount(this, settings, compact, show_folders);
         rvAccount.setAdapter(adapter);
 
         fab.setOnClickListener(new View.OnClickListener() {
@@ -359,6 +358,8 @@ public class FragmentAccounts extends FragmentBase {
         menu.findItem(R.id.menu_outbox).setVisible(!settings);
         menu.findItem(R.id.menu_compact).setChecked(compact);
         menu.findItem(R.id.menu_compact).setVisible(!settings);
+        menu.findItem(R.id.menu_show_folders).setChecked(show_folders);
+        menu.findItem(R.id.menu_show_folders).setVisible(!settings);
         menu.findItem(R.id.menu_theme).setVisible(!settings);
         menu.findItem(R.id.menu_force_sync).setVisible(!settings);
 
@@ -380,6 +381,9 @@ public class FragmentAccounts extends FragmentBase {
         } else if (itemId == R.id.menu_compact) {
             onMenuCompact();
             return true;
+        } else if (itemId == R.id.menu_show_folders) {
+            onMenuShowFolders();
+            return true;
         } else if (itemId == R.id.menu_theme) {
             onMenuTheme();
             return true;
@@ -433,6 +437,16 @@ public class FragmentAccounts extends FragmentBase {
         });
     }
 
+    private void onMenuShowFolders() {
+        show_folders = !show_folders;
+
+        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
+        prefs.edit().putBoolean("folders_accounts", show_folders).apply();
+
+        invalidateOptionsMenu();
+        adapter.setShowFolders(show_folders);
+    }
+
     private void onMenuTheme() {
         new FragmentDialogTheme().show(getParentFragmentManager(), "messages:theme");
     }

app/src/main/res/menu/menu_accounts.xml

@@ -27,6 +27,12 @@
             android:title="@string/title_compact"
             app:showAsAction="never" />
 
+        <item
+            android:id="@+id/menu_show_folders"
+            android:checkable="true"
+            android:title="@string/page_folders"
+            app:showAsAction="never" />
+
         <item
             android:id="@+id/menu_theme"
             android:title="@string/title_setup_theme"