Added option to enable Android's undo manager

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

@@ -22,6 +22,7 @@ package eu.faircode.email;
 import android.content.ClipData;
 import android.content.ClipboardManager;
 import android.content.Context;
+import android.content.SharedPreferences;
 import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.os.Build;
@@ -44,6 +45,7 @@ import android.view.inputmethod.InputConnection;
 import androidx.core.view.inputmethod.EditorInfoCompat;
 import androidx.core.view.inputmethod.InputConnectionCompat;
 import androidx.core.view.inputmethod.InputContentInfoCompat;
+import androidx.preference.PreferenceManager;
 
 import org.jsoup.nodes.Document;
 
@@ -79,16 +81,17 @@ public class EditTextCompose extends FixedEditText {
     void init(Context context) {
         Helper.setKeyboardIncognitoMode(this, context);
 
-        if (BuildConfig.DEBUG &&
+        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
+        boolean undo_manager = prefs.getBoolean("undo_manager", false);
+
+        if (undo_manager &&
                 Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
             setCustomInsertionActionModeCallback(new ActionMode.Callback() {
                 @Override
                 public boolean onCreateActionMode(ActionMode mode, Menu menu) {
-                    boolean undo = can(android.R.id.undo);
+                    if (can(android.R.id.undo))
-                    boolean redo = can(android.R.id.redo);
-                    if (undo)
                         menu.add(Menu.CATEGORY_ALTERNATIVE, R.string.title_undo, 1, R.string.title_undo);
-                    if (redo)
+                    if (can(android.R.id.redo))
                         menu.add(Menu.CATEGORY_ALTERNATIVE, R.string.title_redo, 2, R.string.title_redo);
                     return true;
                 }

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

@@ -145,6 +145,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
     private TextView tvChunkSize;
     private SeekBar sbChunkSize;
     private ImageButton ibSqliteCache;
+    private SwitchCompat swUndoManager;
     private SwitchCompat swWebViewLegacy;
     private SwitchCompat swModSeq;
     private SwitchCompat swExpunge;
@@ -190,7 +191,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             "experiments", "crash_reports", "cleanup_attachments",
             "protocol", "debug", "log_level", "test1", "test2", "test3", "test4", "test5",
             "query_threads", "wal", "checkpoints", "sqlite_cache",
-            "chunk_size", "webview_legacy",
+            "chunk_size", "undo_manager", "webview_legacy",
             "use_modseq", "perform_expunge", "uid_expunge",
             "auth_plain", "auth_login", "auth_ntlm", "auth_sasl",
             "keep_alive_poll", "empty_pool", "idle_done",
@@ -290,6 +291,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         ibSqliteCache = view.findViewById(R.id.ibSqliteCache);
         tvChunkSize = view.findViewById(R.id.tvChunkSize);
         sbChunkSize = view.findViewById(R.id.sbChunkSize);
+        swUndoManager = view.findViewById(R.id.swUndoManager);
         swWebViewLegacy = view.findViewById(R.id.swWebViewLegacy);
         swModSeq = view.findViewById(R.id.swModSeq);
         swExpunge = view.findViewById(R.id.swExpunge);
@@ -884,6 +886,13 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             }
         });
 
+        swUndoManager.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("undo_manager", checked).apply();
+            }
+        });
+
         swWebViewLegacy.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
             @Override
             public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
@@ -1444,6 +1453,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
         tvChunkSize.setText(getString(R.string.title_advanced_chunk_size, chunk_size));
         sbChunkSize.setProgress(chunk_size);
 
+        swUndoManager.setChecked(prefs.getBoolean("undo_manager", false));
         swWebViewLegacy.setChecked(prefs.getBoolean("webview_legacy", false));
         swModSeq.setChecked(prefs.getBoolean("use_modseq", true));
         swExpunge.setChecked(prefs.getBoolean("perform_expunge", true));

app/src/main/res/layout/fragment_options_misc.xml

@@ -842,6 +842,18 @@
                     app:layout_constraintStart_toStartOf="parent"
                     app:layout_constraintTop_toBottomOf="@id/tvChunkSize" />
 
+                <androidx.appcompat.widget.SwitchCompat
+                    android:id="@+id/swUndoManager"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_marginTop="12dp"
+                    android:checked="true"
+                    android:text="@string/title_advanced_undo_manager"
+                    app:layout_constraintEnd_toEndOf="parent"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toBottomOf="@id/sbChunkSize"
+                    app:switchPadding="12dp" />
+
                 <androidx.appcompat.widget.SwitchCompat
                     android:id="@+id/swWebViewLegacy"
                     android:layout_width="0dp"
@@ -851,7 +863,7 @@
                     android:text="@string/title_advanced_webview_legacy"
                     app:layout_constraintEnd_toEndOf="parent"
                     app:layout_constraintStart_toStartOf="parent"
-                    app:layout_constraintTop_toBottomOf="@id/sbChunkSize"
+                    app:layout_constraintTop_toBottomOf="@id/swUndoManager"
                     app:switchPadding="12dp" />
 
                 <androidx.appcompat.widget.SwitchCompat

app/src/main/res/values/strings.xml

@@ -686,6 +686,7 @@
     <string name="title_advanced_checkpoints" translatable="false">Checkpoints</string>
     <string name="title_advanced_sqlite_cache" translatable="false">Sqlite cache: %1$s %% - %2$s</string>
     <string name="title_advanced_chunk_size" translatable="false">Chunk size: %1$d</string>
+    <string name="title_advanced_undo_manager" translatable="false">Use Android\'s undo manager</string>
     <string name="title_advanced_webview_legacy" translatable="false">Old WebView behavior</string>
     <string name="title_advanced_modseq" translatable="false">MODSEQ</string>
     <string name="title_advanced_expunge" translatable="false">AUTO EXPUNGE</string>