added a setting for 0-key double press function

res/values-bg/strings.xml

@@ -50,4 +50,7 @@
 	<string name="pref_category_predictive_mode">Подсказващ режим</string>
 	<string name="dictionary_missing_go_load_it">Няма речник за език „%1$s“. Заредете го в Настройки.</string>
 	<string name="pref_category_keypad">Клавиатура</string>
+	<string name="pref_double_zero_char">Символ при двойно натисната \"0\"</string>
+	<string name="char_newline">Нов ред</string>
+	<string name="char_space">Интервал</string>
 </resources>

res/values-de/strings.xml

@@ -22,4 +22,6 @@
 	<string name="dictionary_not_found">Wird nicht geladen. Wörterbuch für \"%1$s\" nicht gefunden.</string>
 	<string name="dictionary_loading_indeterminate">Lade Wörterbuch</string>
 	<string name="pref_category_keypad">Tastenfeld</string>
+	<string name="char_space">Leerzeichen</string>
+	<string name="char_newline">Neue Zeile</string>
 </resources>

res/values-fr/strings.xml

@@ -41,4 +41,6 @@
 	<string name="dictionary_missing_go_load_it">Pas de dictionnaire pour langue «%1$s». Veuillez le charger à l\'écran Paramètres.</string>
 	<string name="add_word_invalid_language">Impossible d\'ajouter un mot, si aucune langue n\'est choisie.</string>
 	<string name="pref_category_keypad">Clavier</string>
+	<string name="char_space">Espace</string>
+	<string name="char_newline">Nouvelle ligne</string>
 </resources>

res/values-it/strings.xml

@@ -28,5 +28,7 @@
 	<string name="dictionary_loading_indeterminate">Caricamento del dizionario</string>
 	<string name="dictionary_load_cancelled">Caricamento annullato.</string>
 	<string name="pref_category_keypad">Tastiera</string>
+	<string name="char_space">Spazio</string>
+	<string name="char_newline">Nuova riga</string>
 </resources>
 

res/values-nl/strings.xml

@@ -22,4 +22,6 @@
 	<string name="dictionary_truncated">Woordenboek succesvol gewist.</string>
 	<string name="dictionary_loading_indeterminate">Woordenboek laden</string>
 	<string name="pref_category_keypad">Toetsenbord</string>
+	<string name="char_space">Spatie</string>
+	<string name="char_newline">Nieuwe regel</string>
 </resources>

res/values-ru/strings.xml

@@ -31,4 +31,6 @@
 	<string name="dictionary_load_cancelled">Загрузка отменена.</string>
 	<string name="pref_category_predictive_mode">Режим подсказки</string>
 	<string name="pref_category_keypad">Клавиатура</string>
+	<string name="char_space">Пробел</string>
+	<string name="char_newline">Новая строка</string>
 </resources>

res/values-uk/strings.xml

@@ -28,4 +28,6 @@
 	<string name="dictionary_loading_indeterminate">Завантаження словника</string>
 	<string name="dictionary_load_cancelled">Завантаження скасовано.</string>
 	<string name="pref_category_keypad">Клавіатура</string>
+	<string name="char_space">Пробіл</string>
+	<string name="char_newline">Новий рядок</string>
 </resources>

res/values/strings.xml

@@ -27,7 +27,8 @@
 	<string name="pref_auto_text_case_summary">Automatically start sentences with a capital letter.</string>
 	<string name="pref_choose_languages">Languages</string>
 	<string name="pref_dark_theme">Dark Theme</string>
-	<string name="pref_show_soft_function_keys">Show on-screen keys</string>
+	<string name="pref_double_zero_char">Character for 0-key Double Press</string>
+	<string name="pref_show_soft_function_keys">Show On-Screen Keys</string>
 	<string name="pref_help">Help</string>
 
 	<string name="dictionary_cancel_load">Cancel loading</string>
@@ -64,4 +65,8 @@
 	<string name="key_menu" translatable="false">Menu</string>
 	<string name="key_pound" translatable="false">#</string>
 	<string name="key_star" translatable="false">✱</string>
+
+	<string name="char_dot" translatable="false">.</string>
+	<string name="char_newline">New Line</string>
+	<string name="char_space">Space</string>
 </resources>

res/xml/prefs.xml

@@ -76,6 +76,13 @@
 			app:summary="@string/pref_auto_text_case_summary"
 			app:title="@string/pref_auto_text_case" />
 
+		<DropDownPreference
+			app:defaultValue=" "
+			app:iconSpaceReserved="false"
+			app:key="pref_double_zero_char"
+			app:layout="@layout/pref_dropdown"
+			app:title="@string/pref_double_zero_char" />
+
 	</PreferenceCategory>
 
 	<PreferenceCategory

src/io/github/sspanak/tt9/ime/modes/ModePredictive.java

@@ -87,9 +87,9 @@ public class ModePredictive extends InputMode {
 			reset();
 			word = String.valueOf(key);
 		} else if (key == 0 && repeat > 0) {
-			// repeat "0" to type spaces
+			// repeat "0" is a shortcut for the preferred character (default: space)
 			reset();
-			word = " ";
+			word = settings.getDoubleZeroChar();
 		} else {
 			// words
 			super.reset();

src/io/github/sspanak/tt9/preferences/SettingsStore.java

@@ -208,6 +208,7 @@ public class SettingsStore {
 
 	public boolean getAutoSpace() { return prefs.getBoolean("auto_space", false); }
 	public boolean getAutoTextCase() { return prefs.getBoolean("auto_text_case", true); }
+	public String getDoubleZeroChar() { return prefs.getString("pref_double_zero_char", " "); }
 
 
 	/************* internal settings *************/

src/io/github/sspanak/tt9/preferences/items/ItemSelectZeroKeyCharacter.java

@@ -0,0 +1,67 @@
+package io.github.sspanak.tt9.preferences.items;
+
+import android.content.Context;
+import android.content.res.Resources;
+
+import androidx.preference.DropDownPreference;
+
+import java.util.LinkedHashMap;
+
+import io.github.sspanak.tt9.Logger;
+import io.github.sspanak.tt9.R;
+
+public class ItemSelectZeroKeyCharacter {
+	public static final String NAME = "pref_double_zero_char";
+
+	private final DropDownPreference item;
+	private final LinkedHashMap<String, String> KEYS = new LinkedHashMap<>();
+
+	public ItemSelectZeroKeyCharacter(DropDownPreference dropDown, Context context) {
+		this.item = dropDown;
+
+		Resources resources = context.getResources();
+
+		KEYS.put(" ", resources.getString(R.string.char_space));
+		KEYS.put("\n", resources.getString(R.string.char_newline));
+		KEYS.put(".", resources.getString(R.string.char_dot));
+	}
+
+
+	public ItemSelectZeroKeyCharacter populate() {
+		if (item == null) {
+			Logger.w("tt9/ItemSelectZeroKeyChar.populate", "Cannot populate a NULL item. Ignoring.");
+			return this;
+		}
+
+		item.setEntries(KEYS.values().toArray(new CharSequence[0]));
+		item.setEntryValues(KEYS.keySet().toArray(new CharSequence[0]));
+		previewSelection(item.getValue());
+
+		return this;
+	}
+
+
+	public ItemSelectZeroKeyCharacter activate() {
+		if (item == null) {
+			Logger.w("tt9/ItemSelectZeroKeyChar.activate", "Cannot set a click listener a NULL item. Ignoring.");
+			return this;
+		}
+
+		item.setOnPreferenceChangeListener((preference, newChar) -> {
+			((DropDownPreference) preference).setValue(newChar.toString());
+			previewSelection(newChar.toString());
+			return true;
+		});
+
+		return this;
+	}
+
+
+	private void previewSelection(String newChar) {
+		if (item == null) {
+			return;
+		}
+
+		item.setSummary(KEYS.get(newChar));
+	}
+}

src/io/github/sspanak/tt9/preferences/screens/MainSettingsScreen.java

@@ -6,6 +6,7 @@ import io.github.sspanak.tt9.BuildConfig;
 import io.github.sspanak.tt9.R;
 import io.github.sspanak.tt9.preferences.items.ItemLoadDictionary;
 import io.github.sspanak.tt9.preferences.items.ItemSelectLanguage;
+import io.github.sspanak.tt9.preferences.items.ItemSelectZeroKeyCharacter;
 import io.github.sspanak.tt9.preferences.items.ItemToggleDarkTheme;
 import io.github.sspanak.tt9.preferences.items.ItemTruncateDictionary;
 import io.github.sspanak.tt9.preferences.PreferencesActivity;
@@ -33,9 +34,10 @@ public class MainSettingsScreen extends BaseScreenFragment {
 
 	@Override
 	public void onCreate() {
-		createDictionarySection();
-		createAppearanceSection();
 		createAboutSection();
+		createAppearanceSection();
+		createDictionarySection();
+		createPredictiveModeSection();
 	}
 
 
@@ -70,6 +72,11 @@ public class MainSettingsScreen extends BaseScreenFragment {
 	}
 
 
+	private void createPredictiveModeSection() {
+		(new ItemSelectZeroKeyCharacter(findPreference(ItemSelectZeroKeyCharacter.NAME), activity)).populate().activate();
+	}
+
+
 	private void createAboutSection() {
 		Preference vi = findPreference("version_info");
 		if (vi != null) {