added a setting for 0-key double press function

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) {