backspace acceleration function

app/src/main/java/io/github/sspanak/tt9/ime/AbstractHandler.java

@@ -11,7 +11,7 @@ import io.github.sspanak.tt9.util.Ternary;
 abstract public class AbstractHandler extends InputMethodService {
 	// hardware key handlers
 	abstract protected Ternary onBack();
-	abstract public boolean onBackspace();
+	abstract public boolean onBackspace(boolean hold);
 	abstract public boolean onHotkey(int keyCode, boolean repeat, boolean validateOnly);
 	abstract protected boolean onNumber(int key, boolean hold, int repeat);
 	abstract public boolean onOK();

app/src/main/java/io/github/sspanak/tt9/ime/KeyPadHandler.java

@@ -60,7 +60,11 @@ abstract class KeyPadHandler extends UiHandler {
 
 		// "backspace" key must repeat its function when held down, so we handle it in a special way
 		if (Key.isBackspace(settings, keyCode)) {
-			if (onBackspace()) {
+			if (
+				(settings.getBackspaceAcceleration() && event.getRepeatCount() > 0 && event.getRepeatCount() % SettingsStore.BACKSPACE_ACCELERATION_HARD_KEY_REPEAT_DEBOUNCE == 0 && onBackspace(true))
+				|| (settings.getBackspaceAcceleration() && event.getRepeatCount() > 0)
+				|| onBackspace(false)
+			) {
 				return Key.setHandled(KeyEvent.KEYCODE_DEL, true);
 			} else {
 				Key.setHandled(KeyEvent.KEYCODE_DEL, false);

app/src/main/java/io/github/sspanak/tt9/ime/TypingHandler.java

@@ -21,6 +21,7 @@ import io.github.sspanak.tt9.ime.modes.InputMode;
 import io.github.sspanak.tt9.ime.modes.ModePredictive;
 import io.github.sspanak.tt9.languages.Language;
 import io.github.sspanak.tt9.languages.LanguageCollection;
+import io.github.sspanak.tt9.preferences.settings.SettingsStore;
 import io.github.sspanak.tt9.ui.UI;
 import io.github.sspanak.tt9.util.Text;
 
@@ -110,7 +111,7 @@ public abstract class TypingHandler extends KeyPadHandler {
 
 
 	@Override
-	public boolean onBackspace() {
+	public boolean onBackspace(boolean hold) {
 		// Dialer fields seem to handle backspace on their own and we must ignore it,
 		// otherwise, keyDown race condition occur for all keys.
 		if (mInputMode.isPassthrough()) {
@@ -125,11 +126,16 @@ public abstract class TypingHandler extends KeyPadHandler {
 		suggestionOps.cancelDelayedAccept();
 		resetKeyRepeat();
 
-		if (mInputMode.onBackspace()) {
+		if (!hold && mInputMode.onBackspace()) {
 			getSuggestions();
 		} else {
 			suggestionOps.commitCurrent(false);
-			super.sendDownUpKeyEvents(KeyEvent.KEYCODE_DEL);
+			mInputMode.reset();
+
+			int repeats = hold ? Math.min(Math.max(textField.getWordBeforeCursorLength(), 1), SettingsStore.BACKSPACE_ACCELERATION_MAX_CHARS) : 1;
+			for (int i = repeats; i > 0; i--) {
+				super.sendDownUpKeyEvents(KeyEvent.KEYCODE_DEL);
+			}
 		}
 
 		return true;

app/src/main/java/io/github/sspanak/tt9/ime/helpers/TextField.java

@@ -104,6 +104,26 @@ public class TextField extends InputField {
 	}
 
 
+	/**
+	 * Returns the length of the word before the cursor. If the cursor is inside a word, 0 is returned,
+	 * because there is no full word before it. The scanning length is up to the maximum returned by
+	 * getTextBeforeCursor().
+	 */
+	public int getWordBeforeCursorLength() {
+		if (getTextAfterCursor(1).startsWithWord()) {
+			return 0;
+		}
+
+		String before = getStringBeforeCursor();
+		if (before.isEmpty()) {
+			return 0;
+		}
+
+		int spaceShift = Math.max(before.lastIndexOf(' '), 0);
+		return before.length() - spaceShift;
+	}
+
+
 	/**
 	 * deletePrecedingSpace
 	 * Deletes the preceding space before the given word. The word must be before the cursor.

app/src/main/java/io/github/sspanak/tt9/preferences/settings/SettingsStore.java

@@ -7,6 +7,9 @@ public class SettingsStore extends SettingsUI {
 	public SettingsStore(Context context) { super(context); }
 
 	/************* internal settings *************/
+	public static final int BACKSPACE_ACCELERATION_MAX_CHARS = 10;
+	public static final int BACKSPACE_ACCELERATION_HARD_KEY_REPEAT_DEBOUNCE = 5;
+	public static final int BACKSPACE_ACCELERATION_SOFT_KEY_REPEAT_DEBOUNCE = 7;
 	public final static int CLIPBOARD_PREVIEW_LENGTH = 20;
 	public final static int CUSTOM_WORDS_IMPORT_MAX_LINES = 250;
 	public final static int CUSTOM_WORDS_MAX = 1000;

app/src/main/java/io/github/sspanak/tt9/preferences/settings/SettingsTyping.java

@@ -15,6 +15,10 @@ class SettingsTyping extends SettingsInput {
 		return getAutoTextCase() && prefs.getBoolean("auto_capitals_after_newline", false);
 	}
 
+	public boolean getBackspaceAcceleration() {
+		return prefs.getBoolean("backspace_acceleration", false);
+	}
+
 	public String getDoubleZeroChar() {
 		String character = prefs.getString("pref_double_zero_char", ".");
 

app/src/main/java/io/github/sspanak/tt9/ui/main/keys/SoftBackspaceKey.java

@@ -6,10 +6,12 @@ import android.view.KeyEvent;
 
 import io.github.sspanak.tt9.R;
 import io.github.sspanak.tt9.languages.LanguageKind;
+import io.github.sspanak.tt9.preferences.settings.SettingsStore;
 import io.github.sspanak.tt9.ui.Vibration;
 
 public class SoftBackspaceKey extends SoftKey {
 	private boolean hold;
+	private int repeatCount = 0;
 
 	public SoftBackspaceKey(Context context) {
 		super(context);
@@ -27,12 +29,23 @@ public class SoftBackspaceKey extends SoftKey {
 	final protected boolean handlePress() {
 		super.handlePress();
 		hold = false;
-		return deleteText();
+		repeatCount = 0;
+		return validateTT9Handler() && deleteText();
 	}
 
 	@Override
 	final protected void handleHold() {
 		hold = true;
+
+		if (
+			validateTT9Handler()
+			&& tt9.getSettings().getBackspaceAcceleration()
+			&& ++repeatCount < SettingsStore.BACKSPACE_ACCELERATION_SOFT_KEY_REPEAT_DEBOUNCE
+		) {
+			return;
+		}
+
+		repeatCount = 0;
 		deleteText();
 	}
 
@@ -44,7 +57,7 @@ public class SoftBackspaceKey extends SoftKey {
 	}
 
 	private boolean deleteText() {
-		if (validateTT9Handler() && !tt9.onBackspace()) {
+		if (!tt9.onBackspace(hold && tt9.getSettings().getBackspaceAcceleration())) {
 			// Limited or special numeric field (e.g. formatted money or dates) cannot always return
 			// the text length, therefore onBackspace() seems them as empty and does nothing. This results
 			// in fallback to the default hardware key action. Here we simulate the hardware BACKSPACE.

app/src/main/java/io/github/sspanak/tt9/util/Text.java

@@ -95,9 +95,6 @@ public class Text extends TextTools {
 	}
 
 
-
-
-
 	public boolean startsWithWhitespace() {
 		return text != null && !text.isEmpty() && Character.isWhitespace(text.charAt(0));
 	}
@@ -110,6 +107,10 @@ public class Text extends TextTools {
 		return text != null && !text.isEmpty() && Characters.isGraphic(text.charAt(0));
 	}
 
+	public boolean startsWithWord() {
+		return text != null && !text.isEmpty() && Character.isAlphabetic(text.charAt(0));
+	}
+
 	public String subStringEndingWord(boolean keepApostrophe, boolean keepQuote) {
 		if (text == null) {
 			return "";

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

@@ -167,4 +167,6 @@
 	<string name="language_selection_title">Избор на езици</string>
 	<string name="language_selection_search_placeholder">Търси езици</string>
 	<string name="language_selection_words">думи</string>
+	<string name="pref_backspace_acceleration">Бързо изтриване</string>
+	<string name="pref_backspace_acceleration_summary">Изтривай цели думи при задържане на Backspace.\n(Не работи в някои приложения.)</string>
 </resources>

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

@@ -156,4 +156,6 @@
 	<string name="language_selection_title">Sprachen aktivieren</string>
 	<string name="language_selection_search_placeholder">Nach Sprachen suchen</string>
 	<string name="language_selection_words">Wörter</string>
+	<string name="pref_backspace_acceleration">Schnelles Löschen</string>
+	<string name="pref_backspace_acceleration_summary">Ganze Wörter löschen, indem Sie die Rücktaste gedrückt halten.\n(Nicht in allen Apps unterstützt)</string>
 </resources>

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

@@ -165,4 +165,6 @@
 	<string name="language_selection_title">Habilitar idiomas</string>
 	<string name="language_selection_search_placeholder">Buscar idiomas</string>
 	<string name="language_selection_words">palabras</string>
+	<string name="pref_backspace_acceleration">Eliminación rápida</string>
+	<string name="pref_backspace_acceleration_summary">Borrar palabras completas manteniendo presionada la tecla Retroceso.\n(No compatible con algunas aplicaciones)</string>
 </resources>

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

@@ -163,4 +163,6 @@
 	<string name="language_selection_title">Activer les langues</string>
 	<string name="language_selection_search_placeholder">Rechercher des langues</string>
 	<string name="language_selection_words">mots</string>
+	<string name="pref_backspace_acceleration">Suppression rapide</string>
+	<string name="pref_backspace_acceleration_summary">Effacer des mots entiers en maintenant la touche Retour arrière.\n(Non pris en charge dans certaines applications)</string>
 </resources>

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

@@ -155,5 +155,7 @@
 	<string name="language_selection_title">Abilita lingue</string>
 	<string name="language_selection_search_placeholder">Cerca lingue</string>
 	<string name="language_selection_words">parole</string>
+	<string name="pref_backspace_acceleration">Cancellazione rapida</string>
+	<string name="pref_backspace_acceleration_summary">Cancellare intere parole tenendo premuto Backspace.\n(Non supportato in alcune app)</string>
 </resources>
 

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

@@ -168,4 +168,6 @@
 	<string name="language_selection_title">הפעל שפות</string>
 	<string name="language_selection_search_placeholder">חיפוש שפות</string>
 	<string name="language_selection_words">מילים</string>
+	<string name="pref_backspace_acceleration">מחיקה מהירה</string>
+	<string name="pref_backspace_acceleration_summary">למחוק מילים שלמות על ידי החזקת מקש Backspace.\n(לא נתמך בחלק מהאפליקציות)</string>
 </resources>

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

@@ -174,4 +174,6 @@
 	<string name="language_selection_title">Įjungti kalbas</string>
 	<string name="language_selection_search_placeholder">Ieškoti kalbų</string>
 	<string name="language_selection_words">žodžių</string>
+	<string name="pref_backspace_acceleration">Greitas ištrynimas</string>
+	<string name="pref_backspace_acceleration_summary">Ištrinti visus žodžius laikant klavišą Backspace.\n(Nepalaikoma kai kuriose programėlėse)</string>
 </resources>

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

@@ -154,4 +154,6 @@
 	<string name="language_selection_title">Talen inschakelen</string>
 	<string name="language_selection_search_placeholder">Zoeken naar talen</string>
 	<string name="language_selection_words">woorden</string>
+	<string name="pref_backspace_acceleration">Snel verwijderen</string>
+	<string name="pref_backspace_acceleration_summary">Hele woorden wissen door Backspace ingedrukt te houden.\n(Niet ondersteund in sommige apps)</string>
 </resources>

app/src/main/res/values-pt-rBR/strings.xml

@@ -36,9 +36,9 @@
 	<string name="pref_abc_auto_accept_slow">Lento</string>
 	<string name="pref_alternative_suggestion_scrolling">Método alternativo de rolagem de sugestões</string>
 	<string name="pref_alternative_suggestion_scrolling_summary">Ative se às vezes não conseguir ver todas as sugestões ou tiver problemas para rolá-las (Android 9 ou mais antigo).</string>
-	<string name="pref_auto_space">Espaçamento Automático</string>
+	<string name="pref_auto_space">Espaçamento automático</string>
 	<string name="pref_auto_space_summary">Insere um espaçamento após ponto final.</string>
-	<string name="pref_auto_text_case">Maiúsculas Automáticas</string>
+	<string name="pref_auto_text_case">Maiúsculas automáticas</string>
 	<string name="pref_auto_text_case_summary">Iniciar automaticamente as frases com letras maiúsculas.</string>
 	<string name="pref_auto_capitals_after_newline">Letras maiúsculas automáticas em cada linha</string>
 	<string name="pref_auto_capitals_after_newline_summary">Começar cada linha com uma letra maiúscula, mesmo que esteja no meio de uma frase.</string>
@@ -168,4 +168,6 @@
 	<string name="language_selection_title">Habilitar idiomas</string>
 	<string name="language_selection_search_placeholder">Buscar por idiomas</string>
 	<string name="language_selection_words">palavras</string>
+	<string name="pref_backspace_acceleration">Exclusão rápida</string>
+	<string name="pref_backspace_acceleration_summary">Apagar palavras inteiras segurando a tecla Backspace.\n(Não suportado em alguns aplicativos)</string>
 </resources>

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

@@ -165,4 +165,6 @@
 	<string name="language_selection_title">Включить языки</string>
 	<string name="language_selection_search_placeholder">Поиск языков</string>
 	<string name="language_selection_words">слов</string>
+	<string name="pref_backspace_acceleration">Быстрое удаление</string>
+	<string name="pref_backspace_acceleration_summary">Стирать целые слова, удерживая клавишу Backspace.\n(Не поддерживается в некоторых приложениях)</string>
 </resources>

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

@@ -168,4 +168,6 @@
 	<string name="language_selection_title">Dilleri etkinleştir</string>
 	<string name="language_selection_search_placeholder">Diller için arama</string>
 	<string name="language_selection_words">kelime</string>
+	<string name="pref_backspace_acceleration">Hızlı Silme</string>
+	<string name="pref_backspace_acceleration_summary">Geri tuşunu basılı tutarak tüm kelimeleri silin.\n(Bazı uygulamalarda desteklenmez)</string>
 </resources>

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

@@ -176,4 +176,6 @@
 	<string name="language_selection_title">Увімкнути мови</string>
 	<string name="language_selection_search_placeholder">Пошук мов</string>
 	<string name="language_selection_words">слів</string>
+	<string name="pref_backspace_acceleration">Швидке видалення</string>
+	<string name="pref_backspace_acceleration_summary">Видаляти цілі слова, утримуючи клавішу Backspace.\n(Не підтримується в деяких додатках)</string>
 </resources>

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

@@ -23,6 +23,7 @@
 	<string name="add_word_success">\"%1$s\" added.</string>
 	<string name="add_word_title">Add Word</string>
 
+
 	<string name="commands_select_command">Select a Command</string>
 
 	<string name="pref_category_about">About</string>
@@ -52,6 +53,8 @@
 	<string name="pref_auto_text_case_summary">Automatically start sentences with a capital letter.</string>
 	<string name="pref_auto_capitals_after_newline">Automatically Capitalize Every Line</string>
 	<string name="pref_auto_capitals_after_newline_summary">Start every line with a capital letter, even it is in the middle of a sentence.</string>
+	<string name="pref_backspace_acceleration">Fast Delete</string>
+	<string name="pref_backspace_acceleration_summary">Erase entire words by holding Backspace.\n(Not supported in some apps)</string>
 	<string name="pref_choose_languages">Languages</string>
 	<string name="pref_dark_theme">Dark Theme</string>
 	<string name="pref_dark_theme_yes">Yes</string>

app/src/main/res/xml/prefs_screen_keypad.xml

@@ -14,6 +14,14 @@
 			app:title="@string/pref_haptic_feedback"
 			app:summary="@string/pref_haptic_feedback_summary"/>
 
+	<PreferenceCategory android:title="@string/function_backspace">
+		<SwitchPreferenceCompat
+			app:defaultValue="false"
+			app:key="backspace_acceleration"
+			app:title="@string/pref_backspace_acceleration"
+			app:summary="@string/pref_backspace_acceleration_summary" />
+	</PreferenceCategory>
+
 	<PreferenceCategory android:title="@string/pref_category_predictive_mode">
 
 		<SwitchPreferenceCompat