From 283bf7de6bc6a439df306466d1cea4af08218c19 Mon Sep 17 00:00:00 2001
From: Dimo Karaivanov <doftor.livain@gmail.com>
Date: Wed, 7 Dec 2022 17:33:06 +0200
Subject: [PATCH] no more unnecessary throtling of the hardware backspace key

---
 .../github/sspanak/tt9/ime/KeyPadHandler.java | 41 ++++---------------
 .../sspanak/tt9/ime/SoftKeyHandler.java       | 17 +++++++-
 .../github/sspanak/tt9/ime/TraditionalT9.java |  5 ++-
 3 files changed, 28 insertions(+), 35 deletions(-)

diff --git a/src/io/github/sspanak/tt9/ime/KeyPadHandler.java b/src/io/github/sspanak/tt9/ime/KeyPadHandler.java
index 9ffec7ed..e8e26e16 100644
--- a/src/io/github/sspanak/tt9/ime/KeyPadHandler.java
+++ b/src/io/github/sspanak/tt9/ime/KeyPadHandler.java
@@ -24,6 +24,8 @@ abstract class KeyPadHandler extends InputMethodService {
 	protected int mEditing = NON_EDIT;
 
 	// temporal key handling
+	private boolean backspaceHandled = false;
+
 	private int ignoreNextKeyUp = 0;
 
 	private int lastKeyCode = 0;
@@ -32,10 +34,6 @@ abstract class KeyPadHandler extends InputMethodService {
 	private int lastNumKeyCode = 0;
 	private int numKeyRepeatCounter = 0;
 
-	// throttling
-	private static final int BACKSPACE_DEBOUNCE_TIME = 80;
-	private long lastBackspaceCall = 0;
-
 
 	/**
 	 * Main initialization of the input method component. Be sure to call to
@@ -135,18 +133,11 @@ abstract class KeyPadHandler extends InputMethodService {
 //		Logger.d("onKeyDown", "Key: " + event + " repeat?: " + event.getRepeatCount() + " long-time: " + event.isLongPress());
 
 		// "backspace" key must repeat its function, when held down, so we handle it in a special way
-		// Also dialer fields seem to handle backspace on their own and we must ignore it,
-		// otherwise, keyDown race condition occur for all keys.
-		if (mEditing != EDITING_DIALER && keyCode == settings.getKeyBackspace()) {
-			boolean isThereTextBefore = InputFieldHelper.isThereText(currentInputConnection);
-			boolean backspaceHandleStatus = handleBackspaceHold();
-
-			// Allow BACK key to function as back when there is no text
-			if (keyCode == KeyEvent.KEYCODE_BACK) {
-				return isThereTextBefore;
-			} else {
-				return backspaceHandleStatus;
-			}
+		if (keyCode == settings.getKeyBackspace()) {
+			// When there is no more text, allow "Back" key to function normally, not to block navigation.
+			// All other keys are blocked, unless it turns out it is annoying this way.
+			backspaceHandled = onBackspace() || keyCode != KeyEvent.KEYCODE_BACK;
+			return backspaceHandled;
 		}
 
 		// In numeric fields, we do not want to handle anything, but "backspace"
@@ -249,11 +240,7 @@ abstract class KeyPadHandler extends InputMethodService {
 
 //		Logger.d("onKeyUp", "Key: " + keyCode + " repeat?: " + event.getRepeatCount());
 
-		if (
-			mEditing != EDITING_DIALER // dialer fields seem to handle backspace on their own
-			&& keyCode == settings.getKeyBackspace()
-			&& InputFieldHelper.isThereText(currentInputConnection)
-		) {
+		if (backspaceHandled && keyCode == settings.getKeyBackspace()) {
 			return true;
 		}
 
@@ -300,18 +287,6 @@ abstract class KeyPadHandler extends InputMethodService {
 	}
 
 
-	protected boolean handleBackspaceHold() {
-		if (System.currentTimeMillis() - lastBackspaceCall < BACKSPACE_DEBOUNCE_TIME) {
-			return true;
-		}
-
-		boolean handled = onBackspace();
-		lastBackspaceCall = System.currentTimeMillis();
-
-		return handled;
-	}
-
-
 	private boolean handleSpecialFunctionKey(int keyCode, boolean hold) {
 		if (keyCode == settings.getKeyAddWord() * (hold ? -1 : 1)) {
 			return onKeyAddWord();
diff --git a/src/io/github/sspanak/tt9/ime/SoftKeyHandler.java b/src/io/github/sspanak/tt9/ime/SoftKeyHandler.java
index 51aff3f2..01064ba1 100644
--- a/src/io/github/sspanak/tt9/ime/SoftKeyHandler.java
+++ b/src/io/github/sspanak/tt9/ime/SoftKeyHandler.java
@@ -17,6 +17,9 @@ class SoftKeyHandler implements View.OnTouchListener {
 	private final TraditionalT9 tt9;
 	private View view = null;
 
+	private static final int BACKSPACE_DEBOUNCE_TIME = 40;
+	private long lastBackspaceCall = 0;
+
 	public SoftKeyHandler(TraditionalT9 tt9) {
 		this.tt9 = tt9;
 
@@ -101,6 +104,18 @@ class SoftKeyHandler implements View.OnTouchListener {
 	}
 
 
+	protected boolean handleBackspaceHold() {
+		if (System.currentTimeMillis() - lastBackspaceCall < BACKSPACE_DEBOUNCE_TIME) {
+			return true;
+		}
+
+		boolean handled = tt9.onBackspace();
+		lastBackspaceCall = System.currentTimeMillis();
+
+		return handled;
+	}
+
+
 	@Override
 	public boolean onTouch(View view, MotionEvent event) {
 		int action = event.getAction();
@@ -117,7 +132,7 @@ class SoftKeyHandler implements View.OnTouchListener {
 		}
 
 		if (buttonId == R.id.main_right && action == MotionEvent.AXIS_PRESSURE) {
-			return tt9.handleBackspaceHold();
+			return handleBackspaceHold();
 		}
 
 		return false;
diff --git a/src/io/github/sspanak/tt9/ime/TraditionalT9.java b/src/io/github/sspanak/tt9/ime/TraditionalT9.java
index d997aee8..7f713e2a 100644
--- a/src/io/github/sspanak/tt9/ime/TraditionalT9.java
+++ b/src/io/github/sspanak/tt9/ime/TraditionalT9.java
@@ -130,7 +130,10 @@ public class TraditionalT9 extends KeyPadHandler {
 
 
 	public boolean onBackspace() {
-		if (!InputFieldHelper.isThereText(currentInputConnection)) {
+		// 1. Dialer fields seem to handle backspace on their own and we must ignore it,
+		// otherwise, keyDown race condition occur for all keys.
+		// 2. Allow the assigned key to function normally, when there is no text (e.g. "Back" navigates back)
+		if (mEditing == EDITING_DIALER || !InputFieldHelper.isThereText(currentInputConnection)) {
 			Logger.d("onBackspace", "backspace ignored");
 			mInputMode.reset();
 			return false;