[CB14] Implement backspace in the combiner chain

Bug: 13622107
Bug: 13406701
Change-Id: I0023b398c4451253f9f717e2bd990b8a054004bc

2 files changed, 16 insertions, 2 deletions

diff --git a/java/src/com/android/inputmethod/event/CombinerChain.java b/java/src/com/android/inputmethod/event/CombinerChain.java
index 5ca9842c1..8b59dc52a 100644
--- a/java/src/com/android/inputmethod/event/CombinerChain.java
+++ b/java/src/com/android/inputmethod/event/CombinerChain.java
@@ -17,7 +17,9 @@
 package com.android.inputmethod.event;
 
 import android.text.SpannableStringBuilder;
+import android.text.TextUtils;
 
+import com.android.inputmethod.latin.Constants;
 import com.android.inputmethod.latin.utils.CollectionUtils;
 
 import java.util.ArrayList;
@@ -84,7 +86,19 @@ public class CombinerChain {
             }
         }
         if (null != event) {
-            mCombinedText.append(event.getTextToCommit());
+            // TODO: figure out the generic way of doing this
+            if (Constants.CODE_DELETE == event.mKeyCode) {
+                final int length = mCombinedText.length();
+                if (length > 0) {
+                    final int lastCodePoint = mCombinedText.codePointBefore(length);
+                    mCombinedText.delete(length - Character.charCount(lastCodePoint), length);
+                }
+            } else {
+                final CharSequence textToCommit = event.getTextToCommit();
+                if (!TextUtils.isEmpty(textToCommit)) {
+                    mCombinedText.append(textToCommit);
+                }
+            }
         }
         mStateFeedback.clear();
         for (int i = mCombiners.size() - 1; i >= 0; --i) {
diff --git a/java/src/com/android/inputmethod/event/Event.java b/java/src/com/android/inputmethod/event/Event.java
index 2bfe0732d..646590948 100644
--- a/java/src/com/android/inputmethod/event/Event.java
+++ b/java/src/com/android/inputmethod/event/Event.java
@@ -229,9 +229,9 @@ public class Event {
         switch (mType) {
         case EVENT_MODE_KEY:
         case EVENT_NOT_HANDLED:
+        case EVENT_TOGGLE:
             return "";
         case EVENT_INPUT_KEYPRESS:
-        case EVENT_TOGGLE:
             return StringUtils.newSingleCodePointString(mCodePoint);
         case EVENT_GESTURE:
         case EVENT_SOFTWARE_GENERATED_STRING: