Use transparent keys for extension keyboard.

res/drawable/btn_keyboard_key_fulltrans.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (C) 2010 The Android Open Source Project
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <!-- Normal keys -->
+
+    <item android:state_pressed="true"
+          android:drawable="@drawable/btn_keyboard_key_fulltrans_pressed" />
+    <item
+          android:drawable="@drawable/btn_keyboard_key_fulltrans_normal" />
+          
+</selector>

res/layout/input_trans.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/* 
+**
+** Copyright 2010, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License"); 
+** you may not use this file except in compliance with the License. 
+** You may obtain a copy of the License at 
+**
+**     http://www.apache.org/licenses/LICENSE-2.0 
+**
+** Unless required by applicable law or agreed to in writing, software 
+** distributed under the License is distributed on an "AS IS" BASIS, 
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
+** See the License for the specific language governing permissions and 
+** limitations under the License.
+*/
+-->
+
+<com.android.inputmethod.latin.LatinKeyboardView
+        xmlns:android="http://schemas.android.com/apk/res/android"
+        android:id="@android:id/keyboardView"
+        android:layout_alignParentBottom="true"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:background="#A0000000"
+        android:keyBackground="@drawable/btn_keyboard_key_fulltrans"
+        />

src/com/android/inputmethod/latin/LatinKeyboardView.java

@@ -171,7 +171,7 @@ public class LatinKeyboardView extends KeyboardView {
             mExtensionPopup.setBackgroundDrawable(null);
             LayoutInflater li = (LayoutInflater) getContext().getSystemService(
                     Context.LAYOUT_INFLATER_SERVICE);
-            mExtension = (LatinKeyboardView) li.inflate(R.layout.input, null);
+            mExtension = (LatinKeyboardView) li.inflate(R.layout.input_trans, null);
             mExtension.setOnKeyboardActionListener((LatinIME) getContext());
             mExtension.setPopupParent(this);
             mExtension.setPopupOffset(0, -windowLocation[1]);