Use separate View for key preview backing

Bug: 5246982
Change-Id: Icec4281cb01771909fcece36647ee42ba179118c

java/res/layout/input_view.xml

@@ -25,6 +25,11 @@
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
 >
+    <View
+        android:id="@+id/key_preview_backing"
+        android:layout_width="match_parent"
+        android:layout_height="@dimen/key_preview_backing_height" />
+
     <!-- On tablets, the suggestions strip is centered with horizontal paddings on both sides
          because width of the landscape mode is too long for the suggestions strip. This
          LinearLayout is required to hold the paddings. -->
@@ -33,8 +38,6 @@
         android:orientation="horizontal"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
-        android:minHeight="@dimen/suggestions_view_minimum_height"
-        android:gravity="bottom"
     >
         <View
             android:layout_width="@dimen/suggestions_strip_padding"

java/res/values-land/dimens.xml

@@ -60,7 +60,7 @@
 
     <dimen name="suggestions_strip_height">36dip</dimen>
     <dimen name="more_suggestions_row_height">36dip</dimen>
-    <dimen name="suggestions_view_minimum_height">160sp</dimen>
+    <dimen name="key_preview_backing_height">36dip</dimen>
     <!-- Amount of allowance for selecting keys in a mini popup keyboard by sliding finger. -->
     <!-- popup_key_height x 1.2 -->
     <dimen name="mini_keyboard_slide_allowance">0.336in</dimen>

java/res/values-sw600dp/dimens.xml

@@ -68,6 +68,7 @@
 
     <dimen name="suggestions_strip_height">44dip</dimen>
     <dimen name="more_suggestions_row_height">44dip</dimen>
+    <dimen name="key_preview_backing_height">44dip</dimen>
     <dimen name="suggestions_strip_padding">15.0mm</dimen>
     <dimen name="suggestion_min_width">0.3in</dimen>
     <dimen name="suggestion_padding">12dip</dimen>

java/res/values-sw768dp/dimens.xml

@@ -71,7 +71,7 @@
 
     <dimen name="suggestions_strip_height">44dip</dimen>
     <dimen name="more_suggestions_row_height">44dip</dimen>
-    <dimen name="suggestions_view_minimum_height">200sp</dimen>
+    <dimen name="key_preview_backing_height">44dip</dimen>
     <dimen name="suggestions_strip_padding">15.0mm</dimen>
     <dimen name="suggestion_min_width">46dip</dimen>
     <dimen name="suggestion_padding">8dip</dimen>

java/res/values/dimens.xml

@@ -81,7 +81,7 @@
     <dimen name="more_suggestions_row_height">40dip</dimen>
     <dimen name="more_suggestions_slide_allowance">0.2in</dimen>
     <fraction name="more_suggestions_info_ratio">12%</fraction>
-    <dimen name="suggestions_view_minimum_height">200sp</dimen>
+    <dimen name="key_preview_backing_height">40dip</dimen>
     <dimen name="suggestions_strip_padding">0dip</dimen>
     <dimen name="suggestion_min_width">44dip</dimen>
     <dimen name="suggestion_padding">6dip</dimen>

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

@@ -157,6 +157,7 @@ public class LatinIME extends InputMethodServiceCompatWrapper implements Keyboar
 
     private Settings.Values mSettingsValues;
 
+    private View mKeyPreviewBackingView;
     private View mSuggestionsContainer;
     private int mSuggestionsStripHeight;
     private SuggestionsView mSuggestionsView;
@@ -607,6 +608,7 @@ public class LatinIME extends InputMethodServiceCompatWrapper implements Keyboar
     @Override
     public void setInputView(View view) {
         super.setInputView(view);
+        mKeyPreviewBackingView = view.findViewById(R.id.key_preview_backing);
         mSuggestionsContainer = view.findViewById(R.id.suggestions_container);
         mSuggestionsView = (SuggestionsView) view.findViewById(R.id.suggestions_view);
         if (mSuggestionsView != null)
@@ -945,12 +947,13 @@ public class LatinIME extends InputMethodServiceCompatWrapper implements Keyboar
                     && (needsInputViewShown ? mKeyboardSwitcher.isInputViewShown() : true);
             if (isFullscreenMode()) {
                 // No need to have extra space to show the key preview.
-                mSuggestionsContainer.setMinimumHeight(0);
+                mKeyPreviewBackingView.setVisibility(View.GONE);
                 mSuggestionsContainer.setVisibility(
                         shouldShowSuggestions ? View.VISIBLE : View.GONE);
             } else {
                 // We must control the visibility of the suggestion strip in order to avoid clipped
                 // key previews, even when we don't show the suggestion strip.
+                mKeyPreviewBackingView.setVisibility(View.VISIBLE);
                 mSuggestionsContainer.setVisibility(
                         shouldShowSuggestions ? View.VISIBLE : View.INVISIBLE);
             }
@@ -967,15 +970,17 @@ public class LatinIME extends InputMethodServiceCompatWrapper implements Keyboar
         final KeyboardView inputView = mKeyboardSwitcher.getKeyboardView();
         if (inputView == null || mSuggestionsContainer == null)
             return;
-        final int containerHeight = mSuggestionsContainer.getHeight();
+        final int backingHeight = (mKeyPreviewBackingView.getVisibility() == View.GONE) ? 0
-        int touchY = containerHeight;
+                : mKeyPreviewBackingView.getHeight();
+        final int extraHeight = mSuggestionsContainer.getHeight() + backingHeight;
+        int touchY = extraHeight;
         // Need to set touchable region only if input view is being shown
         if (mKeyboardSwitcher.isInputViewShown()) {
             if (mSuggestionsContainer.getVisibility() == View.VISIBLE) {
                 touchY -= mSuggestionsStripHeight;
             }
             final int touchWidth = inputView.getWidth();
-            final int touchHeight = inputView.getHeight() + containerHeight
+            final int touchHeight = inputView.getHeight() + extraHeight
                     // Extend touchable region below the keyboard.
                     + EXTENDED_TOUCHABLE_REGION_HEIGHT;
             if (DEBUG) {