Make CandidateView backward compatible

Up to version 10 (Gingerbread) of the API, FrameLayout doesn't handle
margin properly.  This change inserts RelativeLayout to FrameLayout as
placer to set margin and place children views absolutely.

Change-Id: Iee785bc2da77677738caf456bcd2bbf57b89f007

3 files changed, 70 insertions, 35 deletions

diff --git a/java/src/com/android/inputmethod/compat/FrameLayoutCompatUtils.java b/java/src/com/android/inputmethod/compat/FrameLayoutCompatUtils.java
new file mode 100644
index 000000000..46499f19a
--- /dev/null
+++ b/java/src/com/android/inputmethod/compat/FrameLayoutCompatUtils.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2011 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.
+ */
+
+package com.android.inputmethod.compat;
+
+import android.view.ViewGroup;
+import android.view.ViewGroup.MarginLayoutParams;
+import android.widget.FrameLayout;
+import android.widget.RelativeLayout;
+
+public class FrameLayoutCompatUtils {
+    private static final boolean NEEDS_FRAME_LAYOUT_HACK = (
+            android.os.Build.VERSION.SDK_INT < 11 /* Honeycomb */);
+
+    public static ViewGroup getPlacer(ViewGroup container) {
+        if (NEEDS_FRAME_LAYOUT_HACK) {
+            // Insert RelativeLayout to be able to setMargin because pre-Honeycomb FrameLayout
+            // could not handle setMargin properly.
+            final ViewGroup placer = new RelativeLayout(container.getContext());
+            container.addView(placer);
+            return placer;
+        } else {
+            return container;
+        }
+    }
+
+    public static MarginLayoutParams newLayoutParam(ViewGroup placer, int width, int height) {
+        if (placer instanceof FrameLayout) {
+            return new FrameLayout.LayoutParams(width, height);
+        } else if (placer instanceof RelativeLayout) {
+            return new RelativeLayout.LayoutParams(width, height);
+        } else if (placer == null) {
+            throw new NullPointerException("placer is null");
+        } else {
+            throw new IllegalArgumentException("placer is neither FrameLayout nor RelativeLayout: "
+                    + placer.getClass().getName());
+        }
+    }
+}
diff --git a/java/src/com/android/inputmethod/keyboard/KeyboardView.java b/java/src/com/android/inputmethod/keyboard/KeyboardView.java
index 4c6f29a92..c372281c2 100644
--- a/java/src/com/android/inputmethod/keyboard/KeyboardView.java
+++ b/java/src/com/android/inputmethod/keyboard/KeyboardView.java
@@ -42,11 +42,10 @@ import android.view.View;
 import android.view.ViewConfiguration;
 import android.view.ViewGroup;
 import android.view.ViewGroup.MarginLayoutParams;
-import android.widget.FrameLayout;
-import android.widget.LinearLayout;
 import android.widget.PopupWindow;
 import android.widget.TextView;
 
+import com.android.inputmethod.compat.FrameLayoutCompatUtils;
 import com.android.inputmethod.keyboard.internal.Key;
 import com.android.inputmethod.keyboard.internal.MiniKeyboardBuilder;
 import com.android.inputmethod.keyboard.internal.PointerTrackerQueue;
@@ -946,27 +945,12 @@ public class KeyboardView extends View implements PointerTracker.UIProxy {
     }
 
     private void addKeyPreview(TextView keyPreview) {
-        ViewGroup placer = mPreviewPlacer;
-        if (placer == null) {
-            final FrameLayout screenContent = (FrameLayout) getRootView().findViewById(
-                    android.R.id.content);
-            if (android.os.Build.VERSION.SDK_INT >= /* HONEYCOMB */11) {
-                placer = screenContent;
-            } else {
-                // Insert LinearLayout to be able to setMargin because pre-Honeycomb FrameLayout
-                // could not handle setMargin properly.
-                placer = new LinearLayout(getContext());
-                screenContent.addView(placer);
-            }
-            mPreviewPlacer = placer;
-        }
-        if (placer instanceof FrameLayout) {
-            // Honeycomb or later.
-            placer.addView(keyPreview, new FrameLayout.LayoutParams(0, 0));
-        } else {
-            // Gingerbread or ealier.
-            placer.addView(keyPreview, new LinearLayout.LayoutParams(0, 0));
+        if (mPreviewPlacer == null) {
+            mPreviewPlacer = FrameLayoutCompatUtils.getPlacer(
+                    (ViewGroup)getRootView().findViewById(android.R.id.content));
         }
+        final ViewGroup placer = mPreviewPlacer;
+        placer.addView(keyPreview, FrameLayoutCompatUtils.newLayoutParam(placer, 0, 0));
     }
 
     // TODO: Introduce minimum duration for displaying key previews
diff --git a/java/src/com/android/inputmethod/latin/CandidateView.java b/java/src/com/android/inputmethod/latin/CandidateView.java
index fa27ca5ad..09b356d65 100644
--- a/java/src/com/android/inputmethod/latin/CandidateView.java
+++ b/java/src/com/android/inputmethod/latin/CandidateView.java
@@ -44,6 +44,7 @@ import android.widget.LinearLayout;
 import android.widget.PopupWindow;
 import android.widget.TextView;
 
+import com.android.inputmethod.compat.FrameLayoutCompatUtils;
 import com.android.inputmethod.compat.LinearLayoutCompatUtils;
 import com.android.inputmethod.latin.SuggestedWords.SuggestedWordInfo;
 
@@ -244,7 +245,8 @@ public class CandidateView extends LinearLayout implements OnClickListener, OnLo
     public void setListener(Listener listener, View inputView) {
         mListener = listener;
         mKeyboardView = inputView.findViewById(R.id.keyboard_view);
-        mCandidatesPane = (ViewGroup)inputView.findViewById(R.id.candidates_pane);
+        mCandidatesPane = FrameLayoutCompatUtils.getPlacer(
+                (ViewGroup)inputView.findViewById(R.id.candidates_pane));
         mCandidatesPane.setOnClickListener(this);
         mCandidatesPaneContainer = (ViewGroup)inputView.findViewById(
                 R.id.candidates_pane_container);
@@ -346,12 +348,10 @@ public class CandidateView extends LinearLayout implements OnClickListener, OnLo
                 }
                 if (x != 0) {
                     final View divider = mDividers.get(i - NUM_CANDIDATES_IN_STRIP);
-                    mCandidatesPane.addView(divider);
-                    placeCandidateAt(divider, x, y);
+                    addCandidateAt(divider, x, y);
                     x += dividerWidth;
                 }
-                mCandidatesPane.addView(tv);
-                placeCandidateAt(tv, x, y);
+                addCandidateAt(tv, x, y);
                 x += width;
             }
 
@@ -372,14 +372,13 @@ public class CandidateView extends LinearLayout implements OnClickListener, OnLo
         }
     }
 
-    private void placeCandidateAt(View v, int x, int y) {
-        ViewGroup.LayoutParams lp = v.getLayoutParams();
-        if (lp instanceof ViewGroup.MarginLayoutParams) {
-            ViewGroup.MarginLayoutParams mlp = (ViewGroup.MarginLayoutParams)lp;
-            mlp.width = v.getMeasuredWidth();
-            mlp.height = v.getMeasuredHeight();
-            mlp.setMargins(x, y + (mCandidateStripHeight - mlp.height) / 2, 0, 0);
-        }
+    private void addCandidateAt(View v, int x, int y) {
+        final int width = v.getMeasuredWidth();
+        final int height = v.getMeasuredHeight();
+        final MarginLayoutParams marginLayoutParams = FrameLayoutCompatUtils.newLayoutParam(
+                mCandidatesPane, width, height);
+        marginLayoutParams.setMargins(x, y + (mCandidateStripHeight - height) / 2, 0, 0);
+        mCandidatesPane.addView(v, marginLayoutParams);
     }
 
     private void centeringCandidates(int from, int to, int width, int paneWidth) {