[PB8] Add an animation upon status change.

Bug: 7600384
Change-Id: If5efb9357075193d10255187008e870e2933bdb8

java/src/com/android/inputmethod/dictionarypack/ButtonSwitcher.java

@@ -16,9 +16,12 @@
 
 package com.android.inputmethod.dictionarypack;
 
+import android.animation.Animator;
+import android.animation.AnimatorListenerAdapter;
 import android.content.Context;
 import android.util.AttributeSet;
 import android.view.View;
+import android.view.ViewPropertyAnimator;
 import android.widget.Button;
 import android.widget.FrameLayout;
 
@@ -115,22 +118,35 @@ public class ButtonSwitcher extends FrameLayout {
     }
 
     private void animateButtonPosition(final int oldStatus, final int newStatus) {
-        animateButton(getButton(oldStatus), ANIMATION_OUT);
-        animateButton(getButton(newStatus), ANIMATION_IN);
+        final View oldButton = getButton(oldStatus);
+        final View newButton = getButton(newStatus);
+        if (null != oldButton && null != newButton) {
+            // Transition between two buttons : animate out, then in
+            animateButton(oldButton, ANIMATION_OUT).setListener(
+                    new AnimatorListenerAdapter() {
+                        @Override
+                        public void onAnimationEnd(final Animator animation) {
+                            animateButton(newButton, ANIMATION_IN);
+                        }
+                    });
+        } else if (null != oldButton) {
+            animateButton(oldButton, ANIMATION_OUT);
+        } else if (null != newButton) {
+            animateButton(newButton, ANIMATION_IN);
+        }
     }
 
     public void setInternalOnClickListener(final OnClickListener listener) {
         mOnClickListener = listener;
     }
 
-    private void animateButton(final View button, final int direction) {
-        if (null == button) return;
+    private ViewPropertyAnimator animateButton(final View button, final int direction) {
         final float outerX = getWidth();
         final float innerX = button.getX() - button.getTranslationX();
         if (ANIMATION_IN == direction) {
-            button.animate().translationX(0);
+            return button.animate().translationX(0);
         } else {
-            button.animate().translationX(outerX - innerX);
+            return button.animate().translationX(outerX - innerX);
         }
     }
 }

java/src/com/android/inputmethod/dictionarypack/DictionaryListInterfaceState.java

@@ -44,6 +44,12 @@ public class DictionaryListInterfaceState {
         return state.mOpen;
     }
 
+    public int getStatus(final String wordlistId) {
+        final State state = mWordlistToState.get(wordlistId);
+        if (null == state) return MetadataDbHelper.STATUS_UNKNOWN;
+        return state.mStatus;
+    }
+
     public void setOpen(final String wordlistId, final int status) {
         final State newState;
         final State state = mWordlistToState.get(wordlistId);

java/src/com/android/inputmethod/dictionarypack/WordListPreference.java

@@ -191,8 +191,20 @@ public final class WordListPreference extends Preference {
         ((ViewGroup)view).setLayoutTransition(null);
         final ButtonSwitcher buttonSwitcher =
                 (ButtonSwitcher)view.findViewById(R.id.wordlist_button_switcher);
-        buttonSwitcher.setStatusAndUpdateVisuals(mInterfaceState.isOpen(mWordlistId) ?
-                getButtonSwitcherStatus(mStatus) : ButtonSwitcher.STATUS_NO_BUTTON);
+        if (mInterfaceState.isOpen(mWordlistId)) {
+            // The button is open.
+            final int previousStatus = mInterfaceState.getStatus(mWordlistId);
+            buttonSwitcher.setStatusAndUpdateVisuals(getButtonSwitcherStatus(previousStatus));
+            if (previousStatus != mStatus) {
+                // We come here if the status has changed since last time. We need to animate
+                // the transition.
+                buttonSwitcher.setStatusAndUpdateVisuals(getButtonSwitcherStatus(mStatus));
+                mInterfaceState.setOpen(mWordlistId, mStatus);
+            }
+        } else {
+            // The button is closed.
+            buttonSwitcher.setStatusAndUpdateVisuals(ButtonSwitcher.STATUS_NO_BUTTON);
+        }
         buttonSwitcher.setInternalOnClickListener(mActionButtonClickHandler);
         view.setOnClickListener(mPreferenceClickHandler);
     }