Enable recycling of third party preference widgets

Until now we have been recycling only framework preference widgets since
there were no guarantees for third party preferences to support recycling.
This let to broken animations for preference widgets that are outside of
the framework.

This change makes recycling to be used always and in case the developers
need to turn it off they can explicitely use a new attribute that is
being added to the Preference called "recycleEnabled" and set it to false.

Bug: b/34334451
Test: Test are part of the same topic.

Change-Id: I324087841e1edddbf0d3eaad00b5895a196acff6

2 files changed, 82 insertions, 64 deletions

diff --git a/core/java/android/preference/Preference.java b/core/java/android/preference/Preference.java
index 443a3e968b9c..d5de660ad0e7 100644
--- a/core/java/android/preference/Preference.java
+++ b/core/java/android/preference/Preference.java
@@ -81,6 +81,7 @@ import java.util.Set;
  * @attr ref android.R.styleable#Preference_persistent
  * @attr ref android.R.styleable#Preference_defaultValue
  * @attr ref android.R.styleable#Preference_shouldDisableView
+ * @attr ref android.R.styleable#Preference_recycleEnabled
  */
 public class Preference implements Comparable<Preference> {
     /**
@@ -131,6 +132,7 @@ public class Preference implements Comparable<Preference> {
     private Object mDefaultValue;
     private boolean mDependencyMet = true;
     private boolean mParentDependencyMet = true;
+    private boolean mRecycleEnabled = true;
 
     /**
      * @see #setShouldDisableView(boolean)
@@ -139,7 +141,6 @@ public class Preference implements Comparable<Preference> {
 
     private int mLayoutResId = com.android.internal.R.layout.preference;
     private int mWidgetLayoutResId;
-    private boolean mCanRecycleLayout = true;
 
     private OnPreferenceChangeInternalListener mListener;
 
@@ -291,15 +292,13 @@ public class Preference implements Comparable<Preference> {
                 case com.android.internal.R.styleable.Preference_shouldDisableView:
                     mShouldDisableView = a.getBoolean(attr, mShouldDisableView);
                     break;
+
+                case com.android.internal.R.styleable.Preference_recycleEnabled:
+                    mRecycleEnabled = a.getBoolean(attr, mRecycleEnabled);
+                    break;
             }
         }
         a.recycle();
-
-        if (!getClass().getName().startsWith("android.preference")
-                && !getClass().getName().startsWith("com.android")) {
-            // For non-framework subclasses, assume the worst and don't cache views.
-            mCanRecycleLayout = false;
-        }
     }
 
     /**
@@ -482,7 +481,7 @@ public class Preference implements Comparable<Preference> {
     public void setLayoutResource(@LayoutRes int layoutResId) {
         if (layoutResId != mLayoutResId) {
             // Layout changed
-            mCanRecycleLayout = false;
+            mRecycleEnabled = false;
         }
 
         mLayoutResId = layoutResId;
@@ -511,7 +510,7 @@ public class Preference implements Comparable<Preference> {
     public void setWidgetLayoutResource(@LayoutRes int widgetLayoutResId) {
         if (widgetLayoutResId != mWidgetLayoutResId) {
             // Layout changed
-            mCanRecycleLayout = false;
+            mRecycleEnabled = false;
         }
         mWidgetLayoutResId = widgetLayoutResId;
     }
@@ -653,15 +652,13 @@ public class Preference implements Comparable<Preference> {
     }
 
     /**
-     * Sets the order of this Preference with respect to other
-     * Preference objects on the same level. If this is not specified, the
-     * default behavior is to sort alphabetically. The
-     * {@link PreferenceGroup#setOrderingAsAdded(boolean)} can be used to order
-     * Preference objects based on the order they appear in the XML.
+     * Sets the order of this Preference with respect to other Preference objects on the same level.
+     * If this is not specified, the default behavior is to sort alphabetically. The
+     * {@link PreferenceGroup#setOrderingAsAdded(boolean)} can be used to order Preference objects
+     * based on the order they appear in the XML.
      *
-     * @param order The order for this Preference. A lower value will be shown
-     *            first. Use {@link #DEFAULT_ORDER} to sort alphabetically or
-     *            allow ordering from XML.
+     * @param order the order for this Preference. A lower value will be shown first. Use
+     *              {@link #DEFAULT_ORDER} to sort alphabetically or allow ordering from XML
      * @see PreferenceGroup#setOrderingAsAdded(boolean)
      * @see #DEFAULT_ORDER
      */
@@ -669,16 +666,15 @@ public class Preference implements Comparable<Preference> {
         if (order != mOrder) {
             mOrder = order;
 
-            // Reorder the list 
+            // Reorder the list
             notifyHierarchyChanged();
         }
     }
 
     /**
-     * Gets the order of this Preference with respect to other Preference objects
-     * on the same level.
+     * Gets the order of this Preference with respect to other Preference objects on the same level.
      *
-     * @return The order of this Preference.
+     * @return the order of this Preference
      * @see #setOrder(int)
      */
     public int getOrder() {
@@ -686,12 +682,10 @@ public class Preference implements Comparable<Preference> {
     }
 
     /**
-     * Sets the title for this Preference with a CharSequence. 
-     * This title will be placed into the ID
-     * {@link android.R.id#title} within the View created by
-     * {@link #onCreateView(ViewGroup)}.
+     * Sets the title for this Preference with a CharSequence. This title will be placed into the ID
+     * {@link android.R.id#title} within the View created by {@link #onCreateView(ViewGroup)}.
      *
-     * @param title The title for this Preference.
+     * @param title the title for this Preference
      */
     public void setTitle(CharSequence title) {
         if (title == null && mTitle != null || title != null && !title.equals(mTitle)) {
@@ -702,10 +696,10 @@ public class Preference implements Comparable<Preference> {
     }
 
     /**
-     * Sets the title for this Preference with a resource ID. 
+     * Sets the title for this Preference with a resource ID.
      *
      * @see #setTitle(CharSequence)
-     * @param titleResId The title as a resource ID.
+     * @param titleResId the title as a resource ID
      */
     public void setTitle(@StringRes int titleResId) {
         setTitle(mContext.getString(titleResId));
@@ -713,10 +707,10 @@ public class Preference implements Comparable<Preference> {
     }
 
     /**
-     * Returns the title resource ID of this Preference.  If the title did
-     * not come from a resource, 0 is returned.
+     * Returns the title resource ID of this Preference. If the title did not come from a resource,
+     * {@code 0} is returned.
      *
-     * @return The title resource.
+     * @return the title resource
      * @see #setTitle(int)
      */
     @StringRes
@@ -727,7 +721,7 @@ public class Preference implements Comparable<Preference> {
     /**
      * Returns the title of this Preference.
      *
-     * @return The title.
+     * @return the title
      * @see #setTitle(CharSequence)
      */
     public CharSequence getTitle() {
@@ -735,12 +729,10 @@ public class Preference implements Comparable<Preference> {
     }
 
     /**
-     * Sets the icon for this Preference with a Drawable. 
-     * This icon will be placed into the ID
-     * {@link android.R.id#icon} within the View created by
-     * {@link #onCreateView(ViewGroup)}.
+     * Sets the icon for this Preference with a Drawable. This icon will be placed into the ID
+     * {@link android.R.id#icon} within the View created by {@link #onCreateView(ViewGroup)}.
      *
-     * @param icon The optional icon for this Preference.
+     * @param icon the optional icon for this Preference
      */
     public void setIcon(Drawable icon) {
         if ((icon == null && mIcon != null) || (icon != null && mIcon != icon)) {
@@ -751,10 +743,10 @@ public class Preference implements Comparable<Preference> {
     }
 
     /**
-     * Sets the icon for this Preference with a resource ID. 
+     * Sets the icon for this Preference with a resource ID.
      *
      * @see #setIcon(Drawable)
-     * @param iconResId The icon as a resource ID.
+     * @param iconResId the icon as a resource ID
      */
     public void setIcon(@DrawableRes int iconResId) {
         if (mIconResId != iconResId) {
@@ -766,7 +758,7 @@ public class Preference implements Comparable<Preference> {
     /**
      * Returns the icon of this Preference.
      *
-     * @return The icon.
+     * @return the icon
      * @see #setIcon(Drawable)
      */
     public Drawable getIcon() {
@@ -779,7 +771,7 @@ public class Preference implements Comparable<Preference> {
     /**
      * Returns the summary of this Preference.
      *
-     * @return The summary.
+     * @return the summary
      * @see #setSummary(CharSequence)
      */
     public CharSequence getSummary() {
@@ -787,9 +779,9 @@ public class Preference implements Comparable<Preference> {
     }
 
     /**
-     * Sets the summary for this Preference with a CharSequence. 
+     * Sets the summary for this Preference with a CharSequence.
      *
-     * @param summary The summary for the preference.
+     * @param summary the summary for the preference
      */
     public void setSummary(CharSequence summary) {
         if (summary == null && mSummary != null || summary != null && !summary.equals(mSummary)) {
@@ -799,10 +791,10 @@ public class Preference implements Comparable<Preference> {
     }
 
     /**
-     * Sets the summary for this Preference with a resource ID. 
+     * Sets the summary for this Preference with a resource ID.
      *
      * @see #setSummary(CharSequence)
-     * @param summaryResId The summary as a resource.
+     * @param summaryResId the summary as a resource
      */
     public void setSummary(@StringRes int summaryResId) {
         setSummary(mContext.getString(summaryResId));
@@ -812,7 +804,7 @@ public class Preference implements Comparable<Preference> {
      * Sets whether this Preference is enabled. If disabled, it will
      * not handle clicks.
      *
-     * @param enabled Set true to enable it.
+     * @param enabled set {@code true} to enable it
      */
     public void setEnabled(boolean enabled) {
         if (mEnabled != enabled) {
@@ -828,7 +820,7 @@ public class Preference implements Comparable<Preference> {
     /**
      * Checks whether this Preference should be enabled in the list.
      *
-     * @return True if this Preference is enabled, false otherwise.
+     * @return {@code true} if this Preference is enabled, false otherwise
      */
     public boolean isEnabled() {
         return mEnabled && mDependencyMet && mParentDependencyMet;
@@ -837,7 +829,7 @@ public class Preference implements Comparable<Preference> {
     /**
      * Sets whether this Preference is selectable.
      *
-     * @param selectable Set true to make it selectable.
+     * @param selectable set {@code true} to make it selectable
      */
     public void setSelectable(boolean selectable) {
         if (mSelectable != selectable) {
@@ -849,22 +841,21 @@ public class Preference implements Comparable<Preference> {
     /**
      * Checks whether this Preference should be selectable in the list.
      *
-     * @return True if it is selectable, false otherwise.
+     * @return {@code true} if it is selectable, {@code false} otherwise
      */
     public boolean isSelectable() {
         return mSelectable;
     }
 
     /**
-     * Sets whether this Preference should disable its view when it gets
-     * disabled.
-     * <p>
-     * For example, set this and {@link #setEnabled(boolean)} to false for
-     * preferences that are only displaying information and 1) should not be
-     * clickable 2) should not have the view set to the disabled state.
+     * Sets whether this Preference should disable its view when it gets disabled.
      *
-     * @param shouldDisableView Set true if this preference should disable its view
-     *            when the preference is disabled.
+     * <p>For example, set this and {@link #setEnabled(boolean)} to false for preferences that are
+     * only displaying information and 1) should not be clickable 2) should not have the view set to
+     * the disabled state.
+     *
+     * @param shouldDisableView set {@code true} if this preference should disable its view when
+     *                          the preference is disabled
      */
     public void setShouldDisableView(boolean shouldDisableView) {
         mShouldDisableView = shouldDisableView;
@@ -873,14 +864,45 @@ public class Preference implements Comparable<Preference> {
 
     /**
      * Checks whether this Preference should disable its view when it's action is disabled.
+     *
      * @see #setShouldDisableView(boolean)
-     * @return True if it should disable the view. 
+     * @return {@code true} if it should disable the view
      */
     public boolean getShouldDisableView() {
         return mShouldDisableView;
     }
 
     /**
+     * Sets whether this Preference has enabled to have its view recycled when used in the list
+     * view. By default the recycling is enabled.
+     *
+     * <p>The value can be changed only before this preference is added to the preference hierarchy.
+     *
+     * <p>If view recycling is not allowed then each time the list view populates this preference
+     * the {@link #getView(View, ViewGroup)} method receives a {@code null} convert view and needs
+     * to recreate the view. Otherwise view gets recycled and only {@link #onBindView(View)} gets
+     * called.
+     *
+     * @param enabled set {@code true} if this preference view should be recycled
+     */
+    @CallSuper
+    public void setRecycleEnabled(boolean enabled) {
+        mRecycleEnabled = enabled;
+        notifyChanged();
+    }
+
+    /**
+     * Checks whether this Preference has enabled to have its view recycled when used in the list
+     * view.
+     *
+     * @see #setRecycleEnabled(boolean)
+     * @return {@code true} if this preference view should be recycled
+     */
+    public boolean isRecycleEnabled() {
+        return mRecycleEnabled;
+    }
+
+    /**
      * Returns a unique ID for this Preference.  This ID should be unique across all
      * Preference objects in a hierarchy.
      *
@@ -1831,10 +1853,6 @@ public class Preference implements Comparable<Preference> {
         return mPreferenceManager.getSharedPreferences().getBoolean(mKey, defaultReturnValue);
     }
 
-    boolean canRecycleLayout() {
-        return mCanRecycleLayout;
-    }
-
     @Override
     public String toString() {
         return getFilterableStringBuilder().toString();
diff --git a/core/java/android/preference/PreferenceGroupAdapter.java b/core/java/android/preference/PreferenceGroupAdapter.java
index 5a0b9e953c16..bee45ab0fe32 100644
--- a/core/java/android/preference/PreferenceGroupAdapter.java
+++ b/core/java/android/preference/PreferenceGroupAdapter.java
@@ -164,7 +164,7 @@ public class PreferenceGroupAdapter extends BaseAdapter
             
             preferences.add(preference);
             
-            if (!mHasReturnedViewTypeCount && preference.canRecycleLayout()) {
+            if (!mHasReturnedViewTypeCount && preference.isRecycleEnabled()) {
                 addPreferenceClassName(preference);
             }
             
@@ -296,7 +296,7 @@ public class PreferenceGroupAdapter extends BaseAdapter
         }
         
         final Preference preference = this.getItem(position);
-        if (!preference.canRecycleLayout()) {
+        if (!preference.isRecycleEnabled()) {
             return IGNORE_ITEM_VIEW_TYPE;
         }