Add getParent() on Preference.

Preference class now keeps track of its PreferenceGroup parent which
makes it easier to remove it from the preference hierarchy.

This required a new API method.

Test: Separate CTS CL being submitted along this one, see the topic.
BUG: 30599046
Change-Id: Ia9f274ef0315cb09a8c558e781b10f57efd28406

1 files changed, 23 insertions, 0 deletions

diff --git a/core/java/android/preference/Preference.java b/core/java/android/preference/Preference.java
index 8303bca34bee..089eaeceac55 100644
--- a/core/java/android/preference/Preference.java
+++ b/core/java/android/preference/Preference.java
@@ -145,6 +145,8 @@ public class Preference implements Comparable<Preference> {
 
     private List<Preference> mDependents;
 
+    private PreferenceGroup mParentGroup;
+
     private boolean mBaseMethodCalled;
 
     /**
@@ -1238,6 +1240,16 @@ public class Preference implements Comparable<Preference> {
         registerDependency();
     }
 
+    /**
+     * Assigns a {@link PreferenceGroup} as the parent of this Preference. Set null to remove
+     * the current parent.
+     *
+     * @param parentGroup Parent preference group of this Preference or null if none.
+     */
+    void assignParent(@Nullable PreferenceGroup parentGroup) {
+        mParentGroup = parentGroup;
+    }
+
     private void registerDependency() {
 
         if (TextUtils.isEmpty(mDependencyKey)) return;
@@ -1401,6 +1413,17 @@ public class Preference implements Comparable<Preference> {
     }
 
     /**
+     * Returns the {@link PreferenceGroup} which is this Preference assigned to or null if this
+     * preference is not assigned to any group or is a root Preference.
+     *
+     * @return The parent PreferenceGroup or null if not attached to any.
+     */
+    @Nullable
+    public PreferenceGroup getParent() {
+        return mParentGroup;
+    }
+
+    /**
      * Called when this Preference is being removed from the hierarchy. You
      * should remove any references to this Preference that you know about. Make
      * sure to call through to the superclass implementation.