Remove nested preference from its parent.

PreferenceScreen.remvoePreference() only removes top level preference in
the preference screen. When we try to remove preference inside a
preference category, it will fail. Add handling to recursively find
the preference and remove it directly from its parent instead.

Change-Id: Ib33efe0b716db2366d712ce1d1eb8b5e33a4683a
Fix: 35365702
Test: make RunSettingsLibRoboTests

packages/SettingsLib/src/com/android/settingslib/core/AbstractPreferenceController.java

@@ -2,6 +2,7 @@ package com.android.settingslib.core;
 
 import android.content.Context;
 import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceGroup;
 import android.support.v7.preference.PreferenceScreen;
 import java.util.List;
 
@@ -73,9 +74,27 @@ public abstract class AbstractPreferenceController {
    * Removes preference from screen.
    */
   protected final void removePreference(PreferenceScreen screen, String key) {
-      Preference pref = screen.findPreference(key);
-      if (pref != null) {
-          screen.removePreference(pref);
-      }
+      findAndRemovePreference(screen, key);
   }
+
+  // finds the preference recursively and removes it from its parent
+  private boolean findAndRemovePreference(PreferenceGroup prefGroup, String key) {
+      final int preferenceCount = prefGroup.getPreferenceCount();
+      for (int i = 0; i < preferenceCount; i++) {
+          final Preference preference = prefGroup.getPreference(i);
+          final String curKey = preference.getKey();
+
+          if (curKey != null && curKey.equals(key)) {
+              return prefGroup.removePreference(preference);
+          }
+
+          if (preference instanceof PreferenceGroup) {
+              if (findAndRemovePreference((PreferenceGroup) preference, key)) {
+                  return true;
+              }
+          }
+      }
+      return false;
+  }
+
 }

packages/SettingsLib/tests/robotests/src/com/android/settingslib/core/PreferenceControllerTest.java

@@ -17,6 +17,8 @@ package com.android.settingslib.core;
 
 import android.content.Context;
 import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceGroup;
+import android.support.v7.preference.PreferenceManager;
 import android.support.v7.preference.PreferenceScreen;
 import com.android.settingslib.TestConfig;
 import com.android.settingslib.core.AbstractPreferenceController;
@@ -26,10 +28,13 @@ import org.junit.runner.RunWith;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
 import org.robolectric.annotation.Config;
+import org.robolectric.shadows.ShadowApplication;
 import org.robolectric.RobolectricTestRunner;
 
 import static org.mockito.Matchers.any;
+import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
@@ -54,7 +59,9 @@ public class PreferenceControllerTest {
 
     @Test
     public void removeExistingPref_shouldBeRemoved() {
-        when(mScreen.findPreference(TestPrefController.KEY_PREF)).thenReturn(mPreference);
+        when(mScreen.getPreferenceCount()).thenReturn(1);
+        when(mScreen.getPreference(0)).thenReturn(mPreference);
+        when(mPreference.getKey()).thenReturn(TestPrefController.KEY_PREF);
 
         mTestPrefController.removePreference(mScreen, TestPrefController.KEY_PREF);
 
@@ -79,7 +86,9 @@ public class PreferenceControllerTest {
 
     @Test
     public void doNotDisplayPref_ifNotAvailable() {
-        when(mScreen.findPreference(TestPrefController.KEY_PREF)).thenReturn(mPreference);
+        when(mScreen.getPreferenceCount()).thenReturn(1);
+        when(mScreen.getPreference(0)).thenReturn(mPreference);
+        when(mPreference.getKey()).thenReturn(TestPrefController.KEY_PREF);
         mTestPrefController.isAvailable = false;
 
         mTestPrefController.displayPreference(mScreen);
@@ -87,6 +96,61 @@ public class PreferenceControllerTest {
         verify(mScreen).removePreference(any(Preference.class));
     }
 
+    @Test
+    public void removePreference_shouldRemoveRecursively() {
+        final Context context = ShadowApplication.getInstance().getApplicationContext();
+        final PreferenceManager preferenceManager = mock(PreferenceManager.class);
+        // Top level
+        PreferenceScreen prefRoot = spy(new PreferenceScreen(context, null));
+        when(prefRoot.getPreferenceManager()).thenReturn(preferenceManager);
+        Preference pref1 = mock(Preference.class);
+        when(pref1.getKey()).thenReturn("key1");
+        PreferenceGroup prefGroup2 = spy(new PreferenceScreen(context, null));
+        when(prefGroup2.getPreferenceManager()).thenReturn(preferenceManager);
+        when(prefGroup2.getKey()).thenReturn("group2");
+        Preference pref3 = mock(Preference.class);
+        when(pref3.getKey()).thenReturn("key3");
+        PreferenceGroup prefGroup4 = spy(new PreferenceScreen(context, null));
+        when(prefGroup4.getPreferenceManager()).thenReturn(preferenceManager);
+        when(prefGroup4.getKey()).thenReturn("group4");
+        prefRoot.addPreference(pref1);
+        prefRoot.addPreference(prefGroup2);
+        prefRoot.addPreference(pref3);
+        prefRoot.addPreference(prefGroup4);
+
+        // 2nd level
+        Preference pref21 = mock(Preference.class);
+        when(pref21.getKey()).thenReturn("key21");
+        Preference pref22 = mock(Preference.class);
+        when(pref22.getKey()).thenReturn("key22");
+        prefGroup2.addPreference(pref21);
+        prefGroup2.addPreference(pref22);
+        PreferenceGroup prefGroup41 = spy(new PreferenceScreen(context, null));
+        when(prefGroup41.getKey()).thenReturn("group41");
+        when(prefGroup41.getPreferenceManager()).thenReturn(preferenceManager);
+        Preference pref42 = mock(Preference.class);
+        when(pref42.getKey()).thenReturn("key42");
+        prefGroup4.addPreference(prefGroup41);
+        prefGroup4.addPreference(pref42);
+
+        // 3rd level
+        Preference pref411 = mock(Preference.class);
+        when(pref411.getKey()).thenReturn("key411");
+        Preference pref412 = mock(Preference.class);
+        when(pref412.getKey()).thenReturn("key412");
+        prefGroup41.addPreference(pref411);
+        prefGroup41.addPreference(pref412);
+
+        mTestPrefController.removePreference(prefRoot, "key1");
+        verify(prefRoot).removePreference(pref1);
+
+        mTestPrefController.removePreference(prefRoot, "key411");
+        verify(prefGroup41).removePreference(pref411);
+
+        mTestPrefController.removePreference(prefRoot, "group41");
+        verify(prefGroup4).removePreference(prefGroup41);
+    }
+
     private class TestPrefController extends AbstractPreferenceController {
         private static final String KEY_PREF = "test_pref";
         public boolean isAvailable;