Recursively remove preference from screen.

The preference framework does not remove pref recursively. So when a
preference is nested in preference hierarchy, it's not safe to simply
call screen.removePreference(). We need to first find its parent and
remove pref from its parent.

Change-Id: Ic7fefa498ed71a8877d862845ddcc2d6d6034a55
Fix: 38507066
Test: make RunSettingsRoboTests

src/com/android/settings/SettingsPreferenceFragment.java

@@ -26,6 +26,7 @@ import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.os.Bundle;
+import android.support.annotation.VisibleForTesting;
 import android.support.annotation.XmlRes;
 import android.support.v7.preference.Preference;
 import android.support.v7.preference.PreferenceGroup;
@@ -423,11 +424,28 @@ public abstract class SettingsPreferenceFragment extends InstrumentedPreferenceF
         return -1;
     }
 
-    protected void removePreference(String key) {
+    protected boolean removePreference(String key) {
-        Preference pref = findPreference(key);
+        return removePreference(getPreferenceScreen(), key);
-        if (pref != null) {
+    }
-            getPreferenceScreen().removePreference(pref);
+
+    @VisibleForTesting
+    boolean removePreference(PreferenceGroup group, String key) {
+        final int preferenceCount = group.getPreferenceCount();
+        for (int i = 0; i < preferenceCount; i++) {
+            final Preference preference = group.getPreference(i);
+            final String curKey = preference.getKey();
+
+            if (TextUtils.equals(curKey, key)) {
+                return group.removePreference(preference);
+            }
+
+            if (preference instanceof PreferenceGroup) {
+                if (removePreference((PreferenceGroup) preference, key)) {
+                    return true;
+                }
+            }
         }
+        return false;
     }
 
     /**

tests/robotests/src/com/android/settings/SettingsPreferenceFragmentTest.java

@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2017 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.settings;
+
+
+import android.content.Context;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceCategory;
+import android.support.v7.preference.PreferenceManager;
+import android.support.v7.preference.PreferenceScreen;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RuntimeEnvironment;
+import org.robolectric.annotation.Config;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
+
+@RunWith(SettingsRobolectricTestRunner.class)
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+public class SettingsPreferenceFragmentTest {
+
+    @Mock
+    private PreferenceManager mPreferenceManager;
+    private Context mContext;
+    private TestFragment mFragment;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        mContext = RuntimeEnvironment.application;
+        mFragment = new TestFragment();
+    }
+
+    @Test
+    public void removePreference_nested_shouldRemove() {
+        final String key = "test_key";
+        final PreferenceScreen mScreen = spy(new PreferenceScreen(mContext, null));
+        when(mScreen.getPreferenceManager()).thenReturn(mock(PreferenceManager.class));
+
+        final PreferenceCategory nestedCategory = new ProgressCategory(mContext);
+        final Preference preference = new Preference(mContext);
+        preference.setKey(key);
+        preference.setPersistent(false);
+
+        mScreen.addPreference(nestedCategory);
+        nestedCategory.addPreference(preference);
+
+        assertThat(mFragment.removePreference(mScreen, key)).isTrue();
+        assertThat(nestedCategory.getPreferenceCount()).isEqualTo(0);
+    }
+
+    @Test
+    public void removePreference_flat_shouldRemove() {
+        final String key = "test_key";
+        final PreferenceScreen mScreen = spy(new PreferenceScreen(mContext, null));
+        when(mScreen.getPreferenceManager()).thenReturn(mock(PreferenceManager.class));
+
+        final Preference preference = mock(Preference.class);
+        when(preference.getKey()).thenReturn(key);
+
+        mScreen.addPreference(preference);
+
+        assertThat(mFragment.removePreference(mScreen, key)).isTrue();
+        assertThat(mScreen.getPreferenceCount()).isEqualTo(0);
+    }
+
+    @Test
+    public void removePreference_doNotExist_shouldNotRemove() {
+        final String key = "test_key";
+        final PreferenceScreen mScreen = spy(new PreferenceScreen(mContext, null));
+        when(mScreen.getPreferenceManager()).thenReturn(mock(PreferenceManager.class));
+
+        final Preference preference = mock(Preference.class);
+        when(preference.getKey()).thenReturn(key);
+
+        mScreen.addPreference(preference);
+
+        assertThat(mFragment.removePreference(mScreen, "not" + key)).isFalse();
+        assertThat(mScreen.getPreferenceCount()).isEqualTo(1);
+    }
+
+    public static final class TestFragment extends SettingsPreferenceFragment {
+
+        @Override
+        public int getMetricsCategory() {
+            return 0;
+        }
+    }
+
+
+}