| /* |
| * Copyright (C) 2016 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.storagemanager.utils; |
| |
| import androidx.preference.Preference; |
| import androidx.preference.PreferenceGroup; |
| import android.text.TextUtils; |
| import android.util.ArrayMap; |
| |
| /** |
| * The PreferenceListCache is a cache of preferences sourced from a {@link PreferenceGroup} which |
| * allows for the re-use of the same preference object when re-creating a list of preferences. |
| */ |
| public class PreferenceListCache { |
| private PreferenceGroup mGroup; |
| private ArrayMap<String, Preference> mCache; |
| |
| /** |
| * Constructs a PreferenceListCache using the preferences within the given PreferenceGroup. |
| * @param group The preference group to source preferences from. |
| */ |
| public PreferenceListCache(PreferenceGroup group) { |
| mGroup = group; |
| mCache = new ArrayMap<>(); |
| final int N = group.getPreferenceCount(); |
| for (int i = 0; i < N; i++) { |
| Preference p = group.getPreference(i); |
| String key = p.getKey(); |
| if (TextUtils.isEmpty(key) || mCache.containsKey(key)) { |
| throw new IllegalArgumentException( |
| "Invalid key encountered in preference group " + group.getKey()); |
| } |
| mCache.put(p.getKey(), p); |
| } |
| } |
| |
| /** |
| * Removes a cached preferenced from the cache, if it exists. |
| * @param key The key of the preference. |
| * @return The preference, if it exists in the cache, or null. |
| */ |
| public Preference getCachedPreference(String key) { |
| return mCache.remove(key); |
| } |
| |
| /** |
| * Removes the un-reused preferences from the original PreferenceGroup. |
| */ |
| public void removeCachedPrefs() { |
| for (Preference p : mCache.values()) { |
| mGroup.removePreference(p); |
| } |
| } |
| } |