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      1 /*
      2  * Copyright (C) 2018 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.settings.core;
     18 
     19 import static com.android.settings.core.PreferenceXmlParserUtils.METADATA_CONTROLLER;
     20 import static com.android.settings.core.PreferenceXmlParserUtils.METADATA_KEY;
     21 
     22 import android.annotation.NonNull;
     23 import android.annotation.XmlRes;
     24 import android.content.Context;
     25 import android.os.Bundle;
     26 import android.text.TextUtils;
     27 import android.util.Log;
     28 
     29 import com.android.settings.core.PreferenceXmlParserUtils.MetadataFlag;
     30 import com.android.settingslib.core.AbstractPreferenceController;
     31 
     32 import org.xmlpull.v1.XmlPullParserException;
     33 
     34 import java.io.IOException;
     35 import java.util.ArrayList;
     36 import java.util.List;
     37 import java.util.Set;
     38 import java.util.TreeSet;
     39 
     40 /**
     41  * Helper to load {@link BasePreferenceController} lists from Xml.
     42  */
     43 public class PreferenceControllerListHelper {
     44 
     45     private static final String TAG = "PrefCtrlListHelper";
     46 
     47     /**
     48      * Instantiates a list of controller based on xml definition.
     49      */
     50     @NonNull
     51     public static List<BasePreferenceController> getPreferenceControllersFromXml(Context context,
     52             @XmlRes int xmlResId) {
     53         final List<BasePreferenceController> controllers = new ArrayList<>();
     54         List<Bundle> preferenceMetadata;
     55         try {
     56             preferenceMetadata = PreferenceXmlParserUtils.extractMetadata(context, xmlResId,
     57                     MetadataFlag.FLAG_NEED_KEY | MetadataFlag.FLAG_NEED_PREF_CONTROLLER);
     58         } catch (IOException | XmlPullParserException e) {
     59             Log.e(TAG, "Failed to parse preference xml for getting controllers", e);
     60             return controllers;
     61         }
     62 
     63         for (Bundle metadata : preferenceMetadata) {
     64             final String controllerName = metadata.getString(METADATA_CONTROLLER);
     65             if (TextUtils.isEmpty(controllerName)) {
     66                 continue;
     67             }
     68             BasePreferenceController controller;
     69             try {
     70                 controller = BasePreferenceController.createInstance(context, controllerName);
     71             } catch (IllegalStateException e) {
     72                 Log.d(TAG, "Could not find Context-only controller for pref: " + controllerName);
     73                 final String key = metadata.getString(METADATA_KEY);
     74                 if (TextUtils.isEmpty(key)) {
     75                     Log.w(TAG, "Controller requires key but it's not defined in xml: "
     76                             + controllerName);
     77                     continue;
     78                 }
     79                 try {
     80                     controller = BasePreferenceController.createInstance(context, controllerName,
     81                             key);
     82                 } catch (IllegalStateException e2) {
     83                     Log.w(TAG, "Cannot instantiate controller from reflection: " + controllerName);
     84                     continue;
     85                 }
     86             }
     87             controllers.add(controller);
     88         }
     89         return controllers;
     90     }
     91 
     92     /**
     93      * Return a sub list of {@link AbstractPreferenceController} to only contain controller that
     94      * doesn't exist in filter.
     95      *
     96      * @param filter The filter. This list will be unchanged.
     97      * @param input  This list will be filtered into a sublist and element is kept
     98      *               IFF the controller key is not used by anything from {@param filter}.
     99      */
    100     @NonNull
    101     public static List<BasePreferenceController> filterControllers(
    102             @NonNull List<BasePreferenceController> input,
    103             List<AbstractPreferenceController> filter) {
    104         if (input == null || filter == null) {
    105             return input;
    106         }
    107         final Set<String> keys = new TreeSet<>();
    108         final List<BasePreferenceController> filteredList = new ArrayList<>();
    109         for (AbstractPreferenceController controller : filter) {
    110             final String key = controller.getPreferenceKey();
    111             if (key != null) {
    112                 keys.add(key);
    113             }
    114         }
    115         for (BasePreferenceController controller : input) {
    116             if (keys.contains(controller.getPreferenceKey())) {
    117                 Log.w(TAG, controller.getPreferenceKey() + " already has a controller");
    118                 continue;
    119             }
    120             filteredList.add(controller);
    121         }
    122         return filteredList;
    123     }
    124 
    125 }
    126