1 /* 2 * Copyright (C) 2021 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 androidx.window.common; 18 19 import android.annotation.NonNull; 20 import android.annotation.Nullable; 21 import android.content.ContentResolver; 22 import android.content.Context; 23 import android.database.ContentObserver; 24 import android.net.Uri; 25 import android.os.Handler; 26 import android.os.Looper; 27 import android.provider.Settings; 28 import android.text.TextUtils; 29 import android.util.Log; 30 31 import androidx.window.util.BaseDataProducer; 32 33 import java.util.ArrayList; 34 import java.util.List; 35 import java.util.Optional; 36 37 /** 38 * Implementation of {@link androidx.window.util.DataProducer} that produces 39 * {@link CommonDisplayFeature} parsed from a string stored in {@link Settings}. 40 */ 41 public final class SettingsDisplayFeatureProducer 42 extends BaseDataProducer<List<DisplayFeature>> { 43 private static final boolean DEBUG = false; 44 private static final String TAG = "SettingsDisplayFeatureProducer"; 45 private static final String DISPLAY_FEATURES = "display_features"; 46 47 private final Uri mDisplayFeaturesUri = 48 Settings.Global.getUriFor(DISPLAY_FEATURES); 49 50 private final ContentResolver mResolver; 51 private final ContentObserver mObserver; 52 private boolean mRegisteredObservers; 53 SettingsDisplayFeatureProducer(@onNull Context context)54 public SettingsDisplayFeatureProducer(@NonNull Context context) { 55 mResolver = context.getContentResolver(); 56 mObserver = new SettingsObserver(); 57 } 58 59 @Override 60 @Nullable getData()61 public Optional<List<DisplayFeature>> getData() { 62 String displayFeaturesString = Settings.Global.getString(mResolver, DISPLAY_FEATURES); 63 if (displayFeaturesString == null) { 64 return Optional.empty(); 65 } 66 67 List<DisplayFeature> features = new ArrayList<>(); 68 if (TextUtils.isEmpty(displayFeaturesString)) { 69 return Optional.of(features); 70 } 71 String[] featureStrings = displayFeaturesString.split(";"); 72 73 for (String featureString : featureStrings) { 74 CommonDisplayFeature feature; 75 try { 76 feature = CommonDisplayFeature.parseFromString(featureString); 77 } catch (IllegalArgumentException e) { 78 if (DEBUG) { 79 Log.w(TAG, "Failed to parse display feature: " + featureString, e); 80 } 81 continue; 82 } 83 features.add(feature); 84 } 85 return Optional.of(features); 86 } 87 88 /** 89 * Registers settings observers, if needed. When settings observers are registered for this 90 * producer callbacks for changes in data will be triggered. 91 */ registerObserversIfNeeded()92 public void registerObserversIfNeeded() { 93 if (mRegisteredObservers) { 94 return; 95 } 96 mRegisteredObservers = true; 97 mResolver.registerContentObserver(mDisplayFeaturesUri, false /* notifyForDescendants */, 98 mObserver /* ContentObserver */); 99 } 100 101 /** 102 * Unregisters settings observers, if needed. When settings observers are unregistered for this 103 * producer callbacks for changes in data will not be triggered. 104 */ unregisterObserversIfNeeded()105 public void unregisterObserversIfNeeded() { 106 if (!mRegisteredObservers) { 107 return; 108 } 109 mRegisteredObservers = false; 110 mResolver.unregisterContentObserver(mObserver); 111 } 112 113 private final class SettingsObserver extends ContentObserver { SettingsObserver()114 SettingsObserver() { 115 super(new Handler(Looper.getMainLooper())); 116 } 117 118 @Override onChange(boolean selfChange, Uri uri)119 public void onChange(boolean selfChange, Uri uri) { 120 if (mDisplayFeaturesUri.equals(uri)) { 121 notifyDataChanged(); 122 } 123 } 124 } 125 } 126