src/com/android/emergency/preferences/EmergencyContactsPreference.java

/*
 * 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.emergency.preferences;

import android.content.Context;
import android.net.Uri;
import android.preference.Preference;
import android.preference.PreferenceCategory;
import android.util.ArraySet;
import android.util.AttributeSet;

import com.android.emergency.EmergencyContactManager;
import com.android.emergency.ReloadablePreferenceInterface;
import com.android.internal.logging.MetricsLogger;
import com.android.internal.logging.MetricsProto.MetricsEvent;

import java.util.Collections;
import java.util.Iterator;
import java.util.Set;

/**
 * Custom {@link PreferenceCategory} that deals with contacts being deleted from the contacts app.
 *
 * <p>Contacts are stored internally using their ContactsContract.CommonDataKinds.Phone.CONTENT_URI.
 */
public class EmergencyContactsPreference extends PreferenceCategory
        implements ReloadablePreferenceInterface,
        ContactPreference.RemoveContactPreferenceListener {

    /** Stores the emergency contact's ContactsContract.CommonDataKinds.Phone.CONTENT_URI */
    private Set<Uri> mEmergencyContacts = new ArraySet<Uri>();

    public EmergencyContactsPreference(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    protected void onSetInitialValue(boolean restorePersistedValue, Object defaultValue) {
        setEmergencyContacts(restorePersistedValue ?
                getPersistedEmergencyContacts() :
                deserializeAndFilterExisting((Set<String>) defaultValue));
    }

    @Override
    public void reloadFromPreference() {
        setEmergencyContacts(getPersistedEmergencyContacts());
    }

    @Override
    public boolean isNotSet() {
        return mEmergencyContacts.isEmpty();
    }

    @Override
    public void onRemoveContactPreference(ContactPreference contactPreference) {
        Uri newContact = contactPreference.getContactUri();
        if (mEmergencyContacts.contains(newContact)) {
            Set<Uri> updatedContacts = new ArraySet<Uri>((ArraySet<Uri>) mEmergencyContacts);
            if (updatedContacts.remove(newContact) && callChangeListener(updatedContacts)) {
                MetricsLogger.action(getContext(), MetricsEvent.ACTION_DELETE_EMERGENCY_CONTACT);
                setEmergencyContacts(updatedContacts);
            }
        }
    }

    /**
     * Adds a new emergency contact. The {@code contactUri} is the
     * ContactsContract.CommonDataKinds.Phone.CONTENT_URI corresponding to the
     * contact's selected phone number.
     */
    public void addNewEmergencyContact(Uri contactUri) {
        if (!mEmergencyContacts.contains(contactUri)) {
            Set<Uri> updatedContacts = new ArraySet<Uri>((ArraySet<Uri>) mEmergencyContacts);
            if (updatedContacts.add(contactUri) && callChangeListener(updatedContacts)) {
                MetricsLogger.action(getContext(), MetricsEvent.ACTION_ADD_EMERGENCY_CONTACT);
                setEmergencyContacts(updatedContacts);
            }
        }
    }

    private void setEmergencyContacts(Set<Uri> emergencyContacts) {
        if (mEmergencyContacts.equals(emergencyContacts)) {
            // Force reload
            for (int i = 0; i < getPreferenceCount(); i++) {
                ContactPreference contactPreference = (ContactPreference) getPreference(i);
                contactPreference.setUri(contactPreference.getContactUri());
            }
            return;
        }

        mEmergencyContacts = emergencyContacts;
        persistEmergencyContacts(emergencyContacts);
        notifyChanged();

        while (getPreferenceCount() - emergencyContacts.size() > 0) {
            removePreference(getPreference(0));
        }

        // Reload the preferences or add new ones if necessary
        Iterator<Uri> it = emergencyContacts.iterator();
        int i = 0;
        while (it.hasNext()) {
            if (i < getPreferenceCount()) {
                ContactPreference contactPreference = (ContactPreference) getPreference(i);
                contactPreference.setUri(it.next());
            } else {
                addContactPreference(it.next());
            }
            i++;
        }
    }

    private void addContactPreference(Uri contactUri) {
        final ContactPreference contactPreference = new ContactPreference(getContext(), contactUri);
        onBindContactView(contactPreference);
        addPreference(contactPreference);
    }

    /**
     * Called when {@code contactPreference} has been added to this category. You may now set
     * listeners.
     */
    protected void onBindContactView(final ContactPreference contactPreference) {
        contactPreference.setRemoveContactPreferenceListener(this);
        contactPreference
                .setOnPreferenceClickListener(
                        new Preference.OnPreferenceClickListener() {
                            @Override
                            public boolean onPreferenceClick(Preference preference) {
                                contactPreference.displayContact();
                                return true;
                            }
                        }
                );
    }

    private Set<Uri> getPersistedEmergencyContacts() {
        return deserializeAndFilterExisting(
                getPersistedStringSet(Collections.<String>emptySet()));
    }

    /**
     * Converts the strings to Uris and only keeps those corresponding to still existing contacts.
     */
    private Set<Uri> deserializeAndFilterExisting(Set<String> emergencyContactStrings) {
        Set<Uri> emergencyContacts = new ArraySet<Uri>(emergencyContactStrings.size());
        for (String emergencyContact : emergencyContactStrings) {
            Uri contactUri = Uri.parse(emergencyContact);
            if (EmergencyContactManager.isValidEmergencyContact(getContext(), contactUri)) {
                emergencyContacts.add(contactUri);
            }
        }

        // If not all contacts were added, then we need to overwrite the emergency contacts stored
        // in shared preferences. This deals with emergency contacts being deleted from contacts:
        // currently we have no way to being notified when this happens.
        if (emergencyContacts.size() != emergencyContactStrings.size()) {
            persistEmergencyContacts(emergencyContacts);
        }

        return emergencyContacts;
    }

    private void persistEmergencyContacts(Set<Uri> emergencyContacts) {
        Set<String> emergencyContactStrings = serialize(emergencyContacts);
        persistStringSet(emergencyContactStrings);
    }

    /** Converts the Uris to their string representation. */
    private Set<String> serialize(Set<Uri> emergencyContacts) {
        Set<String> emergencyContactStrings = new ArraySet<String>(emergencyContacts.size());
        for (Uri contactUri : emergencyContacts) {
            emergencyContactStrings.add(contactUri.toString());
        }
        return emergencyContactStrings;
    }
}