src/com/android/settings/gestures/AssistGesturePreferenceController.java

/*
 * 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.gestures;

import android.content.Context;
import android.net.Uri;
import android.provider.Settings;
import android.support.v7.preference.Preference;
import android.support.v7.preference.PreferenceScreen;

import com.android.settings.applications.assist.AssistSettingObserver;
import com.android.settings.overlay.FeatureFactory;
import com.android.settingslib.core.lifecycle.Lifecycle;
import com.android.settingslib.core.lifecycle.events.OnPause;
import com.android.settingslib.core.lifecycle.events.OnResume;

import java.util.Arrays;
import java.util.List;

public class AssistGesturePreferenceController extends GesturePreferenceController
        implements OnPause, OnResume {

    private static final String PREF_KEY_VIDEO = "gesture_assist_video";
    private final String mAssistGesturePrefKey;

    private final AssistGestureFeatureProvider mFeatureProvider;
    private final SettingObserver mSettingObserver;
    private boolean mWasAvailable;

    private PreferenceScreen mScreen;
    private Preference mPreference;

    public AssistGesturePreferenceController(Context context, Lifecycle lifecycle, String key) {
        super(context, lifecycle);
        mFeatureProvider = FeatureFactory.getFactory(context).getAssistGestureFeatureProvider();
        mSettingObserver = new SettingObserver();
        mWasAvailable = isAvailable();
        mAssistGesturePrefKey = key;
    }

    @Override
    public boolean isAvailable() {
        return mFeatureProvider.isSupported(mContext);
    }

    @Override
    public void displayPreference(PreferenceScreen screen) {
        mScreen = screen;
        mPreference = screen.findPreference(getPreferenceKey());
        // Call super last or AbstractPreferenceController might remove the preference from the
        // screen (if !isAvailable()) before we can save a reference to it.
        super.displayPreference(screen);
    }

    @Override
    public void onResume() {
        mSettingObserver.register(mContext.getContentResolver(), true /* register */);
        if (mWasAvailable != isAvailable()) {
            // Only update the preference visibility if the availability has changed -- otherwise
            // the preference may be incorrectly added to screens with collapsed sections.
            updatePreference();
            mWasAvailable = isAvailable();
        }
    }

    @Override
    public void onPause() {
        mSettingObserver.register(mContext.getContentResolver(), false /* register */);
    }

    private void updatePreference() {
        if (mPreference == null) {
            return;
        }

        if (isAvailable()) {
            if (mScreen.findPreference(getPreferenceKey()) == null) {
                mScreen.addPreference(mPreference);
            }
        } else {
            mScreen.removePreference(mPreference);
        }
    }

    @Override
    public boolean onPreferenceChange(Preference preference, Object newValue) {
        final boolean enabled = (boolean) newValue;
        Settings.Secure.putInt(mContext.getContentResolver(),
                Settings.Secure.ASSIST_GESTURE_ENABLED, enabled ? 1 : 0);
        return true;
    }

    @Override
    protected String getVideoPrefKey() {
        return PREF_KEY_VIDEO;
    }

    @Override
    public String getPreferenceKey() {
        return mAssistGesturePrefKey;
    }

    @Override
    protected boolean isSwitchPrefEnabled() {
        final int assistGestureEnabled = Settings.Secure.getInt(mContext.getContentResolver(),
                Settings.Secure.ASSIST_GESTURE_ENABLED, 1);
        return assistGestureEnabled != 0;
    }

    class SettingObserver extends AssistSettingObserver {

        private final Uri ASSIST_GESTURE_ENABLED_URI =
                Settings.Secure.getUriFor(Settings.Secure.ASSIST_GESTURE_ENABLED);

        @Override
        protected List<Uri> getSettingUris() {
            return Arrays.asList(ASSIST_GESTURE_ENABLED_URI);
        }

        @Override
        public void onSettingChange() {
            if (mWasAvailable != isAvailable()) {
                updatePreference();
                mWasAvailable = isAvailable();
            }
        }
    }
}