app_Settings/src/com/android/settings/accessibility/ToggleFeaturePreferenceFragment.java

/*
 * Copyright (C) 2013 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.accessibility;

import android.app.ActionBar;
import android.app.Activity;
import android.content.Intent;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceScreen;
import android.view.Gravity;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.accessibility.AccessibilityEvent;
import android.view.accessibility.AccessibilityManager;
import android.widget.TextView;

import com.android.settings.R;
import com.android.settings.SettingsPreferenceFragment;

public abstract class ToggleFeaturePreferenceFragment
        extends SettingsPreferenceFragment {

    protected ToggleSwitch mToggleSwitch;

    protected String mPreferenceKey;
    protected Preference mSummaryPreference;

    protected CharSequence mSettingsTitle;
    protected Intent mSettingsIntent;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        PreferenceScreen preferenceScreen = getPreferenceManager().createPreferenceScreen(
                getActivity());
        setPreferenceScreen(preferenceScreen);
        mSummaryPreference = new Preference(getActivity()) {
                @Override
            protected void onBindView(View view) {
                super.onBindView(view);
                TextView summaryView = (TextView) view.findViewById(R.id.summary);
                summaryView.setText(getSummary());
                sendAccessibilityEvent(summaryView);
            }

            private void sendAccessibilityEvent(View view) {
                // Since the view is still not attached we create, populate,
                // and send the event directly since we do not know when it
                // will be attached and posting commands is not as clean.
                AccessibilityManager accessibilityManager =
                        AccessibilityManager.getInstance(getActivity());
                if (accessibilityManager.isEnabled()) {
                    AccessibilityEvent event = AccessibilityEvent.obtain();
                    event.setEventType(AccessibilityEvent.TYPE_VIEW_FOCUSED);
                    view.onInitializeAccessibilityEvent(event);
                    view.dispatchPopulateAccessibilityEvent(event);
                    accessibilityManager.sendAccessibilityEvent(event);
                }
            }
        };
        mSummaryPreference.setPersistent(false);
        mSummaryPreference.setLayoutResource(R.layout.text_description_preference);
        preferenceScreen.addPreference(mSummaryPreference);
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        onInstallActionBarToggleSwitch();
        onProcessArguments(getArguments());
        // Set a transparent drawable to prevent use of the default one.
        getListView().setSelector(new ColorDrawable(Color.TRANSPARENT));
        getListView().setDivider(null);
    }

    @Override
    public void onDestroyView() {
        getActivity().getActionBar().setCustomView(null);
        mToggleSwitch.setOnBeforeCheckedChangeListener(null);
        super.onDestroyView();
    }

    protected abstract void onPreferenceToggled(String preferenceKey, boolean enabled);

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        super.onCreateOptionsMenu(menu, inflater);
        MenuItem menuItem = menu.add(mSettingsTitle);
        menuItem.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
        menuItem.setIntent(mSettingsIntent);
    }

    protected void onInstallActionBarToggleSwitch() {
        mToggleSwitch = createAndAddActionBarToggleSwitch(getActivity());
    }

    private ToggleSwitch createAndAddActionBarToggleSwitch(Activity activity) {
        ToggleSwitch toggleSwitch = new ToggleSwitch(activity);
        final int padding = activity.getResources().getDimensionPixelSize(
                R.dimen.action_bar_switch_padding);
        toggleSwitch.setPaddingRelative(0, 0, padding, 0);
        activity.getActionBar().setDisplayOptions(ActionBar.DISPLAY_SHOW_CUSTOM,
                ActionBar.DISPLAY_SHOW_CUSTOM);
        activity.getActionBar().setCustomView(toggleSwitch,
                new ActionBar.LayoutParams(ActionBar.LayoutParams.WRAP_CONTENT,
                        ActionBar.LayoutParams.WRAP_CONTENT,
                                Gravity.CENTER_VERTICAL | Gravity.END));
        return toggleSwitch;
    }

    protected void onProcessArguments(Bundle arguments) {
        // Key.
        mPreferenceKey = arguments.getString(AccessibilitySettings.EXTRA_PREFERENCE_KEY);
        // Enabled.
        final boolean enabled = arguments.getBoolean(AccessibilitySettings.EXTRA_CHECKED);
        mToggleSwitch.setCheckedInternal(enabled);
        // Title.
        PreferenceActivity activity = (PreferenceActivity) getActivity();
        if (!activity.onIsMultiPane() || activity.onIsHidingHeaders()) {
            String title = arguments.getString(AccessibilitySettings.EXTRA_TITLE);
            getActivity().setTitle(title);
        }
        // Summary.
        CharSequence summary = arguments.getCharSequence(AccessibilitySettings.EXTRA_SUMMARY);
        mSummaryPreference.setSummary(summary);
    }
}