PreferencesActivity.java

/**
 * Copyright (C) 2013 Eesti Vabariigi Valimiskomisjon 
 * (Estonian National Electoral Committee), www.vvk.ee
 *
 * Written in 2013 by AS Finestmedia, www.finestmedia.ee
 *
 * Vote-verification application for Estonian Internet voting system
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * This file incorporates work covered by the following copyright and  
 * permission notice:  
 * 
 * Copyright (C) 2008 ZXing authors
 * 
 * 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 ee.vvk.ivotingverification.qr;

import java.util.ArrayList;
import java.util.Collection;

import android.content.SharedPreferences;
import android.content.SharedPreferences.OnSharedPreferenceChangeListener;
import android.os.Bundle;
import android.preference.CheckBoxPreference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceScreen;

/**
 * The main settings activity.
 * 
 * @author dswitkin@google.com (Daniel Switkin)
 */
public final class PreferencesActivity extends PreferenceActivity implements
		OnSharedPreferenceChangeListener {

	public static final String KEY_DECODE_1D = "preferences_decode_1D";
	public static final String KEY_DECODE_QR = "preferences_decode_QR";
	public static final String KEY_DECODE_DATA_MATRIX = "preferences_decode_Data_Matrix";
	public static final String KEY_CUSTOM_PRODUCT_SEARCH = "preferences_custom_product_search";

	public static final String KEY_REVERSE_IMAGE = "preferences_reverse_image";
	public static final String KEY_PLAY_BEEP = "preferences_play_beep";
	public static final String KEY_VIBRATE = "preferences_vibrate";
	public static final String KEY_COPY_TO_CLIPBOARD = "preferences_copy_to_clipboard";
	public static final String KEY_FRONT_LIGHT = "preferences_front_light";
	public static final String KEY_BULK_MODE = "preferences_bulk_mode";
	public static final String KEY_REMEMBER_DUPLICATES = "preferences_remember_duplicates";
	public static final String KEY_SUPPLEMENTAL = "preferences_supplemental";
	public static final String KEY_SEARCH_COUNTRY = "preferences_search_country";

	public static final String KEY_HELP_VERSION_SHOWN = "preferences_help_version_shown";

	private CheckBoxPreference decode1D;
	private CheckBoxPreference decodeQR;
	private CheckBoxPreference decodeDataMatrix;

	@Override
	protected void onCreate(Bundle icicle) {
		super.onCreate(icicle);

		PreferenceScreen preferences = getPreferenceScreen();
		preferences.getSharedPreferences()
				.registerOnSharedPreferenceChangeListener(this);
		decode1D = (CheckBoxPreference) preferences
				.findPreference(KEY_DECODE_1D);
		decodeQR = (CheckBoxPreference) preferences
				.findPreference(KEY_DECODE_QR);
		decodeDataMatrix = (CheckBoxPreference) preferences
				.findPreference(KEY_DECODE_DATA_MATRIX);
		disableLastCheckedPref();
	}

	@Override
	public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
			String key) {
		disableLastCheckedPref();
	}

	private void disableLastCheckedPref() {
		Collection<CheckBoxPreference> checked = new ArrayList<CheckBoxPreference>(
				3);
		if (decode1D.isChecked()) {
			checked.add(decode1D);
		}
		if (decodeQR.isChecked()) {
			checked.add(decodeQR);
		}
		if (decodeDataMatrix.isChecked()) {
			checked.add(decodeDataMatrix);
		}
		boolean disable = checked.size() < 2;
		CheckBoxPreference[] checkBoxPreferences = { decode1D, decodeQR,
				decodeDataMatrix };
		for (CheckBoxPreference pref : checkBoxPreferences) {
			pref.setEnabled(!(disable && checked.contains(pref)));
		}
	}
}