org.solovyev.android.LastTabSaver Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of android-common-samples Show documentation
There is a newer version: 1.1.18
Show newest version
/*
 * Copyright 2013 serso aka se.solovyev
 *
 * 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.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * Contact details
 *
 * Email: [email protected]
 * Site:  http://se.solovyev.org
 */

package org.solovyev.android;

import android.app.TabActivity;
import android.preference.PreferenceManager;
import android.widget.TabHost;
import org.solovyev.android.prefs.StringPreference;

import javax.annotation.Nonnull;

/**
 * User: serso
 * Date: 1/9/12
 * Time: 6:17 PM
 */

/**
 * This class saves the last opened tab in the tabHost to the SharedPreferences in order to reopen it after closing
 * The tab is defined by it's tab id and tab activity where it is hold => you can use the same tab ids in different tab activities
 */
public class LastTabSaver implements TabHost.OnTabChangeListener {

	// prefix of preference's key
	private static final String LAST_OPENED_TAB_P_KEY = "last_opened_tab_";

	// preference object
	@Nonnull
	private final StringPreference preference;

	// activity that holds tab host
	@Nonnull
	private final TabActivity tabActivity;

	/**
	 * Constructor applies saved preference value on tabHost returned by  android.app.TabActivity#getTabHost() method
	 * and registers as onTabChangeListener
	 *
	 * @param tabActivity  tab activity
	 * @param defaultTabId default tab (if no preference value is not defined)
	 */
	public LastTabSaver(@Nonnull TabActivity tabActivity, @Nonnull String defaultTabId) {
		this.tabActivity = tabActivity;
		this.preference = StringPreference.of(getPreferenceKey(), defaultTabId);

		final TabHost tabHost = tabActivity.getTabHost();
		tabHost.setCurrentTabByTag(this.getLastOpenedTabId());
		tabHost.setOnTabChangedListener(this);
	}

	/**
	 * Method must be invoked on android.app.Activity#onDestroy() method of tab activity
	 */
	public void destroy() {
		final TabHost tabHost = tabActivity.getTabHost();
		tabHost.setOnTabChangedListener(null);
	}

	@Override
	public void onTabChanged(String tabId) {
		preference.putPreference(PreferenceManager.getDefaultSharedPreferences(tabActivity), tabId);
	}

	@Nonnull
	public String getLastOpenedTabId() {
		return preference.getPreference(PreferenceManager.getDefaultSharedPreferences(tabActivity));
	}

	@Nonnull
	private String getPreferenceKey() {
		return LAST_OPENED_TAB_P_KEY + tabActivity.getClass().getName();
	}
}