PreferencesActivity with PreferenceScreen

PreferencesActivity

package pwr.rss.reader

import scala.collection.mutable.HashSet

import com.actionbarsherlock.app.SherlockPreferenceActivity
import com.actionbarsherlock.view.MenuItem

import android.content.SharedPreferences
import android.content.SharedPreferences.OnSharedPreferenceChangeListener
import android.os.Bundle
import android.preference.PreferenceManager
import PreferencesActivity._

object PreferencesActivity {
	final lazy val KEY_AUTO_REFRESH = "preference_auto_refresh"
	final lazy val KEY_REFRESH_PERIOD = "preference_refresh_period"
	final lazy val KEY_NOTIFICATIONS = "preferencescreen_notifications"
	final lazy val KEY_NOTIFICATIONS_LED = "preference_notifications_led"
	final lazy val KEY_NOTIFICATIONS_SOUND = "preference_notifications_sound"
	final lazy val KEY_NOTIFICATIONS_VIBRATIONS = "preference_notifications_vibrations"
	final lazy val KEY_AUTO_MARK_AS_READ = "preference_auto_mark_as_read"
	final lazy val KEY_CHECKED_RADIO_BUTTON = "preference_checked_radio"
	final lazy val KEY_SHOW_SELECTED_ONLY = "preference_show_selected_only"
	final lazy val KEY_KEEP_READ_FEEDS = "preference_keep_read_feeds"

	private final val DEFAULT_REFRESH_PERIOD = "10"
}

class PreferencesActivity extends SherlockPreferenceActivity with OnSharedPreferenceChangeListener {
	private lazy val sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this)
	private lazy val notificationsSet = new HashSet[String]

	private lazy val textViewRefreshPeriod = findPreference(KEY_REFRESH_PERIOD)
	private lazy val preferenceNotifications = findPreference(KEY_NOTIFICATIONS)

	override def onCreate(savedInstanceState: Bundle) = {
		super.onCreate(savedInstanceState)
		addPreferencesFromResource(R.xml.preferences)
		getSupportActionBar.setDisplayHomeAsUpEnabled(true)
	}

	override def onResume = {
		super.onResume
		sharedPreferences
			.registerOnSharedPreferenceChangeListener(this)

		configureRefreshPeriod
		configureNotificationsType
	}

	override def onPause = {
		super.onPause
		sharedPreferences
			.unregisterOnSharedPreferenceChangeListener(this)
	}

	private def configureRefreshPeriod = textViewRefreshPeriod.setSummary(getNotificationPeriod)

	private def getNotificationPeriod = {
		val refreshPeriodValue = sharedPreferences.getString(KEY_REFRESH_PERIOD, DEFAULT_REFRESH_PERIOD)
		val summaryRefreshPeriod_general = getString(R.string.preference_period_summary)
		val summaryRefreshPeriod_concrete = String.format(summaryRefreshPeriod_general, refreshPeriodValue.toString)
		summaryRefreshPeriod_concrete
	}

	def configureNotificationsType = {
		configureNotifications(KEY_NOTIFICATIONS_LED)
		configureNotifications(KEY_NOTIFICATIONS_SOUND)
		configureNotifications(KEY_NOTIFICATIONS_VIBRATIONS)

		preferenceNotifications.setSummary(getNotificationsSummary)
	}

	private def configureNotifications(key: String) = {
		val notificationPreference = findPreference(key)
		val notificationEnabled = sharedPreferences.getBoolean(key, false)
		val notificationType = notificationPreference.getTitle.toString

		if (notificationEnabled)
			notificationsSet += notificationType
		else
			notificationsSet -= notificationType

		preferenceNotifications.setSummary(getNotificationsSummary)
		onContentChanged
	}

	private def getNotificationsSummary =
		if (!notificationsSet.isEmpty)
			getString(R.string.preference_notifications_summary_checked) +
				getStringValuesFromSet(notificationsSet)
		else
			getString(R.string.preference_notifications_summary_unchecked)

	private def getStringValuesFromSet(notificationsSet: HashSet[String]) =
		notificationsSet.mkString(", ")

	override def onSharedPreferenceChanged(sharedPreferences: SharedPreferences, key: String) =
		key match {
			case `KEY_REFRESH_PERIOD` => configureRefreshPeriod
			case `KEY_NOTIFICATIONS_LED`
				| `KEY_NOTIFICATIONS_SOUND`
				| `KEY_NOTIFICATIONS_VIBRATIONS` => configureNotifications(key)
			case _ =>
		}

	override def onMenuItemSelected(featureId: Int, item: MenuItem) = {
		item.getItemId match {
			case android.R.id.home => finish
			case _ =>
		}
		true
	}
}

PreferencesLayout

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >

    <PreferenceCategory android:title="@string/preference_refreshing" >
        <CheckBoxPreference
            android:defaultValue="true"
            android:key="preference_auto_refresh"
            android:summary="@string/preference_auto_refresh_summary"
            android:title="@string/preference_auto_refresh" />

        <EditTextPreference
            android:defaultValue="10"
            android:dependency="preference_auto_refresh"
            android:inputType="number"
            android:key="preference_refresh_period"
            android:title="@string/preference_period" />
    </PreferenceCategory>
    <PreferenceCategory android:title="@string/preference_notifications" >
        <PreferenceScreen
            android:key="preferencescreen_notifications"
            android:title="@string/preference_notifications" >
            <CheckBoxPreference
                android:defaultValue="true"
                android:key="preference_notifications_led"
                android:summary="@string/preference_notifications_led_summary"
                android:title="@string/preference_notifications_led" />
            <CheckBoxPreference
                android:defaultValue="true"
                android:key="preference_notifications_sound"
                android:summary="@string/preference_notifications_sound_summary"
                android:title="@string/preference_notifications_sound" />
            <CheckBoxPreference
                android:defaultValue="true"
                android:key="preference_notifications_vibrations"
                android:summary="@string/preference_notifications_vibration_summary"
                android:title="@string/preference_notifications_vibration" />
        </PreferenceScreen>
    </PreferenceCategory>
    <PreferenceCategory android:title="@string/preference_extras" >
        <CheckBoxPreference
            android:defaultValue="true"
            android:key="preference_auto_mark_as_read"
            android:summary="@string/preference_auto_mark_as_read_summary"
            android:title="@string/preference_auto_mark_as_read" />
        <CheckBoxPreference
            android:defaultValue="true"
            android:key="preference_keep_read_feeds"
            android:summary="@string/preference_keep_read_feeds_summary"
            android:title="@string/preference_keep_read_feeds" />
    </PreferenceCategory>

</PreferenceScreen>