From 4a2511b93c41c37b48ec45ef91bb2e5fd5f1f2a5 Mon Sep 17 00:00:00 2001
From: Sergey Solovyev <se.solovyev@gmail.com>
Date: Sun, 25 Dec 2011 02:54:47 +0400
Subject: [PATCH] release notes + welcome window

---
 AndroidManifest.xml                           | 12 ++-
 res/layout/calc_multiplication_button.xml     |  2 +-
 res/layout/release_notes.xml                  | 28 +++++++
 res/values-ru/text_about.xml                  | 47 ++++++++++++
 res/values-ru/text_strings.xml                |  5 ++
 res/values/default_values.xml                 |  3 +
 res/values/text_about.xml                     | 47 ++++++++++++
 res/values/text_strings.xml                   |  5 ++
 res/xml/main_preferences.xml                  |  6 ++
 .../calculator/CalculatorActivity.java        | 41 ++++++++++-
 .../CalculatorActivityLauncher.java           |  7 +-
 .../CalculatorAboutActivity.java}             | 12 +--
 .../about/CalculatorAboutTabActivity.java     | 36 +++++++++
 .../about/CalculatorReleaseNotesActivity.java | 73 +++++++++++++++++++
 ...ty.java => CalculatorHelpTabActivity.java} |  2 +-
 .../history/CalculatorHistoryActivity.java    | 21 +-----
 .../android/view/prefs/AndroidUtils.java      | 37 ++++++++++
 .../android/view/prefs/ResourceCache.java     | 40 +++++++---
 .../model/CalculatorEngineTest.java           |  2 +-
 19 files changed, 382 insertions(+), 44 deletions(-)
 create mode 100644 res/layout/release_notes.xml
 rename src/main/java/org/solovyev/android/calculator/{AboutActivity.java => about/CalculatorAboutActivity.java} (74%)
 create mode 100644 src/main/java/org/solovyev/android/calculator/about/CalculatorAboutTabActivity.java
 create mode 100644 src/main/java/org/solovyev/android/calculator/about/CalculatorReleaseNotesActivity.java
 rename src/main/java/org/solovyev/android/calculator/help/{HelpActivity.java => CalculatorHelpTabActivity.java} (96%)

diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 7c9c4716..38c9b3b2 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -41,11 +41,19 @@
 				  a:label="@string/c_saved_history"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".AboutActivity"
+		<activity a:name=".about.CalculatorAboutTabActivity"
 				  a:label="@string/c_about"
 				  a:configChanges="orientation|keyboardHidden"/>
 
-		<activity a:name=".help.HelpActivity"
+		<activity a:name=".about.CalculatorAboutActivity"
+				  a:label="@string/c_about"
+				  a:configChanges="orientation|keyboardHidden"/>
+
+		<activity a:name=".about.CalculatorReleaseNotesActivity"
+				  a:label="@string/c_about"
+				  a:configChanges="orientation|keyboardHidden"/>
+
+		<activity a:name=".help.CalculatorHelpTabActivity"
 				  a:label="@string/c_help"
 				  a:configChanges="orientation|keyboardHidden"/>
 
diff --git a/res/layout/calc_multiplication_button.xml b/res/layout/calc_multiplication_button.xml
index 84119e89..603204b6 100644
--- a/res/layout/calc_multiplication_button.xml
+++ b/res/layout/calc_multiplication_button.xml
@@ -12,7 +12,7 @@
 													   a:text="×"
 													   c:textUp="^"
 													   c:textDown="^2"
+													   c:textLeft="PI"
 													   style="?digitButtonStyle"
 													   c:directionTextScale="0.5"
-
 													   a:onClick="digitButtonClickHandler"/>
\ No newline at end of file
diff --git a/res/layout/release_notes.xml b/res/layout/release_notes.xml
new file mode 100644
index 00000000..911ff731
--- /dev/null
+++ b/res/layout/release_notes.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<!--
+  ~ Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+  ~ For more information, please, contact se.solovyev@gmail.com
+  ~ or visit http://se.solovyev.org
+  -->
+
+<LinearLayout xmlns:a="http://schemas.android.com/apk/res/android"
+			  a:orientation="vertical"
+			  a:layout_width="fill_parent"
+			  a:layout_height="fill_parent"
+			  a:background="#ff000000">
+
+	<TextView
+			a:id="@+id/releaseNotesTextView"
+			a:layout_height="fill_parent"
+			a:layout_width="fill_parent"
+			a:layout_weight="1"
+			a:gravity="top|left"
+			a:scrollbars="vertical"
+			style="@style/about_style"/>
+
+	<!--
+			a:scrollbarFadeDuration="0" is not support in  android_1.6_compatibility
+			-->
+
+</LinearLayout>
\ No newline at end of file
diff --git a/res/values-ru/text_about.xml b/res/values-ru/text_about.xml
index 4ba996eb..6f818919 100644
--- a/res/values-ru/text_about.xml
+++ b/res/values-ru/text_about.xml
@@ -23,4 +23,51 @@
 		<a href="http://www.achartengine.org/">AChartEngine</a>
 	</string>
 
+	<string name="c_release_notes">Замечания к выпуску</string>
+	<string name="c_release_notes_for_title">"Замечания к выпуску версии "</string>
+
+	<string name="c_release_notes_for_4">
+		1. Отклик на нажатие\n
+		2. Две раскладки кнопок\n
+		3. Новые константы\n
+		4. Сообщение об ошибке показывается реже
+	</string>
+
+	<string name="c_release_notes_for_5">
+		1. Экран со всеми доступными функциями\n
+		2. Поддержка десятичного логарифма, факториала, функций сравнения\n
+		3. Настройки отклика
+	</string>
+
+	<string name="c_release_notes_for_6">
+		1. Сохранение констант в два клика (используйте +π кнопку)\n
+		2. Размер результата автоматически масштабируется\n
+		3. Исправлена ошибка с отсутствием результата в Xperia Ray\n
+		4. Исправлена ошибка расчёта двойного факториала\n
+		5. Добавлены градусы (используйте °, например, 30° и результат будет автоматически переведён в радианы)
+	</string>
+
+	<string name="c_release_notes_for_7">
+		1. Поддержка ввода чисел в научной нотации (2.3E2)\n
+		2. Добавлены функции: deg(), rad() для перевода радианов в градусы и наоборот\n
+		3. Добавлена поддержка установки приложения на карту памяти\n
+		4. Добавлена поддержка сохранить целое выражение как константу (например, наберите ln(6t), нажмите +π, введите имя и сохраните)\n
+		5. Исправлена проблема с функцией abs() и комплексным аргументом\n
+		6. Исправлена проблема с отображением результата
+	</string>
+
+	<string name="c_release_notes_for_8">
+		1. Исправлена проблема с i^3\n
+		2. Исправлено падение при использовании большого числа скобочек
+	</string>
+
+	<string name="c_release_notes_for_20">
+		1. Поддержка свайпа влево, вправо\n
+		2. Расширенная история: сохранение, удаление, копирование истории (используйте длинное нажатие)\n
+		3. Добавлен испанский язык\n
+		4. Полная поддержка систем счисления (dec, hex, oct, bin)\n
+		5. !!!: Решение проблемы знака произведения на некоторых устройствах. Если у вас странные символы вместо × - измените знак произведения * в настройках приложения\n
+		6. Исправлено: правильное вычисление двойного факториала, 20x, e^(pi*i)+1 и др.
+	</string>
+
 </resources>
\ No newline at end of file
diff --git a/res/values-ru/text_strings.xml b/res/values-ru/text_strings.xml
index f5caab72..727d5d0b 100644
--- a/res/values-ru/text_strings.xml
+++ b/res/values-ru/text_strings.xml
@@ -153,4 +153,9 @@
 	<string name="c_copy_description">Копироват описание</string>
 	<string name="c_copy_value">Копировать значение</string>
 
+	<string name="c_first_start_text">Спасибо за выбор Калькулятора++!</string>
+
+	<string name="c_calc_show_release_notes_title">Показывать замечания к выпуску</string>
+	<string name="c_calc_show_release_notes_summary">Определяет показывать или нет всплывающее окно с замечаниями к выпуску после обновления новой версии</string>
+
 </resources>
\ No newline at end of file
diff --git a/res/values/default_values.xml b/res/values/default_values.xml
index 989ad97c..403d9b02 100644
--- a/res/values/default_values.xml
+++ b/res/values/default_values.xml
@@ -24,6 +24,9 @@
 	<string name="p_calc_haptic_feedback_key">org.solovyev.android.calculator.CalculatorModel_haptic_feedback</string>
 	<string name="p_calc_haptic_feedback">false</string>
 
+	<string name="p_calc_show_release_notes_key">org.solovyev.android.calculator.CalculatorActivity_show_release_notes</string>
+	<string name="p_calc_show_release_notes">true</string>
+
 	<string name="p_calc_round_result_key">org.solovyev.android.calculator.CalculatorModel_round_result</string>
 	<string name="p_calc_round_result">true</string>
 
diff --git a/res/values/text_about.xml b/res/values/text_about.xml
index aa323912..18884bbf 100644
--- a/res/values/text_about.xml
+++ b/res/values/text_about.xml
@@ -23,4 +23,51 @@
 		<a href="http://www.achartengine.org/">AChartEngine</a>
 	</string>
 
+	<string name="c_release_notes">Release notes</string>
+	<string name="c_release_notes_for_title">"Release notes for version "</string>
+	
+	<string name="c_release_notes_for_4">
+		1. Haptic feedback\n
+		2. Two layouts: calculator and cellphone\n
+		3. New constants\n
+		4. ERROR message is not so often now
+	</string>
+
+	<string name="c_release_notes_for_5">
+		1. Screen with all functions\n
+		2. Added support for decimal logarithm, factorial, comparison functions\n
+		3. Haptic feedback duration preference
+	</string>
+
+	<string name="c_release_notes_for_6">
+		1. Saving constants in two clicks (use +π button)\n
+		2. Result size is auto adjusted to fill all spare space\n
+		3. Fix for Xperia Ray blank result\n
+		4. Double factorial fix\n
+		5. Degrees added (use °: e.g. 30° and result will be converted into radians)
+	</string>
+
+	<string name="c_release_notes_for_7">
+		1. Support for entering numbers in scientific notation (2.3E2)\n
+		2. Added functions: deg(), rad() to convert from radians to degrees and vice versa\n
+		3. Added support for installing application on sd card\n
+		4. Added possibility to save entire expression as constant (e.g. type ln(6t), press +π button, enter name and save)\n
+		5. Fixed bug with abs() function and complex argument\n
+		6. Fixed bug with displaying result
+	</string>
+
+	<string name="c_release_notes_for_8">
+		1. Fixed bug with i^3\n
+		2. Fixed crash in case of many brackets
+	</string>
+
+	<string name="c_release_notes_for_20">
+		1. New swipe actions (left, right)\n
+		2. Extended history: save, remove, copy, use from history screen (use long click for additional actions)\n
+		3. Added Spanish language\n
+		4. Full numeral base support (dec, hex, oct, bin)\n
+		5. !!!: Fix for multiplication sign on some devices - if you have strange symbols instead of × - go to the settings and change multiplication sign to *\n
+		6. Bug fixes: correct double factorial calculation, 20x fix, e^(pi*i)+1 fix and others
+	</string>
+
 </resources>
\ No newline at end of file
diff --git a/res/values/text_strings.xml b/res/values/text_strings.xml
index d3eb9c6d..abab7026 100644
--- a/res/values/text_strings.xml
+++ b/res/values/text_strings.xml
@@ -153,4 +153,9 @@
 	<string name="c_copy_description">Copy description</string>
 	<string name="c_copy_value">Copy value</string>
 
+	<string name="c_first_start_text">Thank you for choosing Calculator++!</string>
+
+	<string name="c_calc_show_release_notes_title">Show release notes</string>
+	<string name="c_calc_show_release_notes_summary">Defines if release notes popup window should appear after update to the new version</string>
+
 </resources>
\ No newline at end of file
diff --git a/res/xml/main_preferences.xml b/res/xml/main_preferences.xml
index d33e2a38..96d6e62a 100644
--- a/res/xml/main_preferences.xml
+++ b/res/xml/main_preferences.xml
@@ -86,6 +86,12 @@
 				range:steps="10"
 				range:boundaries="10;500"/>
 
+		<android.preference.CheckBoxPreference
+				a:key="@string/p_calc_show_release_notes_key"
+				a:summary="@string/c_calc_show_release_notes_summary"
+				a:title="@string/c_calc_show_release_notes_title"
+				a:defaultValue="true"/>
+
 <!--	  <org.solovyev.android.view.prefs.FloatRangeSeekBarPreference
 			  a:key="@string/p_drag_duration_key"
 			  a:title="Duration of drag event"
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java b/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
index c31ce90c..1815e6ef 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
@@ -15,6 +15,7 @@ import android.os.Bundle;
 import android.os.Vibrator;
 import android.preference.PreferenceManager;
 import android.text.ClipboardManager;
+import android.text.Html;
 import android.text.method.LinkMovementMethod;
 import android.util.Log;
 import android.util.TypedValue;
@@ -26,15 +27,18 @@ import jscl.AngleUnit;
 import jscl.NumeralBase;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.solovyev.android.calculator.about.CalculatorReleaseNotesActivity;
 import org.solovyev.android.calculator.history.CalculatorHistory;
 import org.solovyev.android.calculator.history.CalculatorHistoryState;
 import org.solovyev.android.calculator.math.MathType;
 import org.solovyev.android.calculator.model.CalculatorEngine;
 import org.solovyev.android.view.FontSizeAdjuster;
+import org.solovyev.android.view.prefs.AndroidUtils;
 import org.solovyev.android.view.prefs.ResourceCache;
 import org.solovyev.android.view.widgets.*;
 import org.solovyev.common.utils.Announcer;
 import org.solovyev.common.utils.Point2d;
+import org.solovyev.common.utils.StringUtils;
 import org.solovyev.common.utils.history.HistoryAction;
 
 import java.text.DecimalFormatSymbols;
@@ -44,6 +48,13 @@ import java.util.Map;
 public class CalculatorActivity extends Activity implements FontSizeAdjuster, SharedPreferences.OnSharedPreferenceChangeListener {
 
 	private static final int HVGA_WIDTH_PIXELS = 320;
+	
+	@NotNull
+	public static final String APP_VERSION_P_KEY = "application.version";
+
+	@NotNull
+	public static final String SHOW_RELEASE_NOTES_P_KEY = "org.solovyev.android.calculator.CalculatorActivity_show_release_notes";
+	public static final boolean SHOW_RELEASE_NOTES_P_DEFAULT = true;
 
 	@NotNull
 	private final Announcer<DragPreferencesChangeListener> dpclRegister = new Announcer<DragPreferencesChangeListener>(DragPreferencesChangeListener.class);
@@ -348,9 +359,37 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 
 	private synchronized void firstTimeInit(@NotNull SharedPreferences preferences) {
 		if (!initialized) {
-			ResourceCache.instance.init(R.id.class, this);
+			
+			final int savedVersion = preferences.getInt(APP_VERSION_P_KEY, -1);
+			final int appVersion = AndroidUtils.getAppVersionCode(this, CalculatorActivity.class.getPackage().getName());
+			
+			final SharedPreferences.Editor pEditor = preferences.edit();
+			pEditor.putInt(APP_VERSION_P_KEY, appVersion);
+			pEditor.commit();
 
+			if (savedVersion == -1) {
+				// new start
+				final AlertDialog.Builder builder = new AlertDialog.Builder(this).setMessage(R.string.c_first_start_text);
+				builder.setPositiveButton(android.R.string.ok, null);
+				builder.create().show();
+			} else {
+				if (savedVersion < appVersion) {
+					final boolean showReleaseNotes = preferences.getBoolean(SHOW_RELEASE_NOTES_P_KEY, SHOW_RELEASE_NOTES_P_DEFAULT);
+					if (showReleaseNotes) {
+						final String releaseNotes = CalculatorReleaseNotesActivity.getReleaseNotes(this, savedVersion + 1);
+						if (!StringUtils.isEmpty(releaseNotes)) {
+							final AlertDialog.Builder builder = new AlertDialog.Builder(this).setMessage(Html.fromHtml(releaseNotes));
+							builder.setPositiveButton(android.R.string.ok, null);
+							builder.setTitle(R.string.c_release_notes);
+							builder.create().show();
+						}
+					}
+				}
+			}
+
+			ResourceCache.instance.init(R.id.class, this);
 			CalculatorEngine.instance.init(this, preferences);
+
 			initialized = true;
 		}
 	}
diff --git a/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java b/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java
index 03fcde54..ea9481e0 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java
@@ -7,7 +7,8 @@ import jscl.math.Generic;
 import jscl.math.function.Constant;
 import org.achartengine.ChartFactory;
 import org.jetbrains.annotations.NotNull;
-import org.solovyev.android.calculator.help.HelpActivity;
+import org.solovyev.android.calculator.about.CalculatorAboutTabActivity;
+import org.solovyev.android.calculator.help.CalculatorHelpTabActivity;
 import org.solovyev.android.calculator.history.CalculatorHistoryActivity;
 import org.solovyev.android.calculator.math.edit.CalculatorFunctionsActivity;
 import org.solovyev.android.calculator.math.edit.CalculatorOperatorsActivity;
@@ -27,7 +28,7 @@ public class CalculatorActivityLauncher {
 	}
 
 	public static void showHelp(@NotNull final Context context) {
-		context.startActivity(new Intent(context, HelpActivity.class));
+		context.startActivity(new Intent(context, CalculatorHelpTabActivity.class));
 	}
 
 	public static void showSettings(@NotNull final Context context) {
@@ -35,7 +36,7 @@ public class CalculatorActivityLauncher {
 	}
 
 	public static void showAbout(@NotNull final Context context) {
-		context.startActivity(new Intent(context, AboutActivity.class));
+		context.startActivity(new Intent(context, CalculatorAboutTabActivity.class));
 	}
 
 	public static void showFunctions(@NotNull final Context context) {
diff --git a/src/main/java/org/solovyev/android/calculator/AboutActivity.java b/src/main/java/org/solovyev/android/calculator/about/CalculatorAboutActivity.java
similarity index 74%
rename from src/main/java/org/solovyev/android/calculator/AboutActivity.java
rename to src/main/java/org/solovyev/android/calculator/about/CalculatorAboutActivity.java
index 0fb25b9b..0214140b 100644
--- a/src/main/java/org/solovyev/android/calculator/AboutActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/about/CalculatorAboutActivity.java
@@ -1,23 +1,24 @@
 /*
  * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
  * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
  */
 
-package org.solovyev.android.calculator;
+package org.solovyev.android.calculator.about;
 
 import android.app.Activity;
 import android.os.Bundle;
-import android.text.Html;
 import android.text.method.LinkMovementMethod;
 import android.widget.TextView;
 import org.jetbrains.annotations.Nullable;
+import org.solovyev.android.calculator.R;
 
 /**
  * User: serso
- * Date: 9/16/11
- * Time: 11:52 PM
+ * Date: 12/24/11
+ * Time: 11:55 PM
  */
-public class AboutActivity extends Activity {
+public class CalculatorAboutActivity extends Activity {
 
 	@Override
 	public void onCreate(@Nullable Bundle savedInstanceState) {
@@ -26,6 +27,5 @@ public class AboutActivity extends Activity {
 
 		final TextView about = (TextView) findViewById(R.id.aboutTextView);
 		about.setMovementMethod(LinkMovementMethod.getInstance());
-
 	}
 }
diff --git a/src/main/java/org/solovyev/android/calculator/about/CalculatorAboutTabActivity.java b/src/main/java/org/solovyev/android/calculator/about/CalculatorAboutTabActivity.java
new file mode 100644
index 00000000..17ee9195
--- /dev/null
+++ b/src/main/java/org/solovyev/android/calculator/about/CalculatorAboutTabActivity.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ */
+
+package org.solovyev.android.calculator.about;
+
+import android.app.TabActivity;
+import android.os.Bundle;
+import android.widget.TabHost;
+import org.jetbrains.annotations.Nullable;
+import org.solovyev.android.calculator.R;
+import org.solovyev.android.view.prefs.AndroidUtils;
+
+/**
+ * User: serso
+ * Date: 9/16/11
+ * Time: 11:52 PM
+ */
+public class CalculatorAboutTabActivity extends TabActivity {
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+
+		setContentView(R.layout.tabs);
+
+		final TabHost tabHost = getTabHost();
+
+		AndroidUtils.addTab(this, tabHost, "about", R.string.c_about, CalculatorAboutActivity.class);
+		AndroidUtils.addTab(this, tabHost, "release_notes", R.string.c_release_notes, CalculatorReleaseNotesActivity.class);
+
+		tabHost.setCurrentTab(0);
+		AndroidUtils.centerAndWrapTabsFor(tabHost);
+	}
+}
diff --git a/src/main/java/org/solovyev/android/calculator/about/CalculatorReleaseNotesActivity.java b/src/main/java/org/solovyev/android/calculator/about/CalculatorReleaseNotesActivity.java
new file mode 100644
index 00000000..f1b42eb6
--- /dev/null
+++ b/src/main/java/org/solovyev/android/calculator/about/CalculatorReleaseNotesActivity.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2009-2011. Created by serso aka se.solovyev.
+ * For more information, please, contact se.solovyev@gmail.com
+ * or visit http://se.solovyev.org
+ */
+
+package org.solovyev.android.calculator.about;
+
+import android.app.Activity;
+import android.content.Context;
+import android.os.Bundle;
+import android.text.Html;
+import android.text.method.LinkMovementMethod;
+import android.widget.TextView;
+import org.jetbrains.annotations.NotNull;
+import org.solovyev.android.calculator.CalculatorActivity;
+import org.solovyev.android.calculator.R;
+import org.solovyev.android.view.prefs.AndroidUtils;
+import org.solovyev.android.view.prefs.ResourceCache;
+import org.solovyev.common.utils.StringUtils;
+
+/**
+ * User: serso
+ * Date: 12/25/11
+ * Time: 12:00 AM
+ */
+public class CalculatorReleaseNotesActivity extends Activity {
+
+	@Override
+	protected void onCreate(Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+
+		setContentView(R.layout.release_notes);
+
+		final TextView releaseNotes = (TextView) findViewById(R.id.releaseNotesTextView);
+		releaseNotes.setMovementMethod(LinkMovementMethod.getInstance());
+
+		releaseNotes.setText(Html.fromHtml(getReleaseNotes(this)));
+			
+
+	}
+
+	@NotNull
+	public static String getReleaseNotes(@NotNull Context context) {
+		return getReleaseNotes(context, 0);
+	}
+
+	@NotNull
+	public static String getReleaseNotes(@NotNull Context context, int minVersion) {
+		final StringBuilder result = new StringBuilder();
+
+		final String releaseNotesForTitle = context.getString(R.string.c_release_notes_for_title);
+		final int version = AndroidUtils.getAppVersionCode(context, CalculatorActivity.class.getPackage().getName());
+
+		boolean first = true;
+		for ( int i = version; i >= minVersion; i-- ) {
+			String releaseNotesForVersion = ResourceCache.instance.getCaption("c_release_notes_for_" + i);
+			if (!StringUtils.isEmpty(releaseNotesForVersion)){
+				assert releaseNotesForVersion != null;
+				if ( !first ) {
+					result.append("<br/><br/>");
+				} else {
+					first = false;
+				}
+				releaseNotesForVersion = releaseNotesForVersion.replace("\n", "<br/>");
+				result.append("<b>").append(releaseNotesForTitle).append(i).append("</b><br/>");
+				result.append(releaseNotesForVersion);
+			}
+		}
+
+		return result.toString();
+	}
+}
diff --git a/src/main/java/org/solovyev/android/calculator/help/HelpActivity.java b/src/main/java/org/solovyev/android/calculator/help/CalculatorHelpTabActivity.java
similarity index 96%
rename from src/main/java/org/solovyev/android/calculator/help/HelpActivity.java
rename to src/main/java/org/solovyev/android/calculator/help/CalculatorHelpTabActivity.java
index 85ec2f71..25dc9e56 100644
--- a/src/main/java/org/solovyev/android/calculator/help/HelpActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/help/CalculatorHelpTabActivity.java
@@ -21,7 +21,7 @@ import org.solovyev.android.view.prefs.AndroidUtils;
  * Date: 11/19/11
  * Time: 11:35 AM
  */
-public class HelpActivity extends TabActivity {
+public class CalculatorHelpTabActivity extends TabActivity {
 
 	@Override
 	public void onCreate(@Nullable Bundle savedInstanceState) {
diff --git a/src/main/java/org/solovyev/android/calculator/history/CalculatorHistoryActivity.java b/src/main/java/org/solovyev/android/calculator/history/CalculatorHistoryActivity.java
index d1065b39..9c4410cc 100644
--- a/src/main/java/org/solovyev/android/calculator/history/CalculatorHistoryActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/history/CalculatorHistoryActivity.java
@@ -6,12 +6,9 @@
 
 package org.solovyev.android.calculator.history;
 
-import android.app.Activity;
 import android.app.TabActivity;
-import android.content.Intent;
 import android.os.Bundle;
 import android.widget.TabHost;
-import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.calculator.R;
 import org.solovyev.android.view.prefs.AndroidUtils;
@@ -31,26 +28,12 @@ public class CalculatorHistoryActivity extends TabActivity {
 
 		final TabHost tabHost = getTabHost();
 
-		createTab(tabHost, "saved_history", R.string.c_saved_history, SavedHistoryActivityTab.class);
-		createTab(tabHost, "history", R.string.c_history, HistoryActivityTab.class);
+		AndroidUtils.addTab(this, tabHost, "saved_history", R.string.c_saved_history, SavedHistoryActivityTab.class);
+		AndroidUtils.addTab(this, tabHost, "history", R.string.c_history, HistoryActivityTab.class);
 
 		tabHost.setCurrentTab(0);
 
         AndroidUtils.centerAndWrapTabsFor(tabHost);
 	}
 
-	private void createTab(@NotNull TabHost tabHost,
-						   @NotNull String tabId,
-						   int tabCaptionId,
-						   @NotNull Class<? extends Activity> activityClass) {
-
-		TabHost.TabSpec spec;
-
-		final Intent intent = new Intent().setClass(this, activityClass);
-
-		// Initialize a TabSpec for each tab and add it to the TabHost
-		spec = tabHost.newTabSpec(tabId).setIndicator(this.getString(tabCaptionId)).setContent(intent);
-
-		tabHost.addTab(spec);
-	}
 }
diff --git a/src/main/java/org/solovyev/android/view/prefs/AndroidUtils.java b/src/main/java/org/solovyev/android/view/prefs/AndroidUtils.java
index 2d369309..4827aa8c 100644
--- a/src/main/java/org/solovyev/android/view/prefs/AndroidUtils.java
+++ b/src/main/java/org/solovyev/android/view/prefs/AndroidUtils.java
@@ -6,6 +6,10 @@
 
 package org.solovyev.android.view.prefs;
 
+import android.app.Activity;
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.PackageManager;
 import android.view.Gravity;
 import android.view.View;
 import android.view.ViewGroup;
@@ -52,4 +56,37 @@ public final class AndroidUtils {
             }
         }
     }
+
+	public static void addTab(@NotNull Context context,
+							  @NotNull TabHost tabHost,
+							  @NotNull String tabId,
+							  int tabCaptionId,
+							  @NotNull Class<? extends Activity> activityClass) {
+
+		TabHost.TabSpec spec;
+
+		final Intent intent = new Intent().setClass(context, activityClass);
+
+		// Initialize a TabSpec for each tab and add it to the TabHost
+		spec = tabHost.newTabSpec(tabId).setIndicator(context.getString(tabCaptionId)).setContent(intent);
+
+		tabHost.addTab(spec);
+	}
+
+
+	/**
+	 * @param context context
+	 * @param appPackageName - full name of the package of an app, 'com.example.app' for example.
+	 * @return version number we are currently in
+	 */
+	public static int getAppVersionCode(@NotNull Context context, @NotNull String appPackageName) {
+		try {
+			return context.getPackageManager().getPackageInfo(appPackageName, 0).versionCode;
+		} catch (PackageManager.NameNotFoundException e) {
+			// App not installed!
+		}
+		return -1;
+	}
+
 }
+
diff --git a/src/main/java/org/solovyev/android/view/prefs/ResourceCache.java b/src/main/java/org/solovyev/android/view/prefs/ResourceCache.java
index 7a19ddba..1a3276fb 100644
--- a/src/main/java/org/solovyev/android/view/prefs/ResourceCache.java
+++ b/src/main/java/org/solovyev/android/view/prefs/ResourceCache.java
@@ -8,6 +8,7 @@ package org.solovyev.android.view.prefs;
 
 import android.app.Activity;
 import android.content.Context;
+import android.content.res.Configuration;
 import android.content.res.Resources;
 import android.util.Log;
 import android.view.View;
@@ -84,24 +85,43 @@ public enum ResourceCache {
 		if (!initialized(locale)) {
 			final Map<String, String> captionsByLanguage = new HashMap<String, String>();
 
-			for (Field field : resourceClass.getDeclaredFields()) {
-				int modifiers = field.getModifiers();
-				if (Modifier.isFinal(modifiers) && Modifier.isStatic(modifiers)) {
-					try {
-						int captionId = field.getInt(resourceClass);
-						captionsByLanguage.put(field.getName(), context.getString(captionId));
-					} catch (IllegalAccessException e) {
-						Log.e(ResourceCache.class.getName(), e.getMessage());
-					} catch (Resources.NotFoundException e) {
-						Log.e(ResourceCache.class.getName(), "Caption with name " + field.getName() + " was not found for " + locale.getLanguage() + " language: " + e.getMessage());
+			final Locale defaultLocale = Locale.getDefault();
+
+			try {
+				if (!defaultLocale.getLanguage().equals(locale.getLanguage())) {
+					updateConfiguration(context, locale);
+				}
+
+				for (Field field : resourceClass.getDeclaredFields()) {
+					int modifiers = field.getModifiers();
+					if (Modifier.isFinal(modifiers) && Modifier.isStatic(modifiers)) {
+						try {
+							int captionId = field.getInt(resourceClass);
+							captionsByLanguage.put(field.getName(), context.getString(captionId));
+						} catch (IllegalAccessException e) {
+							Log.e(ResourceCache.class.getName(), e.getMessage());
+						} catch (Resources.NotFoundException e) {
+							Log.e(ResourceCache.class.getName(), "Caption with name " + field.getName() + " was not found for " + locale.getLanguage() + " language: " + e.getMessage());
+						}
 					}
 				}
+			} finally {
+				if (!defaultLocale.getLanguage().equals(locale.getLanguage())) {
+					updateConfiguration(context, defaultLocale);
+				}
 			}
 
 			captions.put(locale.getLanguage(), captionsByLanguage);
 		}
 	}
 
+	private static void updateConfiguration(@NotNull Context context, @NotNull Locale locale) {
+		Locale.setDefault(locale);
+		final Configuration config = new Configuration();
+		config.locale = locale;
+		context.getResources().updateConfiguration(config, context.getResources().getDisplayMetrics());
+	}
+
 	private boolean initialized(@NotNull Locale locale) {
 		return captions.containsKey(locale.getLanguage());
 	}
diff --git a/src/test/java/org/solovyev/android/calculator/model/CalculatorEngineTest.java b/src/test/java/org/solovyev/android/calculator/model/CalculatorEngineTest.java
index 99a1aa06..25d0b01f 100644
--- a/src/test/java/org/solovyev/android/calculator/model/CalculatorEngineTest.java
+++ b/src/test/java/org/solovyev/android/calculator/model/CalculatorEngineTest.java
@@ -416,7 +416,7 @@ public class CalculatorEngineTest {
 		Assert.assertEquals("∞", Expression.valueOf("ln(10)/ln(1)").numeric().toString());
 
 		// logarithm
-		Assert.assertEquals("ln(b)/ln(a)", ((CustomFunction) cm.getFunctionsRegistry().get("log")).getContent());
+		Assert.assertEquals("ln(x)/ln(base)", ((CustomFunction) cm.getFunctionsRegistry().get("log")).getContent());
 		Assert.assertEquals("∞", cm.evaluate(JsclOperation.numeric, "log(1, 10)").getResult());
 		Assert.assertEquals("3.322", cm.evaluate(JsclOperation.numeric, "log(2, 10)").getResult());
 		Assert.assertEquals("1.431", cm.evaluate(JsclOperation.numeric, "log(5, 10)").getResult());