From 422fd8f693a78f71df9742e1b0eafaa327047c7c Mon Sep 17 00:00:00 2001
From: Sergey Solovyev <se.solovyev@gmail.com>
Date: Sun, 25 Dec 2011 13:17:08 +0400
Subject: [PATCH] back button behaviour

---
 res/values-ru/text_strings.xml                   |  3 +++
 res/values/default_values.xml                    |  3 +++
 res/values/text_strings.xml                      |  3 +++
 res/xml/main_preferences.xml                     |  6 ++++++
 .../android/calculator/CalculatorActivity.java   | 16 ++++++++++++++--
 5 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/res/values-ru/text_strings.xml b/res/values-ru/text_strings.xml
index beef20c1..13440b6d 100644
--- a/res/values-ru/text_strings.xml
+++ b/res/values-ru/text_strings.xml
@@ -159,4 +159,7 @@
 	<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>
 
+	<string name="c_calc_use_back_button_as_prev_summary">Устанавливает поведение по нажатию на кнопку Назад</string>
+	<string name="c_calc_use_back_button_as_prev_title">Использовать кнопку назад как назад по истории</string>
+
 </resources>
\ No newline at end of file
diff --git a/res/values/default_values.xml b/res/values/default_values.xml
index 403d9b02..afb1d38c 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_use_back_button_as_prev_key">org.solovyev.android.calculator.CalculatorActivity_use_back_button_as_prev</string>
+	<string name="p_calc_use_back_button_as_prev">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>
 
diff --git a/res/values/text_strings.xml b/res/values/text_strings.xml
index 512d390c..cf9339ba 100644
--- a/res/values/text_strings.xml
+++ b/res/values/text_strings.xml
@@ -159,4 +159,7 @@
 	<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>
 
+	<string name="c_calc_use_back_button_as_prev_summary">Defines the behaviour of the Back button</string>
+	<string name="c_calc_use_back_button_as_prev_title">Use Back button as history prev</string>
+
 </resources>
\ No newline at end of file
diff --git a/res/xml/main_preferences.xml b/res/xml/main_preferences.xml
index 96d6e62a..c730f26f 100644
--- a/res/xml/main_preferences.xml
+++ b/res/xml/main_preferences.xml
@@ -92,6 +92,12 @@
 				a:title="@string/c_calc_show_release_notes_title"
 				a:defaultValue="true"/>
 
+		<android.preference.CheckBoxPreference
+				a:key="@string/p_calc_use_back_button_as_prev_key"
+				a:summary="@string/c_calc_use_back_button_as_prev_summary"
+				a:title="@string/c_calc_use_back_button_as_prev_title"
+				a:defaultValue="false"/>
+
 <!--	  <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 bd5799a7..8ddf54fa 100644
--- a/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
+++ b/src/main/java/org/solovyev/android/calculator/CalculatorActivity.java
@@ -56,6 +56,10 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 	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
+	public static final String USE_BACK_AS_PREV_P_KEY = "org.solovyev.android.calculator.CalculatorActivity_use_back_button_as_prev";
+	public static final boolean USE_BACK_AS_PREV_DEFAULT = false;
+
 	@NotNull
 	private final Announcer<DragPreferencesChangeListener> dpclRegister = new Announcer<DragPreferencesChangeListener>(DragPreferencesChangeListener.class);
 
@@ -73,6 +77,8 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 	@Nullable
 	private Vibrator vibrator;
 
+	private boolean useBackAsPrev = USE_BACK_AS_PREV_DEFAULT;
+
 	/**
 	 * Called when the activity is first created.
 	 */
@@ -510,8 +516,10 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 	@Override
 	public boolean onKeyDown(int keyCode, KeyEvent event) {
 		if (keyCode == KeyEvent.KEYCODE_BACK) {
-			calculatorModel.doHistoryAction(HistoryAction.undo);
-			return true;
+			if (useBackAsPrev) {
+				calculatorModel.doHistoryAction(HistoryAction.undo);
+				return true;
+			}
 		}
 		return super.onKeyDown(keyCode, event);
 	}
@@ -625,6 +633,10 @@ public class CalculatorActivity extends Activity implements FontSizeAdjuster, Sh
 			this.calculatorModel.evaluate();
 		}
 
+		if ( USE_BACK_AS_PREV_P_KEY.equals(key) ) {
+			useBackAsPrev = preferences.getBoolean(USE_BACK_AS_PREV_P_KEY, USE_BACK_AS_PREV_DEFAULT);
+		}
+
 		if ( CalculatorEngine.MULTIPLICATION_SIGN_P_KEY.equals(key) ) {
 			initMultiplicationButton();
 		}