From ef11120244fd2389c1637278f9009b6b4167d462 Mon Sep 17 00:00:00 2001
From: Sergey Solovyev <se.solovyev@gmail.com>
Date: Sat, 17 Nov 2012 23:53:56 +0400
Subject: [PATCH] Calculation fixable messages

---
 .../calculator/CalculatorFixableError.java    | 14 +++
 .../android/calculator/CalculatorImpl.java    |  2 +
 .../CalculatorPreferenceService.java          |  7 ++
 ...log.xml => calculator_messages_dialog.xml} |  0
 ...=> calculator_messages_dialog_message.xml} |  4 +-
 calculatorpp/res/values/text_strings.xml      |  8 ++
 .../res/xml/calculations_preferences.xml      | 14 +++
 .../AndroidCalculatorPreferenceService.java   | 61 ++++++++++++
 .../CalculatorActivityLauncher.java           |  2 +-
 .../calculator/CalculatorApplication.java     |  2 +
 .../android/calculator/CalculatorButtons.java |  6 +-
 ...age.java => CalculatorFixableMessage.java} | 24 ++---
 .../calculator/CalculatorMessagesDialog.java  | 94 ++++++++++++-------
 .../calculator/CalculatorPreferences.java     | 13 ++-
 14 files changed, 192 insertions(+), 59 deletions(-)
 rename calculatorpp/res/layout/{calculation_messages_dialog.xml => calculator_messages_dialog.xml} (100%)
 rename calculatorpp/res/layout/{calculation_messages_dialog_message.xml => calculator_messages_dialog_message.xml} (83%)
 rename calculatorpp/src/main/java/org/solovyev/android/calculator/{CalculationMessage.java => CalculatorFixableMessage.java} (66%)

diff --git a/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorFixableError.java b/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorFixableError.java
index 6ba533d6..5d898311 100644
--- a/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorFixableError.java
+++ b/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorFixableError.java
@@ -20,6 +20,20 @@ public enum CalculatorFixableError {
         public void fix() {
             CalculatorLocatorImpl.getInstance().getPreferenceService().setAngleUnits(AngleUnit.rad);
         }
+    },
+
+    preferred_numeral_base() {
+        @Override
+        public void fix() {
+            CalculatorLocatorImpl.getInstance().getPreferenceService().setPreferredNumeralBase();
+        }
+    },
+
+    preferred_angle_units() {
+        @Override
+        public void fix() {
+            CalculatorLocatorImpl.getInstance().getPreferenceService().setPreferredAngleUnits();
+        }
     };
 
     @NotNull
diff --git a/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorImpl.java b/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorImpl.java
index 3f1a6c2a..191a471a 100644
--- a/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorImpl.java
+++ b/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorImpl.java
@@ -163,6 +163,8 @@ public class CalculatorImpl implements Calculator, CalculatorEventListener {
                           @NotNull String expression,
                           @Nullable MessageRegistry mr) {
 
+        CalculatorLocatorImpl.getInstance().getPreferenceService().checkPreferredPreferences(false);
+
         PreparedExpression preparedExpression = null;
 
         try {
diff --git a/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorPreferenceService.java b/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorPreferenceService.java
index ca6a5d70..0d012015 100644
--- a/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorPreferenceService.java
+++ b/calculatorpp-core/src/main/java/org/solovyev/android/calculator/CalculatorPreferenceService.java
@@ -1,6 +1,7 @@
 package org.solovyev.android.calculator;
 
 import jscl.AngleUnit;
+import jscl.NumeralBase;
 import org.jetbrains.annotations.NotNull;
 
 /**
@@ -10,5 +11,11 @@ import org.jetbrains.annotations.NotNull;
  */
 public interface CalculatorPreferenceService {
 
+    void setPreferredAngleUnits();
     void setAngleUnits(@NotNull AngleUnit angleUnit);
+
+    void setPreferredNumeralBase();
+    void setNumeralBase(@NotNull NumeralBase numeralBase);
+
+    void checkPreferredPreferences(boolean force);
 }
diff --git a/calculatorpp/res/layout/calculation_messages_dialog.xml b/calculatorpp/res/layout/calculator_messages_dialog.xml
similarity index 100%
rename from calculatorpp/res/layout/calculation_messages_dialog.xml
rename to calculatorpp/res/layout/calculator_messages_dialog.xml
diff --git a/calculatorpp/res/layout/calculation_messages_dialog_message.xml b/calculatorpp/res/layout/calculator_messages_dialog_message.xml
similarity index 83%
rename from calculatorpp/res/layout/calculation_messages_dialog_message.xml
rename to calculatorpp/res/layout/calculator_messages_dialog_message.xml
index 65dd3e3b..ce34cfcd 100644
--- a/calculatorpp/res/layout/calculation_messages_dialog_message.xml
+++ b/calculatorpp/res/layout/calculator_messages_dialog_message.xml
@@ -8,13 +8,15 @@
     <TextView a:id="@+id/calculation_messages_text_view"
         a:layout_width="0dp"
         a:layout_height="wrap_content"
-        a:layout_weight="5"/>
+        a:layout_weight="5"
+        a:layout_gravity="top|left"/>
 
     <Button
         a:id="@+id/fix_button"
         a:layout_width="0dp"
         a:layout_height="wrap_content"
         a:layout_weight="1"
+        a:layout_gravity="top|right"
         a:text="@string/fix" />
 
 </LinearLayout>
\ No newline at end of file
diff --git a/calculatorpp/res/values/text_strings.xml b/calculatorpp/res/values/text_strings.xml
index c1c191a0..fe0a547b 100644
--- a/calculatorpp/res/values/text_strings.xml
+++ b/calculatorpp/res/values/text_strings.xml
@@ -257,4 +257,12 @@
     </string>
     <string name="fix">Fix</string>
 
+    <string name="p_preferred_numeral_base_title">Preferred numeral base</string>
+    <string name="p_preferred_numeral_base_summary">Defines the preferred numeral base</string>
+    <string name="preferred_numeral_base_message">Preferred numeral base \'%1$s\' differs from current numeral base \'%2$s\'. Forgot to change back?</string>
+
+    <string name="p_preferred_angle_units_title">Preferred angle units</string>
+    <string name="p_preferred_angle_units_summary">Defines the preferred angle units</string>
+    <string name="preferred_angle_units_message">Preferred angle units \'%1$s\' differs from current angle units \'%2$s\'. Forgot to change back?</string>
+
 </resources>
\ No newline at end of file
diff --git a/calculatorpp/res/xml/calculations_preferences.xml b/calculatorpp/res/xml/calculations_preferences.xml
index 0c71b68f..bd9e0d28 100644
--- a/calculatorpp/res/xml/calculations_preferences.xml
+++ b/calculatorpp/res/xml/calculations_preferences.xml
@@ -32,12 +32,26 @@
                         a:summary="@string/c_calc_grouping_separator_summary"
                         a:entryValues="@array/p_grouping_separator_values"/>
 
+        <ListPreference
+            a:key="preferred_angle_units"
+            a:title="@string/p_preferred_angle_units_title"
+            a:summary="@string/p_preferred_angle_units_summary"
+            a:entries="@array/p_angle_units_names"
+            a:entryValues="@array/p_angle_units" />
+
         <ListPreference a:key="@string/p_calc_angle_units_key"
                         a:title="@string/c_calc_angle_units"
                         a:entries="@array/p_angle_units_names"
                         a:summary="@string/c_angle_units_summary"
                         a:entryValues="@array/p_angle_units"/>
 
+        <ListPreference
+            a:key="preferred_numeral_base"
+            a:title="@string/p_preferred_numeral_base_title"
+            a:summary="@string/p_preferred_numeral_base_summary"
+            a:entries="@array/p_numeral_bases_names"
+            a:entryValues="@array/p_numeral_bases" />
+
         <ListPreference a:key="@string/p_calc_numeral_bases_key"
                         a:title="@string/c_calc_numeral_bases"
                         a:entries="@array/p_numeral_bases_names"
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/AndroidCalculatorPreferenceService.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/AndroidCalculatorPreferenceService.java
index 0a3cc7a3..4b2ec210 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/AndroidCalculatorPreferenceService.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/AndroidCalculatorPreferenceService.java
@@ -4,11 +4,15 @@ import android.app.Application;
 import android.content.SharedPreferences;
 import android.preference.PreferenceManager;
 import jscl.AngleUnit;
+import jscl.NumeralBase;
 import org.jetbrains.annotations.NotNull;
 import org.solovyev.android.calculator.model.AndroidCalculatorEngine;
 import org.solovyev.android.msg.AndroidMessage;
 import org.solovyev.common.msg.MessageType;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * User: serso
  * Date: 11/17/12
@@ -16,6 +20,9 @@ import org.solovyev.common.msg.MessageType;
  */
 public class AndroidCalculatorPreferenceService implements CalculatorPreferenceService {
 
+    // ont hour
+    private static final Long PREFERRED_PREFS_INTERVAL_TIME = 1000L * 60L * 60L;
+
     @NotNull
     private final Application application;
 
@@ -23,6 +30,46 @@ public class AndroidCalculatorPreferenceService implements CalculatorPreferenceS
         this.application = application;
     }
 
+    @Override
+    public void checkPreferredPreferences(boolean force) {
+        final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(application);
+
+        final Long currentTime = System.currentTimeMillis();
+
+        if ( force || isTimeForCheck(currentTime, preferences)) {
+            final NumeralBase preferredNumeralBase = CalculatorPreferences.Calculations.preferredNumeralBase.getPreference(preferences);
+            final NumeralBase numeralBase = AndroidCalculatorEngine.Preferences.numeralBase.getPreference(preferences);
+
+            final AngleUnit preferredAngleUnits = CalculatorPreferences.Calculations.preferredAngleUnits.getPreference(preferences);
+            final AngleUnit angleUnits = AndroidCalculatorEngine.Preferences.angleUnit.getPreference(preferences);
+
+            final List<CalculatorFixableMessage> messages = new ArrayList<CalculatorFixableMessage>(2);
+            if ( numeralBase != preferredNumeralBase ) {
+                messages.add(new CalculatorFixableMessage(application.getString(R.string.preferred_numeral_base_message, preferredNumeralBase.name(), numeralBase.name()), MessageType.warning, CalculatorFixableError.preferred_numeral_base));
+            }
+
+            if ( angleUnits != preferredAngleUnits ) {
+                messages.add(new CalculatorFixableMessage(application.getString(R.string.preferred_angle_units_message, preferredAngleUnits.name(), angleUnits.name()), MessageType.warning, CalculatorFixableError.preferred_angle_units));
+            }
+
+            CalculatorMessagesDialog.showDialog(messages, application);
+
+            CalculatorPreferences.Calculations.lastPreferredPreferencesCheck.putPreference(preferences, currentTime);
+        }
+    }
+
+    private boolean isTimeForCheck(@NotNull Long currentTime, @NotNull SharedPreferences preferences) {
+        final Long lastPreferredPreferencesCheckTime = CalculatorPreferences.Calculations.lastPreferredPreferencesCheck.getPreference(preferences);
+
+        return currentTime - lastPreferredPreferencesCheckTime > PREFERRED_PREFS_INTERVAL_TIME;
+    }
+
+    @Override
+    public void setPreferredAngleUnits() {
+        final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(application);
+        setAngleUnits(CalculatorPreferences.Calculations.preferredAngleUnits.getPreference(preferences));
+    }
+
     @Override
     public void setAngleUnits(@NotNull AngleUnit angleUnit) {
         final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(application);
@@ -30,4 +77,18 @@ public class AndroidCalculatorPreferenceService implements CalculatorPreferenceS
 
         CalculatorLocatorImpl.getInstance().getNotifier().showMessage(new AndroidMessage(R.string.c_angle_units_changed_to, MessageType.info, application, angleUnit.name()));
     }
+
+    @Override
+    public void setPreferredNumeralBase() {
+        final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(application);
+        setNumeralBase(CalculatorPreferences.Calculations.preferredNumeralBase.getPreference(preferences));
+    }
+
+    @Override
+    public void setNumeralBase(@NotNull NumeralBase numeralBase) {
+        final SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(application);
+        AndroidCalculatorEngine.Preferences.numeralBase.putPreference(preferences, numeralBase);
+
+        CalculatorLocatorImpl.getInstance().getNotifier().showMessage(new AndroidMessage(R.string.c_numeral_base_changed_to, MessageType.info, application, numeralBase.name()));
+    }
 }
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java
index 4446e926..c9d843ad 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java
@@ -163,7 +163,7 @@ public class CalculatorActivityLauncher {
         final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
 
         if ( CalculatorPreferences.Calculations.showCalculationMessagesDialog.getPreference(prefs) ) {
-            CalculatorMessagesDialog.showDialog(messages, context);
+            CalculatorMessagesDialog.showDialogForMessages(messages, context);
         }
     }
 }
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorApplication.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorApplication.java
index fb0ce759..86f6b121 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorApplication.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorApplication.java
@@ -126,6 +126,8 @@ public class CalculatorApplication extends android.app.Application {
 
         CalculatorLocatorImpl.getInstance().getLogger().debug(TAG, "Application started!");
         CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Application started!");
+
+        CalculatorLocatorImpl.getInstance().getPreferenceService().checkPreferredPreferences(true);
     }
 
     private void setTheme(@NotNull SharedPreferences preferences) {
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorButtons.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorButtons.java
index f499f456..b401210a 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorButtons.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorButtons.java
@@ -10,7 +10,6 @@ import android.view.MotionEvent;
 import android.view.View;
 import android.widget.Button;
 import android.widget.RemoteViews;
-import android.widget.Toast;
 import jscl.AngleUnit;
 import jscl.NumeralBase;
 import org.jetbrains.annotations.NotNull;
@@ -19,7 +18,6 @@ import org.solovyev.android.AndroidUtils;
 import org.solovyev.android.calculator.model.AndroidCalculatorEngine;
 import org.solovyev.android.calculator.view.AngleUnitsButton;
 import org.solovyev.android.calculator.view.NumeralBasesButton;
-import org.solovyev.android.view.drag.DirectionDragButton;
 import org.solovyev.android.view.drag.DragButton;
 import org.solovyev.android.view.drag.DragDirection;
 import org.solovyev.android.view.drag.SimpleOnDragListener;
@@ -217,9 +215,7 @@ public final class CalculatorButtons {
 
                         final NumeralBase oldNumeralBase = AndroidCalculatorEngine.Preferences.numeralBase.getPreference(preferences);
                         if (oldNumeralBase != numeralBase) {
-                            AndroidCalculatorEngine.Preferences.numeralBase.putPreference(preferences, numeralBase);
-
-                            Toast.makeText(context, context.getString(R.string.c_numeral_base_changed_to, numeralBase.name()), Toast.LENGTH_LONG).show();
+                            CalculatorLocatorImpl.getInstance().getPreferenceService().setNumeralBase(numeralBase);
                         }
 
                         result = true;
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculationMessage.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorFixableMessage.java
similarity index 66%
rename from calculatorpp/src/main/java/org/solovyev/android/calculator/CalculationMessage.java
rename to calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorFixableMessage.java
index 0660a480..8d6110e7 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculationMessage.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorFixableMessage.java
@@ -12,27 +12,27 @@ import org.solovyev.common.msg.MessageType;
  * Date: 11/17/12
  * Time: 6:54 PM
  */
-public class CalculationMessage implements Parcelable {
+public class CalculatorFixableMessage implements Parcelable {
 
-    public static final Creator<CalculationMessage> CREATOR = new Creator<CalculationMessage>() {
+    public static final Creator<CalculatorFixableMessage> CREATOR = new Creator<CalculatorFixableMessage>() {
         @Override
-        public CalculationMessage createFromParcel(@NotNull Parcel in) {
-            return CalculationMessage.fromParcel(in);
+        public CalculatorFixableMessage createFromParcel(@NotNull Parcel in) {
+            return CalculatorFixableMessage.fromParcel(in);
         }
 
         @Override
-        public CalculationMessage[] newArray(int size) {
-            return new CalculationMessage[size];
+        public CalculatorFixableMessage[] newArray(int size) {
+            return new CalculatorFixableMessage[size];
         }
     };
 
     @NotNull
-    private static CalculationMessage fromParcel(@NotNull Parcel in) {
+    private static CalculatorFixableMessage fromParcel(@NotNull Parcel in) {
         final String message = in.readString();
         final MessageType messageType = (MessageType) in.readSerializable();
         final CalculatorFixableError fixableError = (CalculatorFixableError) in.readSerializable();
 
-        return new CalculationMessage(message, messageType, fixableError);
+        return new CalculatorFixableMessage(message, messageType, fixableError);
     }
 
     @NotNull
@@ -44,15 +44,15 @@ public class CalculationMessage implements Parcelable {
     @Nullable
     private final CalculatorFixableError fixableError;
 
-    public CalculationMessage(@NotNull Message message) {
+    public CalculatorFixableMessage(@NotNull Message message) {
         this.message = message.getLocalizedMessage();
         this.messageType = message.getMessageType();
         this.fixableError = CalculatorFixableError.getErrorByMessageCode(message.getMessageCode());
     }
 
-    public CalculationMessage(@NotNull String message,
-                              @NotNull MessageType messageType,
-                              @Nullable CalculatorFixableError fixableError) {
+    public CalculatorFixableMessage(@NotNull String message,
+                                    @NotNull MessageType messageType,
+                                    @Nullable CalculatorFixableError fixableError) {
         this.message = message;
         this.messageType = messageType;
         this.fixableError = fixableError;
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorMessagesDialog.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorMessagesDialog.java
index 2ef1966a..88f5ea01 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorMessagesDialog.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorMessagesDialog.java
@@ -31,7 +31,7 @@ public class CalculatorMessagesDialog extends SherlockActivity {
     private static final String INPUT = "input";
 
     @NotNull
-    private Input input = new Input(Collections.<CalculationMessage>emptyList());
+    private Input input = new Input(Collections.<CalculatorFixableMessage>emptyList());
 
     public CalculatorMessagesDialog() {
     }
@@ -40,7 +40,7 @@ public class CalculatorMessagesDialog extends SherlockActivity {
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
-        setContentView(R.layout.calculation_messages_dialog);
+        setContentView(R.layout.calculator_messages_dialog);
 
         final Intent intent = getIntent();
         if (intent != null) {
@@ -77,9 +77,9 @@ public class CalculatorMessagesDialog extends SherlockActivity {
 
         final LayoutInflater layoutInflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
 
-        final List<CalculationMessage> messages = input.getMessages();
-        for (final CalculationMessage message : messages) {
-            final View view = layoutInflater.inflate(R.layout.calculation_messages_dialog_message, null);
+        final List<CalculatorFixableMessage> messages = input.getMessages();
+        for (final CalculatorFixableMessage message : messages) {
+            final View view = layoutInflater.inflate(R.layout.calculator_messages_dialog_message, null);
 
             final TextView calculationMessagesTextView = (TextView) view.findViewById(R.id.calculation_messages_text_view);
             calculationMessagesTextView.setText(message.getMessage());
@@ -91,26 +91,7 @@ public class CalculatorMessagesDialog extends SherlockActivity {
                 fixButton.setOnClickListener(null);
             } else {
                 fixButton.setVisibility(View.VISIBLE);
-                fixButton.setOnClickListener(new View.OnClickListener() {
-                    @Override
-                    public void onClick(View v) {
-                        final List<CalculationMessage> filteredMessages = new ArrayList<CalculationMessage>(messages.size() - 1);
-                        for (CalculationMessage calculationMessage : messages) {
-                            if ( calculationMessage.getFixableError() == null || calculationMessage.getFixableError() != message.getFixableError() ) {
-                                filteredMessages.add(message);
-                            }
-                        }
-
-                        fixableError.fix();
-
-                        if (!filteredMessages.isEmpty()) {
-                            CalculatorMessagesDialog.this.input = new Input(filteredMessages);
-                            onInputChanged();
-                        } else {
-                            CalculatorMessagesDialog.this.finish();
-                        }
-                    }
-                });
+                fixButton.setOnClickListener(new FixErrorOnClickListener(messages, message));
             }
 
             viewGroup.addView(view, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
@@ -132,7 +113,7 @@ public class CalculatorMessagesDialog extends SherlockActivity {
     **********************************************************************
     */
 
-    public static void showDialog(@NotNull List<Message> messages, @NotNull Context context) {
+    public static void showDialogForMessages(@NotNull List<Message> messages, @NotNull Context context) {
         if (!messages.isEmpty()) {
             final Intent intent = new Intent(context, CalculatorMessagesDialog.class);
 
@@ -143,6 +124,17 @@ public class CalculatorMessagesDialog extends SherlockActivity {
         }
     }
 
+    public static void showDialog(@NotNull List<CalculatorFixableMessage> messages, @NotNull Context context) {
+        if (!messages.isEmpty()) {
+            final Intent intent = new Intent(context, CalculatorMessagesDialog.class);
+
+            intent.putExtra(INPUT, new Input(messages));
+            intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+
+            context.startActivity(intent);
+        }
+    }
+
     private static final class Input implements Parcelable {
 
         public static final Creator<Input> CREATOR = new Creator<Input>() {
@@ -159,21 +151,21 @@ public class CalculatorMessagesDialog extends SherlockActivity {
 
         @NotNull
         private static Input fromParcel(@NotNull Parcel in) {
-            final List<CalculationMessage> messages = new ArrayList<CalculationMessage>();
-            in.readTypedList(messages, CalculationMessage.CREATOR);
+            final List<CalculatorFixableMessage> messages = new ArrayList<CalculatorFixableMessage>();
+            in.readTypedList(messages, CalculatorFixableMessage.CREATOR);
             return new Input(messages);
         }
 
 
         @NotNull
-        private List<CalculationMessage> messages = new ArrayList<CalculationMessage>();
+        private List<CalculatorFixableMessage> messages = new ArrayList<CalculatorFixableMessage>();
 
-        private Input(@NotNull List<CalculationMessage> messages) {
+        private Input(@NotNull List<CalculatorFixableMessage> messages) {
             this.messages = messages;
         }
 
         @NotNull
-        public List<CalculationMessage> getMessages() {
+        public List<CalculatorFixableMessage> getMessages() {
             return messages;
         }
 
@@ -189,13 +181,49 @@ public class CalculatorMessagesDialog extends SherlockActivity {
 
         @NotNull
         public static Input fromMessages(@NotNull List<Message> messages) {
-            final List<CalculationMessage> stringMessages = new ArrayList<CalculationMessage>(messages.size());
+            final List<CalculatorFixableMessage> stringMessages = new ArrayList<CalculatorFixableMessage>(messages.size());
             for (Message message : messages) {
-                stringMessages.add(new CalculationMessage(message));
+                stringMessages.add(new CalculatorFixableMessage(message));
             }
 
             return new Input(stringMessages);
         }
     }
+
+    private class FixErrorOnClickListener implements View.OnClickListener {
+
+        @NotNull
+        private final List<CalculatorFixableMessage> messages;
+
+        @NotNull
+        private final CalculatorFixableMessage currentMessage;
+
+        public FixErrorOnClickListener(@NotNull List<CalculatorFixableMessage> messages,
+                                       @NotNull CalculatorFixableMessage message) {
+            this.messages = messages;
+            this.currentMessage = message;
+        }
+
+        @Override
+        public void onClick(View v) {
+            final List<CalculatorFixableMessage> filteredMessages = new ArrayList<CalculatorFixableMessage>(messages.size() - 1);
+            for (CalculatorFixableMessage message : messages) {
+                if ( message.getFixableError() == null ) {
+                    filteredMessages.add(message);
+                } else if ( message.getFixableError() != currentMessage.getFixableError() ) {
+                    filteredMessages.add(message);
+                }
+            }
+
+            currentMessage.getFixableError().fix();
+
+            if (!filteredMessages.isEmpty()) {
+                CalculatorMessagesDialog.this.input = new Input(filteredMessages);
+                onInputChanged();
+            } else {
+                CalculatorMessagesDialog.this.finish();
+            }
+        }
+    }
 }
 
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorPreferences.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorPreferences.java
index 720a3d0c..2c75846c 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorPreferences.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorPreferences.java
@@ -8,10 +8,7 @@ import org.solovyev.android.AndroidUtils;
 import org.solovyev.android.calculator.math.MathType;
 import org.solovyev.android.calculator.model.AndroidCalculatorEngine;
 import org.solovyev.android.calculator.plot.GraphLineColor;
-import org.solovyev.android.prefs.BooleanPreference;
-import org.solovyev.android.prefs.IntegerPreference;
-import org.solovyev.android.prefs.Preference;
-import org.solovyev.android.prefs.StringPreference;
+import org.solovyev.android.prefs.*;
 import org.solovyev.android.view.VibratorContainer;
 
 import java.text.DecimalFormatSymbols;
@@ -36,8 +33,9 @@ public final class CalculatorPreferences {
         public static final Preference<Boolean> calculateOnFly = new BooleanPreference("calculations_calculate_on_fly", true);
         public static final Preference<Boolean> showCalculationMessagesDialog = new BooleanPreference("show_calculation_messages_dialog", true);
 
-        public static final Preference<NumeralBase> preferredNumeralBase = StringPreference.newInstance("preferred_numeral_base", NumeralBase.dec, NumeralBase.class);
-        public static final Preference<AngleUnit> preferredAngleUnit = StringPreference.newInstance("preferred_angle_units", AngleUnit.deg, AngleUnit.class);
+        public static final Preference<NumeralBase> preferredNumeralBase = StringPreference.newInstance("preferred_numeral_base", AndroidCalculatorEngine.Preferences.numeralBase.getDefaultValue(), NumeralBase.class);
+        public static final Preference<AngleUnit> preferredAngleUnits = StringPreference.newInstance("preferred_angle_units", AndroidCalculatorEngine.Preferences.angleUnit.getDefaultValue(), AngleUnit.class);
+        public static final Preference<Long> lastPreferredPreferencesCheck = new LongPreference("preferred_preferences_check_time", 0L);
 
     }
 
@@ -183,8 +181,9 @@ public final class CalculatorPreferences {
         applyDefaultPreference(preferences, Graph.lineColorReal);
         applyDefaultPreference(preferences, History.showIntermediateCalculations);
         applyDefaultPreference(preferences, Calculations.calculateOnFly);
-        applyDefaultPreference(preferences, Calculations.preferredAngleUnit);
+        applyDefaultPreference(preferences, Calculations.preferredAngleUnits);
         applyDefaultPreference(preferences, Calculations.preferredNumeralBase);
+        applyDefaultPreference(preferences, Calculations.lastPreferredPreferencesCheck);
 
 
         // renew value after each application start