diff --git a/calculatorpp/AndroidManifest.xml b/calculatorpp/AndroidManifest.xml
index ef5ac5c9..5e5e471a 100644
--- a/calculatorpp/AndroidManifest.xml
+++ b/calculatorpp/AndroidManifest.xml
@@ -6,6 +6,9 @@
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
     <uses-permission android:name="com.android.vending.BILLING"/>
 
+    <!-- for overlay -->
+    <uses-permission android:name="android.permission.SYSTEM_ALERT_WINDOW"/>
+
 
     <uses-sdk android:minSdkVersion="4" android:targetSdkVersion="8"/>
 
@@ -48,6 +51,22 @@
         <!-- settings must use action bar icon-->
         <activity android:icon="@drawable/ab_icon" android:label="@string/c_settings" android:name=".plot.CalculatorPlotPreferenceActivity"/>
 
+        <!-- OVERLAY CONFIG -->
+
+        <service android:name=".overlay.CalculatorOverlayService">
+            <intent-filter>
+                <action android:name="org.solovyev.calculator.widget.EDITOR_STATE_CHANGED"/>
+                <action android:name="org.solovyev.calculator.widget.DISPLAY_STATE_CHANGED"/>
+            </intent-filter>
+        </service>
+
+        <receiver android:name=".overlay.CalculatorOverlayBroadcastReceiver">
+            <intent-filter>
+                <action android:name="org.solovyev.calculator.widget.EDITOR_STATE_CHANGED"/>
+                <action android:name="org.solovyev.calculator.widget.DISPLAY_STATE_CHANGED"/>
+            </intent-filter>
+        </receiver>
+
         <!-- WIDGET CONFIG -->
 
         <receiver android:icon="@drawable/icon" android:label="@string/c_app_widget_3x3_name" android:name=".widget.CalculatorWidgetProvider">
diff --git a/calculatorpp/res/layout/overlay_layout.xml b/calculatorpp/res/layout/overlay_layout.xml
new file mode 100644
index 00000000..0d5bb932
--- /dev/null
+++ b/calculatorpp/res/layout/overlay_layout.xml
@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="utf-8"?>
+
+<LinearLayout xmlns:a="http://schemas.android.com/apk/res/android"
+              a:orientation="vertical"
+              style="@style/cpp_widget_main_layout_style">
+
+    <include layout="@layout/widget_editor"
+             a:layout_weight="2"
+             a:layout_width="match_parent"
+             a:layout_height="0dp"/>
+
+    <LinearLayout a:layout_weight="1"
+                  a:layout_width="match_parent"
+                  a:layout_height="0dp">
+
+        <include layout="@layout/widget_equals_button"
+                 a:layout_margin="@dimen/cpp_button_margin"
+                 a:layout_weight="1"
+                 a:layout_width="0dp"
+                 a:layout_height="match_parent"/>
+
+        <include layout="@layout/widget_display"
+                      a:layout_weight="5"
+                      a:layout_width="0dp"
+                      a:layout_height="wrap_content"/>
+
+    </LinearLayout>
+
+    <include layout="@layout/widget_keyboard"
+             a:layout_weight="5"
+             a:layout_width="match_parent"
+             a:layout_height="0dp"/>
+
+</LinearLayout>
\ No newline at end of file
diff --git a/calculatorpp/res/values/theme_gray.xml b/calculatorpp/res/values/theme_gray.xml
index 19c56f35..1ffb78ea 100644
--- a/calculatorpp/res/values/theme_gray.xml
+++ b/calculatorpp/res/values/theme_gray.xml
@@ -86,6 +86,11 @@
         <item name="android:layout_width">match_parent</item>
     </style>
 
+    <style name="cpp_overlay_main_layout_style" parent="cpp_default_main_layout_style">
+        <item name="android:layout_height">400dp</item>
+        <item name="android:layout_width">250dp</item>
+    </style>
+
     <style name="cpp_widget_main_layout_style" parent="cpp_default_main_layout_style">
         <item name="android:padding">1dp</item>
         <item name="android:layout_margin">@dimen/cpp_widget_margin</item>
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 aad0b963..98364902 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorApplication.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/CalculatorApplication.java
@@ -1,5 +1,6 @@
 package org.solovyev.android.calculator;
 
+import android.content.Intent;
 import android.content.SharedPreferences;
 import android.preference.PreferenceManager;
 import net.robotmedia.billing.BillingController;
@@ -12,6 +13,7 @@ import org.jetbrains.annotations.NotNull;
 import org.solovyev.android.ads.AdsController;
 import org.solovyev.android.calculator.history.AndroidCalculatorHistory;
 import org.solovyev.android.calculator.model.AndroidCalculatorEngine;
+import org.solovyev.android.calculator.overlay.CalculatorOverlayService;
 import org.solovyev.android.calculator.widget.CalculatorWidgetHelper;
 
 /**
@@ -100,6 +102,8 @@ public class CalculatorApplication extends android.app.Application {
         widgetHelper = new CalculatorWidgetHelper();
         CalculatorLocatorImpl.getInstance().getCalculator().addCalculatorEventListener(widgetHelper);
 
+        BillingDB.init(CalculatorApplication.this);
+
         AdsController.getInstance().init(ADMOB_USER_ID, AD_FREE_PRODUCT_ID, new BillingController.IConfiguration() {
 
             @Override
@@ -119,9 +123,10 @@ public class CalculatorApplication extends android.app.Application {
         new Thread(new Runnable() {
             @Override
             public void run() {
-                BillingDB.init(CalculatorApplication.this);
                 BillingController.checkBillingSupported(CalculatorApplication.this);
                 AdsController.getInstance().isAdFree(CalculatorApplication.this);
+
+                startService(new Intent(getApplicationContext(), CalculatorOverlayService.class));
             }
         }).start();
 
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/external/DefaultExternalCalculatorIntentHandler.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/external/DefaultExternalCalculatorIntentHandler.java
new file mode 100644
index 00000000..ecd1c90b
--- /dev/null
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/external/DefaultExternalCalculatorIntentHandler.java
@@ -0,0 +1,90 @@
+package org.solovyev.android.calculator.external;
+
+import android.content.Context;
+import android.content.Intent;
+import android.os.Parcelable;
+import org.jetbrains.annotations.NotNull;
+import org.solovyev.android.calculator.CalculatorDisplayViewState;
+import org.solovyev.android.calculator.CalculatorEditorViewState;
+import org.solovyev.android.calculator.CalculatorLocatorImpl;
+import org.solovyev.common.MutableObject;
+
+/**
+ * User: serso
+ * Date: 11/20/12
+ * Time: 10:34 PM
+ */
+public class DefaultExternalCalculatorIntentHandler implements ExternalCalculatorIntentHandler {
+
+    private static final String TAG = ExternalCalculatorIntentHandler.class.getSimpleName();
+
+    @NotNull
+    private final MutableObject<Long> lastDisplayEventId = new MutableObject<Long>(0L);
+
+    @NotNull
+    private final MutableObject<Long> lastEditorEventId = new MutableObject<Long>(0L);
+
+    @NotNull
+    private final ExternalCalculatorStateUpdater stateUpdater;
+
+    public DefaultExternalCalculatorIntentHandler(@NotNull ExternalCalculatorStateUpdater stateUpdater) {
+        this.stateUpdater = stateUpdater;
+    }
+
+    @Override
+    public void onIntent(@NotNull Context context, @NotNull Intent intent) {
+
+        if (ExternalCalculatorHelper.EDITOR_STATE_CHANGED_ACTION.equals(intent.getAction())) {
+            CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Editor state changed broadcast received!");
+
+            final Long eventId = intent.getLongExtra(ExternalCalculatorHelper.EVENT_ID_EXTRA, 0L);
+
+            boolean updateEditor = false;
+            synchronized (lastEditorEventId) {
+                if (eventId > lastEditorEventId.getObject()) {
+                    lastEditorEventId.setObject(eventId);
+                    updateEditor = true;
+                }
+            }
+
+            if (updateEditor) {
+                final Parcelable object = intent.getParcelableExtra(ExternalCalculatorHelper.EDITOR_STATE_EXTRA);
+                if (object instanceof CalculatorEditorViewState) {
+                    onEditorStateChanged(context, (CalculatorEditorViewState) object);
+                }
+            }
+        } else if (ExternalCalculatorHelper.DISPLAY_STATE_CHANGED_ACTION.equals(intent.getAction())) {
+            CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Display state changed broadcast received!");
+
+            final Long eventId = intent.getLongExtra(ExternalCalculatorHelper.EVENT_ID_EXTRA, 0L);
+            boolean updateDisplay = false;
+            synchronized (lastDisplayEventId) {
+                if (eventId > lastDisplayEventId.getObject()) {
+                    lastDisplayEventId.setObject(eventId);
+                    updateDisplay = true;
+                }
+            }
+
+            if (updateDisplay) {
+                final Parcelable object = intent.getParcelableExtra(ExternalCalculatorHelper.DISPLAY_STATE_EXTRA);
+                if (object instanceof CalculatorDisplayViewState) {
+                    onDisplayStateChanged(context, (CalculatorDisplayViewState) object);
+                }
+            }
+        }
+    }
+
+    protected void updateState(@NotNull Context context,
+                             @NotNull CalculatorEditorViewState editorViewState,
+                             @NotNull CalculatorDisplayViewState displayViewState) {
+        stateUpdater.updateState(context, editorViewState, displayViewState);
+    }
+
+    protected void onDisplayStateChanged(@NotNull Context context, @NotNull CalculatorDisplayViewState displayViewState) {
+        updateState(context, CalculatorLocatorImpl.getInstance().getEditor().getViewState(), displayViewState);
+    }
+
+    protected void onEditorStateChanged(@NotNull Context context, @NotNull CalculatorEditorViewState editorViewState) {
+        updateState(context, editorViewState, CalculatorLocatorImpl.getInstance().getDisplay().getViewState());
+    }
+}
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/external/ExternalCalculatorHelper.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/external/ExternalCalculatorHelper.java
new file mode 100644
index 00000000..5f0357d3
--- /dev/null
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/external/ExternalCalculatorHelper.java
@@ -0,0 +1,69 @@
+package org.solovyev.android.calculator.external;
+
+import android.content.Context;
+import android.content.Intent;
+import android.os.Parcelable;
+import org.jetbrains.annotations.NotNull;
+import org.solovyev.android.calculator.*;
+
+import java.util.HashSet;
+import java.util.Set;
+
+/**
+ * User: serso
+ * Date: 11/20/12
+ * Time: 10:14 PM
+ */
+public class ExternalCalculatorHelper {
+    /*
+        **********************************************************************
+        *
+        *                           CONSTANTS
+        *
+        **********************************************************************
+        */
+    public static final String EVENT_ID_EXTRA = "eventId";
+    public static final String EDITOR_STATE_CHANGED_ACTION = "org.solovyev.calculator.widget.EDITOR_STATE_CHANGED";
+    public static final String EDITOR_STATE_EXTRA = "editorState";
+    public static final String DISPLAY_STATE_CHANGED_ACTION = "org.solovyev.calculator.widget.DISPLAY_STATE_CHANGED";
+    public static final String DISPLAY_STATE_EXTRA = "displayState";
+
+    private static final String TAG = ExternalCalculatorHelper.class.getSimpleName();
+
+    private static final Set<Class<?>> externalListeners = new HashSet<Class<?>>();
+
+    public static void onEditorStateChanged(@NotNull Context context,
+                                            @NotNull CalculatorEventData calculatorEventData,
+                                            @NotNull CalculatorEditorViewState editorViewState) {
+
+        for (Class<?> externalListener : externalListeners) {
+            final Intent intent = new Intent(EDITOR_STATE_CHANGED_ACTION);
+            intent.setClass(context, externalListener);
+            intent.putExtra(EVENT_ID_EXTRA, calculatorEventData.getEventId());
+            intent.putExtra(EDITOR_STATE_EXTRA, (Parcelable) new ParcelableCalculatorEditorViewState(editorViewState));
+            context.sendBroadcast(intent);
+            CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Editor state changed broadcast sent");
+        }
+    }
+
+    public static void onDisplayStateChanged(@NotNull Context context,
+                                             @NotNull CalculatorEventData calculatorEventData,
+                                             @NotNull CalculatorDisplayViewState displayViewState) {
+        for (Class<?> externalListener : externalListeners) {
+            final Intent intent = new Intent(DISPLAY_STATE_CHANGED_ACTION);
+            intent.setClass(context, externalListener);
+            intent.putExtra(EVENT_ID_EXTRA, calculatorEventData.getEventId());
+            intent.putExtra(DISPLAY_STATE_EXTRA, (Parcelable) new ParcelableCalculatorDisplayViewState(displayViewState));
+            context.sendBroadcast(intent);
+            CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Display state changed broadcast sent");
+        }
+    }
+
+    public static void addExternalListener(@NotNull Class<?> externalCalculatorClass) {
+        externalListeners.add(externalCalculatorClass);
+    }
+
+    public static boolean removeExternalListener(@NotNull Class<?> externalCalculatorClass) {
+        return externalListeners.remove(externalCalculatorClass);
+    }
+}
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/external/ExternalCalculatorIntentHandler.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/external/ExternalCalculatorIntentHandler.java
new file mode 100644
index 00000000..9f539e7b
--- /dev/null
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/external/ExternalCalculatorIntentHandler.java
@@ -0,0 +1,15 @@
+package org.solovyev.android.calculator.external;
+
+import android.content.Context;
+import android.content.Intent;
+import org.jetbrains.annotations.NotNull;
+
+/**
+ * User: serso
+ * Date: 11/20/12
+ * Time: 10:33 PM
+ */
+public interface ExternalCalculatorIntentHandler {
+
+    void onIntent(@NotNull Context context, @NotNull Intent intent);
+}
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/external/ExternalCalculatorStateUpdater.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/external/ExternalCalculatorStateUpdater.java
new file mode 100644
index 00000000..d2e73b88
--- /dev/null
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/external/ExternalCalculatorStateUpdater.java
@@ -0,0 +1,18 @@
+package org.solovyev.android.calculator.external;
+
+import android.content.Context;
+import org.jetbrains.annotations.NotNull;
+import org.solovyev.android.calculator.CalculatorDisplayViewState;
+import org.solovyev.android.calculator.CalculatorEditorViewState;
+
+/**
+ * User: serso
+ * Date: 11/20/12
+ * Time: 10:42 PM
+ */
+public interface ExternalCalculatorStateUpdater {
+
+    void updateState(@NotNull Context context,
+                     @NotNull CalculatorEditorViewState editorState,
+                     @NotNull CalculatorDisplayViewState displayState);
+}
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/overlay/CalculatorOverlayBroadcastReceiver.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/overlay/CalculatorOverlayBroadcastReceiver.java
new file mode 100644
index 00000000..fa4f433f
--- /dev/null
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/overlay/CalculatorOverlayBroadcastReceiver.java
@@ -0,0 +1,25 @@
+package org.solovyev.android.calculator.overlay;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import org.jetbrains.annotations.NotNull;
+
+/**
+* User: serso
+* Date: 11/20/12
+* Time: 11:05 PM
+*/
+public final class CalculatorOverlayBroadcastReceiver extends BroadcastReceiver {
+
+    public CalculatorOverlayBroadcastReceiver() {
+    }
+
+    @Override
+    public void onReceive(@NotNull Context context,
+                          @NotNull Intent intent) {
+        final Intent newIntent = new Intent(intent);
+        newIntent.setClass(context, CalculatorOverlayService.class);
+        context.startService(newIntent);
+    }
+}
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/overlay/CalculatorOverlayService.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/overlay/CalculatorOverlayService.java
new file mode 100644
index 00000000..d859b2bc
--- /dev/null
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/overlay/CalculatorOverlayService.java
@@ -0,0 +1,163 @@
+package org.solovyev.android.calculator.overlay;
+
+import android.app.Service;
+import android.content.Context;
+import android.content.Intent;
+import android.graphics.PixelFormat;
+import android.os.IBinder;
+import android.text.Html;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.WindowManager;
+import android.widget.TextView;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+import org.solovyev.android.calculator.CalculatorDisplayViewState;
+import org.solovyev.android.calculator.CalculatorEditorViewState;
+import org.solovyev.android.calculator.R;
+import org.solovyev.android.calculator.external.DefaultExternalCalculatorIntentHandler;
+import org.solovyev.android.calculator.external.ExternalCalculatorHelper;
+import org.solovyev.android.calculator.external.ExternalCalculatorIntentHandler;
+import org.solovyev.android.calculator.external.ExternalCalculatorStateUpdater;
+import org.solovyev.android.calculator.widget.WidgetButton;
+
+/**
+ * User: serso
+ * Date: 11/20/12
+ * Time: 9:42 PM
+ */
+public class CalculatorOverlayService extends Service implements ExternalCalculatorStateUpdater {
+
+    @Nullable
+    private View view;
+
+    @NotNull
+    private final ExternalCalculatorIntentHandler intentHandler = new DefaultExternalCalculatorIntentHandler(this);
+
+    @Nullable
+    private static String cursorColor;
+
+    @Override
+    public IBinder onBind(Intent intent) {
+        return null;
+    }
+
+    @Override
+    public void onCreate() {
+        super.onCreate();
+
+        final LayoutInflater layoutInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
+        view = layoutInflater.inflate(R.layout.overlay_layout, null);
+
+        final WindowManager.LayoutParams params = new WindowManager.LayoutParams(
+                300,
+                450,
+                WindowManager.LayoutParams.TYPE_SYSTEM_ALERT,
+                WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE|WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL|WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH,
+                PixelFormat.TRANSLUCENT);
+
+        for (final WidgetButton widgetButton : WidgetButton.values()) {
+            final View button = view.findViewById(widgetButton.getButtonId());
+            if (button != null) {
+                button.setOnClickListener(new View.OnClickListener() {
+                    @Override
+                    public void onClick(View v) {
+                        widgetButton.onClick(CalculatorOverlayService.this);
+                    }
+                });
+            }
+        }
+
+        final WindowManager wm = (WindowManager) getSystemService(WINDOW_SERVICE);
+        wm.addView(view, params);
+
+        startCalculatorListening();
+    }
+
+    private void startCalculatorListening() {
+        ExternalCalculatorHelper.addExternalListener(getIntentListenerClass());
+    }
+
+    @NotNull
+    private Class<?> getIntentListenerClass() {
+        return CalculatorOverlayBroadcastReceiver.class;
+    }
+
+    private void stopCalculatorListening() {
+        ExternalCalculatorHelper.removeExternalListener(getIntentListenerClass());
+    }
+
+    @Override
+    public void onDestroy() {
+        stopCalculatorListening();
+
+        if (view != null) {
+            ((WindowManager) getSystemService(WINDOW_SERVICE)).removeView(view);
+            view = null;
+        }
+
+        super.onDestroy();
+    }
+
+    @Override
+    public void updateState(@NotNull Context context, @NotNull CalculatorEditorViewState editorState, @NotNull CalculatorDisplayViewState displayState) {
+        final View root = this.view;
+        if (root != null) {
+            updateDisplayState(context, root, displayState);
+            updateEditorState(context, root, editorState);
+        }
+    }
+
+    private static void updateDisplayState(@NotNull Context context, @NotNull View root, @NotNull CalculatorDisplayViewState displayState) {
+        final TextView calculatorDisplayView = (TextView) root.findViewById(R.id.calculator_display);
+        if (calculatorDisplayView != null) {
+            if (displayState.isValid()) {
+                calculatorDisplayView.setText(displayState.getText());
+                calculatorDisplayView.setTextColor(context.getResources().getColor(R.color.cpp_default_text_color));
+            } else {
+                calculatorDisplayView.setTextColor(context.getResources().getColor(R.color.cpp_display_error_text_color));
+            }
+        }
+    }
+
+    private static void updateEditorState(@NotNull Context context, @NotNull View root, @NotNull CalculatorEditorViewState editorState) {
+        final TextView calculatorEditorView = (TextView) root.findViewById(R.id.calculator_editor);
+
+        if (calculatorEditorView != null) {
+            String text = editorState.getText();
+
+            CharSequence newText = text;
+            int selection = editorState.getSelection();
+            if (selection >= 0 && selection <= text.length()) {
+                // inject cursor
+                newText = Html.fromHtml(text.substring(0, selection) + "<font color=\"#" + getCursorColor(context) + "\">|</font>" + text.substring(selection));
+            }
+            calculatorEditorView.setText(newText);
+        }
+    }
+
+    @NotNull
+    private static String getCursorColor(@NotNull Context context) {
+        if (cursorColor == null) {
+            cursorColor = Integer.toHexString(context.getResources().getColor(R.color.cpp_widget_cursor_color)).substring(2);
+        }
+        return cursorColor;
+    }
+
+    @Override
+    public void onStart(Intent intent, int startId) {
+        super.onStart(intent, startId);
+    }
+
+    @Override
+    public int onStartCommand(Intent intent, int flags, int startId) {
+        int result = super.onStartCommand(intent, flags, startId);
+
+        if ( intent != null ) {
+            intentHandler.onIntent(this, intent);
+        }
+
+        return result;
+    }
+}
+
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/AbstractCalculatorWidgetProvider.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/AbstractCalculatorWidgetProvider.java
index 316b65ef..d1f89d09 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/AbstractCalculatorWidgetProvider.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/AbstractCalculatorWidgetProvider.java
@@ -6,41 +6,24 @@ import android.appwidget.AppWidgetProvider;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
-import android.os.Parcelable;
 import android.text.Html;
 import android.widget.RemoteViews;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.calculator.*;
-import org.solovyev.common.MutableObject;
-
-import java.util.ArrayList;
-import java.util.List;
+import org.solovyev.android.calculator.external.ExternalCalculatorHelper;
+import org.solovyev.android.calculator.external.ExternalCalculatorIntentHandler;
+import org.solovyev.android.calculator.external.ExternalCalculatorStateUpdater;
 
 /**
  * User: Solovyev_S
  * Date: 19.10.12
  * Time: 16:18
  */
-abstract class AbstractCalculatorWidgetProvider extends AppWidgetProvider {
+abstract class AbstractCalculatorWidgetProvider extends AppWidgetProvider implements ExternalCalculatorStateUpdater {
 
-    /*
-    **********************************************************************
-    *
-    *                           CONSTANTS
-    *
-    **********************************************************************
-    */
-    private static final String EVENT_ID_EXTRA = "eventId";
-
-    private static final String BUTTON_ID_EXTRA = "buttonId";
-    private static final String BUTTON_PRESSED_ACTION = "org.solovyev.calculator.widget.BUTTON_PRESSED";
-
-    private static final String EDITOR_STATE_CHANGED_ACTION = "org.solovyev.calculator.widget.EDITOR_STATE_CHANGED";
-    private static final String EDITOR_STATE_EXTRA = "editorState";
-
-    private static final String DISPLAY_STATE_CHANGED_ACTION = "org.solovyev.calculator.widget.DISPLAY_STATE_CHANGED";
-    private static final String DISPLAY_STATE_EXTRA = "displayState";
+    static final String BUTTON_ID_EXTRA = "buttonId";
+    static final String BUTTON_PRESSED_ACTION = "org.solovyev.calculator.widget.BUTTON_PRESSED";
 
     private static final String TAG = "Calculator++ Widget";
 
@@ -56,10 +39,8 @@ abstract class AbstractCalculatorWidgetProvider extends AppWidgetProvider {
     private String cursorColor;
 
     @NotNull
-    private final MutableObject<Long> lastDisplayEventId = new MutableObject<Long>(0L);
+    private ExternalCalculatorIntentHandler intentHandler = new CalculatorWidgetIntentHandler(this);
 
-    @NotNull
-    private final MutableObject<Long> lastEditorEventId = new MutableObject<Long>(0L);
 
     /*
     **********************************************************************
@@ -71,9 +52,8 @@ abstract class AbstractCalculatorWidgetProvider extends AppWidgetProvider {
 
     protected AbstractCalculatorWidgetProvider() {
         final Class<? extends AppWidgetProvider> componentClass = this.getComponentClass();
-        if (!knownAppWidgetProviderClasses.contains(componentClass)) {
-            knownAppWidgetProviderClasses.add(componentClass);
-        }
+
+        ExternalCalculatorHelper.addExternalListener(componentClass);
     }
 
     /*
@@ -108,9 +88,10 @@ abstract class AbstractCalculatorWidgetProvider extends AppWidgetProvider {
         updateWidget(context, appWidgetManager, appWidgetIds, CalculatorLocatorImpl.getInstance().getEditor().getViewState(), CalculatorLocatorImpl.getInstance().getDisplay().getViewState());
     }
 
-    private void updateWidget(@NotNull Context context,
-                              @NotNull CalculatorEditorViewState editorState,
-                              @NotNull CalculatorDisplayViewState displayState) {
+    @Override
+    public void updateState(@NotNull Context context,
+                            @NotNull CalculatorEditorViewState editorState,
+                            @NotNull CalculatorDisplayViewState displayState) {
         final AppWidgetManager appWidgetManager = AppWidgetManager.getInstance(context);
         final int[] appWidgetIds = appWidgetManager.getAppWidgetIds(new ComponentName(context, getComponentClass()));
         updateWidget(context, appWidgetManager, appWidgetIds, editorState, displayState);
@@ -153,53 +134,7 @@ abstract class AbstractCalculatorWidgetProvider extends AppWidgetProvider {
     public void onReceive(Context context, Intent intent) {
         super.onReceive(context, intent);
 
-        if (AbstractCalculatorWidgetProvider.BUTTON_PRESSED_ACTION.equals(intent.getAction())) {
-            final int buttonId = intent.getIntExtra(AbstractCalculatorWidgetProvider.BUTTON_ID_EXTRA, 0);
-
-            final WidgetButton button = WidgetButton.getById(buttonId);
-            if (button != null) {
-                button.onClick(context);
-            }
-        } else if (EDITOR_STATE_CHANGED_ACTION.equals(intent.getAction())) {
-            CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Editor state changed broadcast received!");
-
-            final Long eventId = intent.getLongExtra(EVENT_ID_EXTRA, 0L);
-
-            boolean updateEditor = false;
-            synchronized (lastEditorEventId) {
-                if (eventId > lastEditorEventId.getObject()) {
-                    lastEditorEventId.setObject(eventId);
-                    updateEditor = true;
-                }
-            }
-
-            if (updateEditor) {
-                final Parcelable object = intent.getParcelableExtra(EDITOR_STATE_EXTRA);
-                if (object instanceof CalculatorEditorViewState) {
-                    updateWidget(context, (CalculatorEditorViewState) object, CalculatorLocatorImpl.getInstance().getDisplay().getViewState());
-                }
-            }
-        } else if (DISPLAY_STATE_CHANGED_ACTION.equals(intent.getAction())) {
-            CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Display state changed broadcast received!");
-
-            final Long eventId = intent.getLongExtra(EVENT_ID_EXTRA, 0L);
-            boolean updateDisplay = false;
-            synchronized (lastDisplayEventId) {
-                if (eventId > lastDisplayEventId.getObject()) {
-                    lastDisplayEventId.setObject(eventId);
-                    updateDisplay = true;
-                }
-            }
-
-            if (updateDisplay) {
-                final Parcelable object = intent.getParcelableExtra(DISPLAY_STATE_EXTRA);
-                if (object instanceof CalculatorDisplayViewState) {
-                    updateWidget(context, CalculatorLocatorImpl.getInstance().getEditor().getViewState(), (CalculatorDisplayViewState) object);
-                }
-            }
-        } else if (Intent.ACTION_CONFIGURATION_CHANGED.equals(intent.getAction())) {
-            updateWidget(context, CalculatorLocatorImpl.getInstance().getEditor().getViewState(), CalculatorLocatorImpl.getInstance().getDisplay().getViewState());
-        }
+        this.intentHandler.onIntent(context, intent);
     }
 
     private void updateDisplayState(@NotNull Context context, @NotNull RemoteViews views, @NotNull CalculatorDisplayViewState displayState) {
@@ -223,42 +158,4 @@ abstract class AbstractCalculatorWidgetProvider extends AppWidgetProvider {
         CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "New editor state: " + text);
         views.setTextViewText(R.id.calculator_editor, newText);
     }
-
-    /*
-    **********************************************************************
-    *
-    *                           STATIC
-    *
-    **********************************************************************
-    */
-
-    private static final List<Class<? extends AppWidgetProvider>> knownAppWidgetProviderClasses = new ArrayList<Class<? extends AppWidgetProvider>>();
-
-    public static void onEditorStateChanged(@NotNull Context context,
-                                            @NotNull CalculatorEventData calculatorEventData,
-                                            @NotNull CalculatorEditorViewState editorViewState) {
-
-        for (Class<? extends AppWidgetProvider> appWidgetProviderClass : knownAppWidgetProviderClasses) {
-            final Intent intent = new Intent(EDITOR_STATE_CHANGED_ACTION);
-            intent.setClass(context, appWidgetProviderClass);
-            intent.putExtra(EVENT_ID_EXTRA, calculatorEventData.getEventId());
-            intent.putExtra(EDITOR_STATE_EXTRA, (Parcelable) new ParcelableCalculatorEditorViewState(editorViewState));
-            context.sendBroadcast(intent);
-            CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Editor state changed broadcast sent");
-        }
-    }
-
-    public static void onDisplayStateChanged(@NotNull Context context,
-                                             @NotNull CalculatorEventData calculatorEventData,
-                                             @NotNull CalculatorDisplayViewState displayViewState) {
-        for (Class<? extends AppWidgetProvider> appWidgetProviderClass : knownAppWidgetProviderClasses) {
-            final Intent intent = new Intent(DISPLAY_STATE_CHANGED_ACTION);
-            intent.setClass(context, appWidgetProviderClass);
-            intent.putExtra(EVENT_ID_EXTRA, calculatorEventData.getEventId());
-            intent.putExtra(DISPLAY_STATE_EXTRA, (Parcelable)new ParcelableCalculatorDisplayViewState(displayViewState));
-            context.sendBroadcast(intent);
-            CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Display state changed broadcast sent");
-        }
-    }
-
 }
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/CalculatorWidgetHelper.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/CalculatorWidgetHelper.java
index 2a2428f9..b38b27f3 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/CalculatorWidgetHelper.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/CalculatorWidgetHelper.java
@@ -3,6 +3,7 @@ package org.solovyev.android.calculator.widget;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.solovyev.android.calculator.*;
+import org.solovyev.android.calculator.external.ExternalCalculatorHelper;
 
 /**
  * User: serso
@@ -32,7 +33,7 @@ public class CalculatorWidgetHelper implements CalculatorEventListener {
 
                     CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Editor state changed: " + newEditorState.getText());
 
-                    AbstractCalculatorWidgetProvider.onEditorStateChanged(CalculatorApplication.getInstance(), calculatorEventData, newEditorState);
+                    ExternalCalculatorHelper.onEditorStateChanged(CalculatorApplication.getInstance(), calculatorEventData, newEditorState);
                     break;
 
                 case display_state_changed:
@@ -41,7 +42,7 @@ public class CalculatorWidgetHelper implements CalculatorEventListener {
 
                     CalculatorLocatorImpl.getInstance().getNotifier().showDebugMessage(TAG, "Display state changed: " + newDisplayState.getText());
 
-                    AbstractCalculatorWidgetProvider.onDisplayStateChanged(CalculatorApplication.getInstance(), calculatorEventData, newDisplayState);
+                    ExternalCalculatorHelper.onDisplayStateChanged(CalculatorApplication.getInstance(), calculatorEventData, newDisplayState);
                     break;
             }
         }
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/CalculatorWidgetIntentHandler.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/CalculatorWidgetIntentHandler.java
new file mode 100644
index 00000000..1f166e4f
--- /dev/null
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/CalculatorWidgetIntentHandler.java
@@ -0,0 +1,37 @@
+package org.solovyev.android.calculator.widget;
+
+import android.content.Context;
+import android.content.Intent;
+import org.jetbrains.annotations.NotNull;
+import org.solovyev.android.calculator.CalculatorLocatorImpl;
+import org.solovyev.android.calculator.external.DefaultExternalCalculatorIntentHandler;
+import org.solovyev.android.calculator.external.ExternalCalculatorStateUpdater;
+
+/**
+ * User: serso
+ * Date: 11/20/12
+ * Time: 10:39 PM
+ */
+public class CalculatorWidgetIntentHandler extends DefaultExternalCalculatorIntentHandler {
+
+    public CalculatorWidgetIntentHandler(@NotNull ExternalCalculatorStateUpdater stateUpdater) {
+        super(stateUpdater);
+    }
+
+    @Override
+    public void onIntent(@NotNull Context context, @NotNull Intent intent) {
+        super.onIntent(context, intent);
+
+        if (AbstractCalculatorWidgetProvider.BUTTON_PRESSED_ACTION.equals(intent.getAction())) {
+            final int buttonId = intent.getIntExtra(AbstractCalculatorWidgetProvider.BUTTON_ID_EXTRA, 0);
+
+            final WidgetButton button = WidgetButton.getById(buttonId);
+            if (button != null) {
+                button.onClick(context);
+            }
+        } else if (Intent.ACTION_CONFIGURATION_CHANGED.equals(intent.getAction())) {
+            updateState(context, CalculatorLocatorImpl.getInstance().getEditor().getViewState(), CalculatorLocatorImpl.getInstance().getDisplay().getViewState());
+        }
+    }
+
+}
diff --git a/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/WidgetButton.java b/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/WidgetButton.java
index 94fab478..1ec7108d 100644
--- a/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/WidgetButton.java
+++ b/calculatorpp/src/main/java/org/solovyev/android/calculator/widget/WidgetButton.java
@@ -15,7 +15,7 @@ import java.util.Map;
 * Date: 10/20/12
 * Time: 12:05 AM
 */
-enum WidgetButton {
+public enum WidgetButton {
 
     /*digits*/
     one(R.id.oneDigitButton, "1"),