History

app/src/main/java/org/solovyev/android/calculator/App.java

@@ -40,7 +40,10 @@ import android.support.v4.app.FragmentTransaction;
 import android.text.Spannable;
 import android.text.SpannableString;
 import android.text.style.ForegroundColorSpan;
+import android.util.Log;
+
 import com.squareup.otto.Bus;
+
 import org.solovyev.android.Check;
 import org.solovyev.android.UiThreadExecutor;
 import org.solovyev.android.Views;
@@ -49,7 +52,13 @@ import org.solovyev.android.calculator.language.Languages;
 import org.solovyev.android.calculator.onscreen.CalculatorOnscreenService;
 import org.solovyev.android.calculator.view.ScreenMetrics;
 import org.solovyev.android.calculator.wizard.CalculatorWizards;
-import org.solovyev.android.checkout.*;
+import org.solovyev.android.checkout.Billing;
+import org.solovyev.android.checkout.Checkout;
+import org.solovyev.android.checkout.Inventory;
+import org.solovyev.android.checkout.ProductTypes;
+import org.solovyev.android.checkout.Products;
+import org.solovyev.android.checkout.RobotmediaDatabase;
+import org.solovyev.android.checkout.RobotmediaInventory;
 import org.solovyev.android.wizard.Wizards;
 import org.solovyev.common.listeners.JEvent;
 import org.solovyev.common.listeners.JEventListener;
@@ -57,11 +66,13 @@ import org.solovyev.common.listeners.JEventListeners;
 import org.solovyev.common.listeners.Listeners;
 import org.solovyev.common.threads.DelayedExecutor;
 
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 import java.util.Arrays;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
+import java.util.concurrent.ThreadFactory;
+
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
 
 /**
  * User: serso
@@ -119,7 +130,12 @@ public final class App {
     @Nonnull
     private static Wizards wizards;
     @Nonnull
-    private static final Executor initializer = Executors.newSingleThreadExecutor();
+    private static final Executor initThread = Executors.newSingleThreadExecutor(new ThreadFactory() {
+        @Override
+        public Thread newThread(@Nonnull Runnable r) {
+            return new Thread(r, "Init");
+        }
+    });
 
     private App() {
         throw new AssertionError();
@@ -251,8 +267,8 @@ public final class App {
     }
 
     @Nonnull
-    public static Executor getInitializer() {
+    public static Executor getInitThread() {
-        return initializer;
+        return initThread;
     }
 
     @Nonnull

app/src/main/java/org/solovyev/android/calculator/CalculatorActivityLauncher.java

@@ -33,12 +33,16 @@ import android.support.v7.app.AppCompatActivity;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.widget.TextView;
-import jscl.math.Generic;
+
 import org.solovyev.android.Activities;
 import org.solovyev.android.calculator.about.CalculatorAboutActivity;
 import org.solovyev.android.calculator.function.FunctionEditDialogFragment;
 import org.solovyev.android.calculator.history.CalculatorHistoryActivity;
-import org.solovyev.android.calculator.math.edit.*;
+import org.solovyev.android.calculator.math.edit.CalculatorFunctionsActivity;
+import org.solovyev.android.calculator.math.edit.CalculatorOperatorsActivity;
+import org.solovyev.android.calculator.math.edit.CalculatorVarsActivity;
+import org.solovyev.android.calculator.math.edit.CalculatorVarsFragment;
+import org.solovyev.android.calculator.math.edit.VarEditDialogFragment;
 import org.solovyev.android.calculator.matrix.CalculatorMatrixActivity;
 import org.solovyev.android.calculator.plot.CalculatorPlotActivity;
 import org.solovyev.android.calculator.plot.CalculatorPlotter;
@@ -47,9 +51,12 @@ import org.solovyev.common.msg.Message;
 import org.solovyev.common.msg.MessageType;
 import org.solovyev.common.text.Strings;
 
+import java.util.List;
+
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.List;
+
+import jscl.math.Generic;
 
 /**
  * User: serso
@@ -131,8 +138,8 @@ public final class CalculatorActivityLauncher implements CalculatorEventListener
     public static void tryCreateVar(@Nonnull final Context context) {
         final Display display = Locator.getInstance().getDisplay();
         final DisplayState viewState = display.getState();
-        if (viewState.isValid()) {
+        if (viewState.valid) {
-            final String varValue = viewState.getText();
+            final String varValue = viewState.text;
             if (!Strings.isEmpty(varValue)) {
                 if (CalculatorVarsFragment.isValidValue(varValue)) {
                     if (context instanceof AppCompatActivity) {
@@ -158,12 +165,10 @@ public final class CalculatorActivityLauncher implements CalculatorEventListener
         final Display display = Locator.getInstance().getDisplay();
         final DisplayState viewState = display.getState();
 
-        if (viewState.isValid()) {
+        if (viewState.valid) {
-            final String functionValue = viewState.getText();
+            final String functionValue = viewState.text;
             if (!Strings.isEmpty(functionValue)) {
-
                 FunctionEditDialogFragment.showDialog(FunctionEditDialogFragment.Input.newFromDisplay(viewState), context);
-
             } else {
                 getNotifier().showMessage(R.string.empty_function_error, MessageType.error);
             }
@@ -182,8 +187,8 @@ public final class CalculatorActivityLauncher implements CalculatorEventListener
         final Display display = Locator.getInstance().getDisplay();
         final DisplayState viewState = display.getState();
 
-        if (viewState.isValid()) {
+        if (viewState.valid) {
-            final String functionValue = viewState.getText();
+            final String functionValue = viewState.text;
             final Generic expression = viewState.getResult();
             if (!Strings.isEmpty(functionValue) && expression != null) {
                 if (plotter.isPlotPossibleFor(expression)) {

app/src/main/java/org/solovyev/android/calculator/CalculatorApplication.java

@@ -90,7 +90,7 @@ public class CalculatorApplication extends android.app.Application implements Sh
 
         Locator.getInstance().getCalculator().init();
 
-        App.getInitializer().execute(new Runnable() {
+        App.getInitThread().execute(new Runnable() {
             @Override
             public void run() {
                 warmUpEngine();

app/src/main/java/org/solovyev/android/calculator/CalculatorDisplayMenuItem.java

@@ -123,7 +123,7 @@ public enum CalculatorDisplayMenuItem implements LabeledMenuItem<DisplayState> {
 
     public final boolean isItemVisible(@Nonnull DisplayState displayViewState) {
         //noinspection ConstantConditions
-        return displayViewState.isValid() && displayViewState.getResult() != null && isItemVisibleFor(displayViewState.getResult(), displayViewState.getOperation());
+        return displayViewState.valid && displayViewState.getResult() != null && isItemVisibleFor(displayViewState.getResult(), displayViewState.getOperation());
     }
 
     protected boolean isItemVisibleFor(@Nonnull Generic generic, @Nonnull JsclOperation operation) {

app/src/main/java/org/solovyev/android/calculator/CalculatorDisplayOnClickListener.java

@@ -24,13 +24,15 @@ package org.solovyev.android.calculator;
 
 import android.support.v4.app.FragmentActivity;
 import android.view.View;
+
 import org.solovyev.android.menu.ContextMenuBuilder;
 import org.solovyev.android.menu.ListContextMenu;
 
-import javax.annotation.Nonnull;
 import java.util.ArrayList;
 import java.util.List;
 
+import javax.annotation.Nonnull;
+
 /**
  * User: Solovyev_S
  * Date: 21.09.12
@@ -52,7 +54,7 @@ public class CalculatorDisplayOnClickListener implements View.OnClickListener {
 
             final DisplayState displayViewState = cd.getState();
 
-            if (displayViewState.isValid()) {
+            if (displayViewState.valid) {
                 final List<CalculatorDisplayMenuItem> filteredMenuItems = new ArrayList<CalculatorDisplayMenuItem>(CalculatorDisplayMenuItem.values().length);
                 for (CalculatorDisplayMenuItem menuItem : CalculatorDisplayMenuItem.values()) {
                     if (menuItem.isItemVisible(displayViewState)) {
@@ -65,10 +67,8 @@ public class CalculatorDisplayOnClickListener implements View.OnClickListener {
                 }
 
             } else {
-                final String errorMessage = displayViewState.getErrorMessage();
+                final String errorMessage = displayViewState.text;
-                if (errorMessage != null) {
+                Locator.getInstance().getCalculator().fireCalculatorEvent(CalculatorEventType.show_evaluation_error, errorMessage, activity);
-                    Locator.getInstance().getCalculator().fireCalculatorEvent(CalculatorEventType.show_evaluation_error, errorMessage, activity);
-                }
             }
         }
     }

app/src/main/java/org/solovyev/android/calculator/CalculatorImpl.java

@@ -23,16 +23,9 @@
 package org.solovyev.android.calculator;
 
 import android.text.TextUtils;
+
 import com.squareup.otto.Subscribe;
-import jscl.AbstractJsclArithmeticException;
+
-import jscl.NumeralBase;
-import jscl.NumeralBaseException;
-import jscl.math.Generic;
-import jscl.math.function.Function;
-import jscl.math.function.IConstant;
-import jscl.math.operator.Operator;
-import jscl.text.ParseInterruptedException;
-import org.solovyev.android.calculator.history.CalculatorHistory;
 import org.solovyev.android.calculator.jscl.JsclOperation;
 import org.solovyev.android.calculator.model.Var;
 import org.solovyev.android.calculator.text.TextProcessor;
@@ -45,14 +38,24 @@ import org.solovyev.common.text.Strings;
 import org.solovyev.common.units.ConversionException;
 import org.solovyev.common.units.Conversions;
 
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.concurrent.Executors;
 import java.util.concurrent.atomic.AtomicLong;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import jscl.AbstractJsclArithmeticException;
+import jscl.NumeralBase;
+import jscl.NumeralBaseException;
+import jscl.math.Generic;
+import jscl.math.function.Function;
+import jscl.math.function.IConstant;
+import jscl.math.operator.Operator;
+import jscl.text.ParseInterruptedException;
+
 /**
  * User: Solovyev_S
  * Date: 20.09.12
@@ -486,11 +489,11 @@ public class CalculatorImpl implements Calculator, CalculatorEventListener {
     @Subscribe
     public void onDisplayChanged(@Nonnull Display.ChangedEvent e) {
         final DisplayState newState = e.newState;
-        if (!newState.isValid()) {
+        if (!newState.valid) {
             return;
         }
-        final String result = newState.getStringResult();
+        final String text = newState.text;
-        if (TextUtils.isEmpty(result)) {
+        if (TextUtils.isEmpty(text)) {
             return;
         }
         final CalculatorMathRegistry<IConstant> varsRegistry = Locator.getInstance().getEngine().getVarsRegistry();
@@ -498,7 +501,7 @@ public class CalculatorImpl implements Calculator, CalculatorEventListener {
 
         final Var.Builder builder = ansVar != null ? new Var.Builder(ansVar) : new Var.Builder();
         builder.setName(CalculatorVarsRegistry.ANS);
-        builder.setValue(result);
+        builder.setValue(text);
         builder.setDescription(CalculatorMessages.getBundle().getString(CalculatorMessages.ans_description));
 
         CalculatorVarsRegistry.saveVariable(varsRegistry, builder, ansVar, this, false);

app/src/main/java/org/solovyev/android/calculator/CalculatorKeyboard.java

@@ -116,14 +116,12 @@ public class CalculatorKeyboard {
     }
 
     public void copyButtonPressed() {
-        final DisplayState displayViewState = Locator.getInstance().getDisplay().getState();
+        final DisplayState displayState = Locator.getInstance().getDisplay().getState();
-        if (displayViewState.isValid()) {
+        if (!displayState.valid) {
-            final CharSequence text = displayViewState.getText();
+            return;
-            if (!Strings.isEmpty(text)) {
-                Locator.getInstance().getClipboard().setText(text);
-                Locator.getInstance().getNotifier().showMessage(CalculatorMessage.newInfoMessage(CalculatorMessages.result_copied));
-            }
         }
+        Locator.getInstance().getClipboard().setText(displayState.text);
+        Locator.getInstance().getNotifier().showMessage(CalculatorMessage.newInfoMessage(CalculatorMessages.result_copied));
     }
 
     public void moveCursorLeft() {

app/src/main/java/org/solovyev/android/calculator/CalculatorSpecialButton.java

@@ -22,12 +22,11 @@
 
 package org.solovyev.android.calculator;
 
-import org.solovyev.common.text.Strings;
+import java.util.HashMap;
+import java.util.Map;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.HashMap;
-import java.util.Map;
 
 /**
  * User: serso
@@ -115,13 +114,11 @@ public enum CalculatorSpecialButton {
                 return;
             }
 
-            final DisplayState displayViewState = Locator.getInstance().getDisplay().getState();
+            final DisplayState displayState = Locator.getInstance().getDisplay().getState();
-            if (displayViewState.isValid()) {
+            if (!displayState.valid) {
-                final CharSequence text = displayViewState.getText();
+                return;
-                if (!Strings.isEmpty(text)) {
-                    Locator.getInstance().getEditor().setText(text.toString());
-                }
             }
+            Locator.getInstance().getEditor().setText(displayState.text);
         }
     },
     clear("clear") {

app/src/main/java/org/solovyev/android/calculator/DisplayState.java

@@ -23,47 +23,43 @@
 package org.solovyev.android.calculator;
 
 import android.text.TextUtils;
-import jscl.math.Generic;
+
+import org.json.JSONException;
 import org.json.JSONObject;
 import org.solovyev.android.calculator.jscl.JsclOperation;
-import org.solovyev.common.text.Strings;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
+import jscl.math.Generic;
+
 public class DisplayState {
 
+    private static final String JSON_TEXT = "t";
     @Nonnull
-    private static final String JSON_OPERATION = "o";
+    public final String text;
+    public final boolean valid;
+    public final long sequence;
     @Nonnull
-    private JsclOperation operation = JsclOperation.numeric;
+    private transient JsclOperation operation = JsclOperation.numeric;
-
     @Nullable
     private transient Generic result;
 
-    @Nullable
+    private DisplayState(@Nonnull String text, boolean valid, long sequence) {
-    private String stringResult = "";
+        this.text = text;
-
+        this.valid = valid;
-    private boolean valid = true;
+        this.sequence = sequence;
-
-    @Nullable
-    private String errorMessage;
-
-    private long sequence;
-
-    private DisplayState() {
     }
 
-    private DisplayState(@Nonnull JSONObject json) {
+    DisplayState(@Nonnull JSONObject json) {
-        operation = JsclOperation.values()[json.optInt(JSON_OPERATION, JsclOperation.numeric.ordinal())];
+        this(json.optString(JSON_TEXT), true, EditorState.NO_SEQUENCE);
     }
 
     @Nonnull
     public static DisplayState empty() {
-        return new DisplayState();
+        return new DisplayState("", true, EditorState.NO_SEQUENCE);
     }
 
-
     @Nonnull
     public static DisplayState create(@Nonnull JSONObject json) {
         return new DisplayState(json);
@@ -73,11 +69,8 @@ public class DisplayState {
     public static DisplayState createError(@Nonnull JsclOperation operation,
                                            @Nonnull String errorMessage,
                                            long sequence) {
-        final DisplayState state = new DisplayState();
+        final DisplayState state = new DisplayState(errorMessage, false, sequence);
-        state.valid = false;
-        state.errorMessage = errorMessage;
         state.operation = operation;
-        state.sequence = sequence;
         return state;
     }
 
@@ -86,49 +79,30 @@ public class DisplayState {
                                            @Nullable Generic result,
                                            @Nonnull String stringResult,
                                            long sequence) {
-        final DisplayState state = new DisplayState();
+        final DisplayState state = new DisplayState(stringResult, true, sequence);
-        state.valid = true;
         state.result = result;
-        state.stringResult = stringResult;
         state.operation = operation;
-        state.sequence = sequence;
         return state;
     }
 
-    @Nonnull
-    public String getText() {
-        return Strings.getNotEmpty(isValid() ? stringResult : errorMessage, "");
-    }
-
     @Nullable
     public Generic getResult() {
         return this.result;
     }
 
-    public boolean isValid() {
-        return this.valid;
-    }
-
-    @Nullable
-    public String getErrorMessage() {
-        return this.errorMessage;
-    }
-
-    @Nullable
-    public String getStringResult() {
-        return stringResult;
-    }
-
     @Nonnull
     public JsclOperation getOperation() {
         return this.operation;
     }
 
-    public long getSequence() {
+    public boolean same(@Nonnull DisplayState that) {
-        return sequence;
+        return TextUtils.equals(text, that.text) && operation == that.operation;
     }
 
-    public boolean same(@Nonnull DisplayState that) {
+    @Nonnull
-        return TextUtils.equals(stringResult, that.stringResult) && TextUtils.equals(errorMessage, that.errorMessage) && operation == that.operation;
+    public JSONObject toJson() throws JSONException {
+        final JSONObject json = new JSONObject();
+        json.put(JSON_TEXT, text);
+        return json;
     }
 }

app/src/main/java/org/solovyev/android/calculator/DisplayView.java

@@ -89,7 +89,7 @@ public class DisplayView extends AutoResizeTextView {
         Check.isMainThread();
 
         state = newState;
-        if (state.isValid()) {
+        if (state.valid) {
             setText(highlightText(state));
             setTextColor(getTextColor().normal);
         } else {
@@ -100,7 +100,7 @@ public class DisplayView extends AutoResizeTextView {
 
     @NonNull
     private CharSequence highlightText(@Nonnull DisplayState state) {
-        final String text = state.getStringResult();
+        final String text = state.text;
         if (TextUtils.isEmpty(text)) {
             return "";
         }

app/src/main/java/org/solovyev/android/calculator/EditorState.java

@@ -33,9 +33,7 @@ import javax.annotation.Nullable;
 public class EditorState {
 
     public static final long NO_SEQUENCE = -1;
-    @Nonnull
     private static final String JSON_TEXT = "t";
-    @Nonnull
     private static final String JSON_SELECTION = "s";
     private static long counter = NO_SEQUENCE + 1;
 

app/src/main/java/org/solovyev/android/calculator/function/FunctionEditDialogFragment.java

@@ -311,7 +311,7 @@ public class FunctionEditDialogFragment extends DialogFragment implements Calcul
         public static Input newFromDisplay(@Nonnull DisplayState viewState) {
             final Input result = new Input();
 
-            result.content = viewState.getText();
+            result.content = viewState.text;
             final Generic generic = viewState.getResult();
             if (generic != null) {
                 final Set<Constant> constants = CalculatorUtils.getNotSystemConstants(generic);

app/src/main/java/org/solovyev/android/calculator/history/BaseHistoryFragment.java

@@ -30,18 +30,38 @@ import android.os.Bundle;
 import android.support.v4.app.FragmentActivity;
 import android.support.v4.app.ListFragment;
 import android.text.ClipboardManager;
-import android.view.*;
+import android.view.ContextMenu;
-import android.widget.*;
+import android.view.LayoutInflater;
+import android.view.MenuItem;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.AdapterView;
+import android.widget.ArrayAdapter;
+import android.widget.EditText;
+import android.widget.ListView;
+import android.widget.TextView;
+import android.widget.Toast;
+
 import com.melnykov.fab.FloatingActionButton;
-import org.solovyev.android.calculator.*;
+
+import org.solovyev.android.calculator.App;
+import org.solovyev.android.calculator.CalculatorActivity;
+import org.solovyev.android.calculator.CalculatorEventData;
+import org.solovyev.android.calculator.CalculatorEventListener;
+import org.solovyev.android.calculator.CalculatorEventType;
+import org.solovyev.android.calculator.CalculatorFragmentType;
+import org.solovyev.android.calculator.FragmentUi;
+import org.solovyev.android.calculator.Locator;
+import org.solovyev.android.calculator.R;
 import org.solovyev.android.calculator.jscl.JsclOperation;
 import org.solovyev.common.text.Strings;
 
-import javax.annotation.Nonnull;
-import javax.annotation.Nullable;
 import java.util.ArrayList;
 import java.util.List;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 import static android.view.Menu.NONE;
 import static org.solovyev.android.calculator.CalculatorEventType.clear_history_requested;
 
@@ -71,7 +91,7 @@ public abstract class BaseHistoryFragment extends ListFragment implements Calcul
 
     @Nonnull
     public static String getHistoryText(@Nonnull HistoryState state) {
-        return state.editor.getTextString() + getIdentitySign(state.display.getOperation()) + state.display.getText();
+        return state.editor.getTextString() + getIdentitySign(state.display.getOperation()) + state.display.text;
     }
 
     @Nonnull
@@ -185,7 +205,7 @@ public abstract class BaseHistoryFragment extends ListFragment implements Calcul
                 }
                 return true;
             case R.string.c_copy_result:
-                final String displayText = state.display.getText();
+                final String displayText = state.display.text;
                 if (!Strings.isEmpty(displayText)) {
                     final ClipboardManager clipboard = (ClipboardManager) context.getSystemService(Activity.CLIPBOARD_SERVICE);
                     clipboard.setText(displayText);
@@ -200,7 +220,7 @@ public abstract class BaseHistoryFragment extends ListFragment implements Calcul
                 return true;
             case R.string.c_remove:
                 getAdapter().remove(state);
-                Locator.getInstance().getHistory().removeSavedHistory(state);
+                Locator.getInstance().getHistory().removeSaved(state);
                 Toast.makeText(context, context.getText(R.string.c_history_was_removed), Toast.LENGTH_LONG).show();
                 getAdapter().notifyDataSetChanged();
                 return true;
@@ -226,7 +246,7 @@ public abstract class BaseHistoryFragment extends ListFragment implements Calcul
                     @Override
                     public void onClick(DialogInterface dialog, int which) {
                         /*if (save) {
-                            final HistoryState savedHistoryItem = Locator.getInstance().getHistory().addSavedState(state);
+                            final HistoryState savedHistoryItem = Locator.getInstance().getHistory().addSaved(state);
                             savedHistoryItem.setComment(comment.getText().toString());
                             Locator.getInstance().getHistory().save();
                             // we don't need to add element to the adapter as adapter of another activity must be updated and not this
@@ -245,7 +265,7 @@ public abstract class BaseHistoryFragment extends ListFragment implements Calcul
     }
 
     private boolean shouldHaveCopyResult(@Nonnull HistoryState state) {
-        return !state.display.isValid() || !Strings.isEmpty(state.display.getText());
+        return !state.display.valid || !Strings.isEmpty(state.display.text);
     }
 
     @Override

app/src/main/java/org/solovyev/android/calculator/history/CalculatorHistory.java

@@ -23,32 +23,48 @@
 package org.solovyev.android.calculator.history;
 
 import android.content.SharedPreferences;
+import android.support.annotation.NonNull;
 import android.text.TextUtils;
+
 import com.google.common.base.Strings;
 import com.squareup.otto.Subscribe;
+
+import org.json.JSONArray;
+import org.json.JSONException;
 import org.solovyev.android.Check;
-import org.solovyev.android.calculator.*;
+import org.solovyev.android.calculator.App;
+import org.solovyev.android.calculator.CalculatorEventType;
+import org.solovyev.android.calculator.Display;
+import org.solovyev.android.calculator.DisplayState;
+import org.solovyev.android.calculator.Editor;
+import org.solovyev.android.calculator.EditorState;
+import org.solovyev.android.calculator.Locator;
+import org.solovyev.android.io.FileLoader;
 import org.solovyev.android.io.FileSaver;
 
-import javax.annotation.Nonnull;
+import java.io.File;
-import javax.annotation.Nullable;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
 public class CalculatorHistory {
 
+    public static final String TAG = App.subTag("History");
     @Nonnull
     private final HistoryList current = new HistoryList();
     @Nonnull
     private final List<HistoryState> saved = new ArrayList<>();
     @Nullable
     private EditorState lastEditorState;
+    private boolean initialized;
 
     public CalculatorHistory() {
         App.getBus().register(this);
-        App.getInitializer().execute(new Runnable() {
+        App.getInitThread().execute(new Runnable() {
             @Override
             public void run() {
                 init();
@@ -57,54 +73,97 @@ public class CalculatorHistory {
     }
 
     private static void migrateOldHistory() {
-        final SharedPreferences preferences = App.getPreferences();
+        try {
-        final String xml = preferences.getString("org.solovyev.android.calculator.CalculatorModel_history", null);
+            final SharedPreferences preferences = App.getPreferences();
-        if (TextUtils.isEmpty(xml)) {
+            final String xml = preferences.getString("org.solovyev.android.calculator.CalculatorModel_history", null);
-            return;
+            if (TextUtils.isEmpty(xml)) {
+                return;
+            }
+            final OldHistory history = OldHistory.fromXml(xml);
+            if (history == null) {
+                // strange, history seems to be broken. Avoid clearing the preference
+                return;
+            }
+            final List<HistoryState> states = new ArrayList<>();
+            for (OldHistoryState state : history.getItems()) {
+                final OldEditorHistoryState oldEditorState = state.getEditorState();
+                final OldDisplayHistoryState oldDisplayState = state.getDisplayState();
+                final String editorText = oldEditorState.getText();
+                final EditorState editor = EditorState.create(Strings.nullToEmpty(editorText), oldEditorState.getCursorPosition());
+                final DisplayState display = oldDisplayState.isValid()
+                        ? DisplayState.createValid(oldDisplayState.getJsclOperation(), null, Strings.nullToEmpty(oldDisplayState.getEditorState().getText()), EditorState.NO_SEQUENCE)
+                        : DisplayState.createError(oldDisplayState.getJsclOperation(), "", EditorState.NO_SEQUENCE);
+                states.add(HistoryState.newBuilder(editor, display).build());
+            }
+            final JSONArray json = HistoryList.toJson(states);
+            FileSaver.save(getSavedHistoryFile(), json.toString());
+        } catch (Exception e) {
+            Locator.getInstance().getLogger().error(TAG, e.getMessage(), e);
         }
-        final OldHistory history = OldHistory.fromXml(xml);
+    }
-        if (history == null) {
+
-            // strange, history seems to be broken. Avoid clearing the preference
+    @NonNull
-            return;
+    private static File getSavedHistoryFile() {
+        return new File(App.getApplication().getFilesDir(), "history-saved.json");
+    }
+
+    @NonNull
+    private static File getCurrentHistoryFile() {
+        return new File(App.getApplication().getFilesDir(), "history-current.json");
+    }
+
+    @Nonnull
+    private static List<HistoryState> loadStates(@Nonnull File file) {
+        final CharSequence json = FileLoader.load(file);
+        if (TextUtils.isEmpty(json)) {
+            return Collections.emptyList();
         }
-        final List<HistoryState> states = new ArrayList<>();
+        try {
-        for (OldHistoryState state : history.getItems()) {
+            return HistoryList.fromJson(new JSONArray(json.toString()));
-            final OldEditorHistoryState oldEditorState = state.getEditorState();
+        } catch (JSONException e) {
-            final OldDisplayHistoryState oldDisplayState = state.getDisplayState();
+            Locator.getInstance().getLogger().error(TAG, e.getMessage(), e);
-            final String editorText = oldEditorState.getText();
-            final EditorState editor = EditorState.create(Strings.nullToEmpty(editorText), oldEditorState.getCursorPosition());
-            final DisplayState display = oldDisplayState.isValid()
-                    ? DisplayState.createValid(oldDisplayState.getJsclOperation(), null, Strings.nullToEmpty(oldDisplayState.getEditorState().getText()), EditorState.NO_SEQUENCE)
-                    : DisplayState.createError(oldDisplayState.getJsclOperation(), "", EditorState.NO_SEQUENCE);
-            states.add(HistoryState.newBuilder(editor, display).build());
         }
+        return Collections.emptyList();
     }
 
     private void init() {
         Check.isNotMainThread();
         migrateOldHistory();
+        final List<HistoryState> currentStates = loadStates(getCurrentHistoryFile());
+        final List<HistoryState> savedStates = loadStates(getSavedHistoryFile());
+        App.getHandler().post(new Runnable() {
+            @Override
+            public void run() {
+                current.addAll(currentStates);
+                saved.addAll(savedStates);
+                initialized = true;
+            }
+        });
     }
 
-    public boolean isEmpty() {
+    public void addCurrent(@Nonnull HistoryState state) {
-        Check.isMainThread();
-        return current.isEmpty();
-    }
-
-    public void addCurrentState(@Nonnull HistoryState state) {
         Check.isMainThread();
         current.add(state);
         Locator.getInstance().getCalculator().fireCalculatorEvent(CalculatorEventType.history_state_added, state);
-        // todo serso: schedule save
+        onCurrentChanged();
     }
 
-    public void addSavedState(@Nonnull HistoryState state) {
+    public void addSaved(@Nonnull HistoryState state) {
         Check.isMainThread();
         saved.add(state);
-        // todo serso: schedule save
+        onSavedChanged();
+    }
+
+    private void onCurrentChanged() {
+        // todo serso: implement
+    }
+
+    private void onSavedChanged() {
+        // todo serso: implement
     }
 
     @Nonnull
-    public List<HistoryState> getCurrentHistory() {
+    public List<HistoryState> getCurrent() {
         Check.isMainThread();
 
         final List<HistoryState> result = new LinkedList<>();
@@ -122,6 +181,12 @@ public class CalculatorHistory {
         return result;
     }
 
+    @Nonnull
+    public List<HistoryState> getSaved() {
+        Check.isMainThread();
+        return Collections.unmodifiableList(saved);
+    }
+
     private boolean isIntermediate(@Nonnull String newerText,
                                    @Nonnull String olderText) {
         final int diff = newerText.length() - olderText.length();
@@ -136,9 +201,16 @@ public class CalculatorHistory {
         return false;
     }
 
-    public void clear() {
+    public void clearCurrent() {
         Check.isMainThread();
         current.clear();
+        onCurrentChanged();
+    }
+
+    public void clearSaved() {
+        Check.isMainThread();
+        saved.clear();
+        onSavedChanged();
     }
 
     public void undo() {
@@ -146,7 +218,7 @@ public class CalculatorHistory {
         if (state == null) {
             return;
         }
-        onCurrentStateChanged(state);
+        applyHistoryState(state);
     }
 
     public void redo() {
@@ -154,41 +226,46 @@ public class CalculatorHistory {
         if (state == null) {
             return;
         }
-        onCurrentStateChanged(state);
+        applyHistoryState(state);
     }
 
-    private void onCurrentStateChanged(@Nonnull HistoryState state) {
+    private void applyHistoryState(@Nonnull HistoryState state) {
         App.getEditor().setState(state.editor);
         App.getDisplay().setState(state.display);
     }
 
-    @Nonnull
+    public void removeSaved(@Nonnull HistoryState state) {
-    public List<HistoryState> getSavedHistory() {
+        Check.isMainThread();
-        return Collections.unmodifiableList(saved);
-    }
-
-    public void clearSavedHistory() {
-        saved.clear();
-    }
-
-    public void removeSavedHistory(@Nonnull HistoryState state) {
         saved.remove(state);
+        onSavedChanged();
+    }
+
+    public void removeCurrent(@Nonnull HistoryState state) {
+        Check.isMainThread();
+        current.remove(state);
+        onCurrentChanged();
     }
 
     @Subscribe
     public void onEditorChanged(@Nonnull Editor.ChangedEvent e) {
+        if (!initialized) {
+            return;
+        }
         lastEditorState = e.newState;
     }
 
     @Subscribe
     public void onDisplayChanged(@Nonnull Display.ChangedEvent e) {
+        if (!initialized) {
+            return;
+        }
         if (lastEditorState == null) {
             return;
         }
-        if (lastEditorState.sequence != e.newState.getSequence()) {
+        if (lastEditorState.sequence != e.newState.sequence) {
             return;
         }
-        addCurrentState(HistoryState.newBuilder(lastEditorState, e.newState).build());
+        addCurrent(HistoryState.newBuilder(lastEditorState, e.newState).build());
         lastEditorState = null;
     }
 }

app/src/main/java/org/solovyev/android/calculator/history/HistoryFragment.java

@@ -44,12 +44,12 @@ public class HistoryFragment extends BaseHistoryFragment {
     @Nonnull
     @Override
     protected List<HistoryState> getHistoryItems() {
-        return Locator.getInstance().getHistory().getCurrentHistory();
+        return Locator.getInstance().getHistory().getCurrent();
     }
 
     @Override
     protected void clearHistory() {
-        Locator.getInstance().getHistory().clear();
+        Locator.getInstance().getHistory().clearCurrent();
         getAdapter().clear();
     }
 }

app/src/main/java/org/solovyev/android/calculator/history/HistoryItemMenuData.java

@@ -1,56 +0,0 @@
-/*
- * Copyright 2013 serso aka se.solovyev
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *    http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- * Contact details
- *
- * Email: se.solovyev@gmail.com
- * Site:  http://se.solovyev.org
- */
-
-package org.solovyev.android.calculator.history;
-
-import android.widget.ArrayAdapter;
-
-import javax.annotation.Nonnull;
-
-/**
- * User: serso
- * Date: 12/18/11
- * Time: 3:10 PM
- */
-public class HistoryItemMenuData {
-
-    @Nonnull
-    private final ArrayAdapter<OldHistoryState> adapter;
-
-    @Nonnull
-    private final OldHistoryState historyState;
-
-    public HistoryItemMenuData(@Nonnull OldHistoryState historyState, ArrayAdapter<OldHistoryState> adapter) {
-        this.historyState = historyState;
-        this.adapter = adapter;
-    }
-
-    @Nonnull
-    public OldHistoryState getHistoryState() {
-        return historyState;
-    }
-
-    @Nonnull
-    public ArrayAdapter<OldHistoryState> getAdapter() {
-        return adapter;
-    }
-}

app/src/main/java/org/solovyev/android/calculator/history/HistoryList.java

@@ -2,8 +2,14 @@ package org.solovyev.android.calculator.history;
 
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
+import android.util.Log;
+
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
 import org.solovyev.android.Check;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
@@ -32,6 +38,26 @@ public class HistoryList {
         }
     }
 
+    public void addAll(@NonNull List<HistoryState> states) {
+        for (HistoryState state : states) {
+            add(state);
+        }
+    }
+
+    public void remove(@NonNull HistoryState state) {
+        Check.isMainThread();
+        for (int i = 0; i < list.size(); i++) {
+            final HistoryState candidate = list.get(i);
+            if (candidate.same(state)) {
+                list.remove(i);
+                if (current >= i) {
+                    current--;
+                }
+                break;
+            }
+        }
+    }
+
     private boolean isCurrent(@NonNull HistoryState state) {
         final HistoryState current = getCurrent();
         if (current == null) {
@@ -86,4 +112,35 @@ public class HistoryList {
     public List<HistoryState> asList() {
         return Collections.unmodifiableList(list);
     }
+
+    @NonNull
+    public static JSONArray toJson(@NonNull List<HistoryState> states) {
+        final JSONArray array = new JSONArray();
+        for (int i = 0; i < states.size(); i++) {
+            final HistoryState state = states.get(i);
+            try {
+                array.put(i, state.toJson());
+            } catch (JSONException e) {
+                Log.e(CalculatorHistory.TAG, e.getMessage(), e);
+            }
+        }
+        return array;
+    }
+
+    @NonNull
+    public static List<HistoryState> fromJson(@NonNull JSONArray array) {
+        final List<HistoryState> states = new ArrayList<>(array.length());
+        for (int i = 0; i < array.length(); i++) {
+            final JSONObject json = array.optJSONObject(i);
+            if (json == null) {
+                continue;
+            }
+            try {
+                states.add(HistoryState.create(json));
+            } catch (JSONException e) {
+                Log.e(CalculatorHistory.TAG, e.getMessage(), e);
+            }
+        }
+        return states;
+    }
 }

app/src/main/java/org/solovyev/android/calculator/history/HistoryState.java

@@ -1,6 +1,7 @@
 package org.solovyev.android.calculator.history;
 
-import android.support.annotation.Nullable;
+import android.text.TextUtils;
+
 import org.json.JSONException;
 import org.json.JSONObject;
 import org.solovyev.android.Check;
@@ -11,17 +12,18 @@ import javax.annotation.Nonnull;
 
 public class HistoryState {
 
-    @Nonnull
     private static final String JSON_EDITOR = "e";
-    @Nonnull
     private static final String JSON_DISPLAY = "d";
+    private static final String JSON_TIME = "t";
+    private static final String JSON_COMMENT = "c";
+
     @Nonnull
     public final EditorState editor;
     @Nonnull
     public final DisplayState display;
     protected long time;
-    @Nullable
+    @Nonnull
-    protected String comment;
+    protected String comment = "";
 
     private HistoryState(@Nonnull EditorState editor, @Nonnull DisplayState display) {
         this.editor = editor;
@@ -30,6 +32,8 @@ public class HistoryState {
 
     private HistoryState(@Nonnull JSONObject json) throws JSONException {
         this(EditorState.create(json.getJSONObject(JSON_EDITOR)), DisplayState.create(json.getJSONObject(JSON_DISPLAY)));
+        this.time = json.optLong(JSON_TIME, 0L);
+        this.comment = json.optString(JSON_COMMENT, "");
     }
 
     @Nonnull
@@ -37,6 +41,23 @@ public class HistoryState {
         return new Builder(editor, display);
     }
 
+    @Nonnull
+    public static HistoryState create(@Nonnull JSONObject json) throws JSONException {
+        return new HistoryState(json);
+    }
+
+    @Nonnull
+    public JSONObject toJson() throws JSONException {
+        final JSONObject json = new JSONObject();
+        json.put(JSON_EDITOR, editor.toJson());
+        json.put(JSON_DISPLAY, display.toJson());
+        json.put(JSON_TIME, time);
+        if (!TextUtils.isEmpty(comment)) {
+            json.put(JSON_COMMENT, comment);
+        }
+        return json;
+    }
+
     @Nonnull
     public EditorState getEditor() {
         return editor;
@@ -51,7 +72,7 @@ public class HistoryState {
         return time;
     }
 
-    @Nullable
+    @Nonnull
     public String getComment() {
         return comment;
     }
@@ -74,7 +95,7 @@ public class HistoryState {
             this.time = time;
         }
 
-        public void setComment(@Nullable String comment) {
+        public void setComment(@Nonnull String comment) {
             Check.isTrue(!built);
             this.comment = comment;
         }

app/src/main/java/org/solovyev/android/calculator/history/SavedHistoryFragment.java

@@ -45,12 +45,12 @@ public class SavedHistoryFragment extends BaseHistoryFragment {
     @Nonnull
     @Override
     protected List<HistoryState> getHistoryItems() {
-        return new ArrayList<>(Locator.getInstance().getHistory().getSavedHistory());
+        return new ArrayList<>(Locator.getInstance().getHistory().getSaved());
     }
 
     @Override
     protected void clearHistory() {
-        Locator.getInstance().getHistory().clearSavedHistory();
+        Locator.getInstance().getHistory().clearSaved();
         getAdapter().clear();
     }
 }

app/src/main/java/org/solovyev/android/calculator/widget/CalculatorWidget.java

@@ -40,19 +40,29 @@ import android.text.SpannedString;
 import android.text.TextUtils;
 import android.text.style.StyleSpan;
 import android.widget.RemoteViews;
+
 import org.solovyev.android.Check;
 import org.solovyev.android.Views;
-import org.solovyev.android.calculator.*;
+import org.solovyev.android.calculator.App;
+import org.solovyev.android.calculator.CalculatorButton;
+import org.solovyev.android.calculator.DisplayState;
+import org.solovyev.android.calculator.EditorState;
+import org.solovyev.android.calculator.Locator;
 import org.solovyev.android.calculator.Preferences.SimpleTheme;
+import org.solovyev.android.calculator.R;
+
+import java.util.EnumMap;
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import java.util.EnumMap;
 
 import static android.appwidget.AppWidgetManager.OPTION_APPWIDGET_MIN_HEIGHT;
 import static android.content.Intent.ACTION_CONFIGURATION_CHANGED;
 import static android.os.Build.VERSION_CODES.JELLY_BEAN;
-import static org.solovyev.android.calculator.CalculatorBroadcaster.*;
+import static org.solovyev.android.calculator.CalculatorBroadcaster.ACTION_DISPLAY_STATE_CHANGED;
+import static org.solovyev.android.calculator.CalculatorBroadcaster.ACTION_EDITOR_STATE_CHANGED;
+import static org.solovyev.android.calculator.CalculatorBroadcaster.ACTION_INIT;
+import static org.solovyev.android.calculator.CalculatorBroadcaster.ACTION_THEME_CHANGED;
 import static org.solovyev.android.calculator.CalculatorReceiver.newButtonClickedIntent;
 
 public class CalculatorWidget extends AppWidgetProvider {
@@ -208,9 +218,9 @@ public class CalculatorWidget extends AppWidgetProvider {
     }
 
     private void updateDisplayState(@Nonnull Context context, @Nonnull RemoteViews views, @Nonnull DisplayState displayState, @Nonnull SimpleTheme theme) {
-        final boolean error = !displayState.isValid();
+        final boolean error = !displayState.valid;
         if (!error) {
-            views.setTextViewText(R.id.calculator_display, displayState.getText());
+            views.setTextViewText(R.id.calculator_display, displayState.text);
         }
         views.setTextColor(R.id.calculator_display, ContextCompat.getColor(context, theme.getDisplayTextColor(error)));
     }

app/src/main/java/org/solovyev/android/io/BaseIoLoader.java

@@ -1,7 +1,5 @@
 package org.solovyev.android.io;
 
-import android.content.Context;
-import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.util.Log;
 
@@ -10,14 +8,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 
-abstract class BaseFileLoader {
+public abstract class BaseIoLoader {
-
-    @NonNull
-    protected final Context context;
-
-    public BaseFileLoader(@NonNull Context context) {
-        this.context = context;
-    }
 
     @Nullable
     public CharSequence load() {

app/src/main/java/org/solovyev/android/io/BaseIoSaver.java

@@ -8,12 +8,12 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStreamWriter;
 
-public abstract class BaseFileSaver implements Runnable {
+public abstract class BaseIoSaver implements Runnable {
 
     @NonNull
     private final CharSequence data;
 
-    protected BaseFileSaver(@NonNull CharSequence data) {
+    protected BaseIoSaver(@NonNull CharSequence data) {
         this.data = data;
     }
 

app/src/main/java/org/solovyev/android/io/FileLoader.java

@@ -0,0 +1,31 @@
+package org.solovyev.android.io;
+
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+public class FileLoader extends BaseIoLoader {
+
+    @NonNull
+    private final File file;
+
+    public FileLoader(@NonNull File file) {
+        this.file = file;
+    }
+
+    @Nullable
+    public static CharSequence load(@NonNull File file) {
+        final FileLoader loader = new FileLoader(file);
+        return loader.load();
+    }
+
+    @Nullable
+    @Override
+    protected InputStream getInputStream() throws IOException {
+        return new FileInputStream(file);
+    }
+}

app/src/main/java/org/solovyev/android/io/FileSaver.java

@@ -6,7 +6,7 @@ import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.FileOutputStream;
 
-public class FileSaver extends BaseFileSaver {
+public class FileSaver extends BaseIoSaver {
 
     @NonNull
     private final File file;

app/src/test/java/org/solovyev/android/calculator/CalculatorTestUtils.java

@@ -23,20 +23,28 @@
 package org.solovyev.android.calculator;
 
 import android.content.Context;
-import jscl.JsclMathEngine;
+
 import org.junit.Assert;
 import org.mockito.Mockito;
 import org.solovyev.android.calculator.history.CalculatorHistory;
 import org.solovyev.android.calculator.jscl.JsclOperation;
 import org.solovyev.android.calculator.plot.CalculatorPlotter;
 
-import javax.annotation.Nonnull;
+import java.io.ByteArrayInputStream;
-import javax.annotation.Nullable;
+import java.io.ByteArrayOutputStream;
-import java.io.*;
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
 import java.text.DecimalFormatSymbols;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+
+import jscl.JsclMathEngine;
+
 /**
  * User: serso
  * Date: 10/7/12
@@ -103,7 +111,7 @@ public class CalculatorTestUtils {
 
             if (latch.await(TIMEOUT, TimeUnit.SECONDS)) {
                 Assert.assertNotNull(calculatorEventListener.getResult());
-                Assert.assertEquals(expected, calculatorEventListener.getResult().getText());
+                Assert.assertEquals(expected, calculatorEventListener.getResult().text);
             } else {
                 Assert.fail("Too long wait for: " + expression);
             }
@@ -158,7 +166,7 @@ public class CalculatorTestUtils {
 
             if (latch.await(TIMEOUT, TimeUnit.SECONDS)) {
                 Assert.assertNotNull(calculatorEventListener.getResult());
-                Assert.assertFalse(calculatorEventListener.getResult().isValid());
+                Assert.assertFalse(calculatorEventListener.getResult().valid);
             } else {
                 Assert.fail("Too long wait for: " + expression);
             }

app/src/test/java/org/solovyev/android/calculator/history/CalculatorHistoryTest.java

@@ -29,9 +29,10 @@ import org.solovyev.android.calculator.CalculatorTestUtils;
 import org.solovyev.android.calculator.DisplayState;
 import org.solovyev.android.calculator.EditorState;
 
-import javax.annotation.Nonnull;
 import java.util.List;
 
+import javax.annotation.Nonnull;
+
 /**
  * User: Solovyev_S
  * Date: 10.10.12
@@ -62,13 +63,13 @@ public class CalculatorHistoryTest {
         addState(calculatorHistory, "2354");
         addState(calculatorHistory, "23547");
 
-        final List<HistoryState> states = calculatorHistory.getCurrentHistory();
+        final List<HistoryState> states = calculatorHistory.getCurrent();
         Assert.assertEquals(2, states.size());
-        Assert.assertEquals("23547", states.get(1).getEditor().getTextString());
+        Assert.assertEquals("23547", states.get(1).editor.getTextString());
-        Assert.assertEquals("123+3", states.get(0).getEditor().getTextString());
+        Assert.assertEquals("123+3", states.get(0).editor.getTextString());
     }
 
     private void addState(@Nonnull CalculatorHistory calculatorHistory, @Nonnull String text) {
-        calculatorHistory.addCurrentState(HistoryState.newBuilder(EditorState.create(text, 3), DisplayState.empty()));
+        calculatorHistory.addCurrent(HistoryState.newBuilder(EditorState.create(text, 3), DisplayState.empty()));
     }
 }