From 13e7a5f9fe25b64b348ce7e0dae340abda93d5f4 Mon Sep 17 00:00:00 2001
From: serso <se.solovyev@gmail.com>
Date: Sun, 10 Apr 2016 23:26:55 +0200
Subject: [PATCH 1/5] Add E button to EditVariableFragment

---
 .../android/calculator/EditorView.java        |  9 ------
 .../variables/EditVariableFragment.java       | 31 +++++++++++++++++-
 .../calculator/view/EditTextCompat.java       |  9 ++----
 .../res/layout/fragment_variable_edit.xml     | 32 +++++++++++++++----
 .../main/res/values/text_non_translatable.xml |  2 ++
 app/src/main/res/values/text_strings.xml      |  1 -
 6 files changed, 59 insertions(+), 25 deletions(-)

diff --git a/app/src/main/java/org/solovyev/android/calculator/EditorView.java b/app/src/main/java/org/solovyev/android/calculator/EditorView.java
index 685eabef..2f928218 100644
--- a/app/src/main/java/org/solovyev/android/calculator/EditorView.java
+++ b/app/src/main/java/org/solovyev/android/calculator/EditorView.java
@@ -22,14 +22,11 @@
 
 package org.solovyev.android.calculator;
 
-import android.annotation.TargetApi;
 import android.content.Context;
-import android.os.Build;
 import android.text.Editable;
 import android.text.TextWatcher;
 import android.util.AttributeSet;
 import android.view.ContextMenu;
-
 import org.solovyev.android.Check;
 import org.solovyev.android.calculator.view.EditTextCompat;
 import org.solovyev.android.views.Adjuster;
@@ -58,12 +55,6 @@ public class EditorView extends EditTextCompat {
         init();
     }
 
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
-    public EditorView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
-        super(context, attrs, defStyleAttr, defStyleRes);
-        init();
-    }
-
     private void init() {
         if (!App.isFloatingCalculator(getContext())) {
             Adjuster.adjustText(this, 0.22f,
diff --git a/app/src/main/java/org/solovyev/android/calculator/variables/EditVariableFragment.java b/app/src/main/java/org/solovyev/android/calculator/variables/EditVariableFragment.java
index 79c4e738..a7ac1257 100644
--- a/app/src/main/java/org/solovyev/android/calculator/variables/EditVariableFragment.java
+++ b/app/src/main/java/org/solovyev/android/calculator/variables/EditVariableFragment.java
@@ -34,6 +34,9 @@ import android.support.design.widget.TextInputLayout;
 import android.support.v4.app.FragmentActivity;
 import android.support.v4.app.FragmentManager;
 import android.support.v7.app.AlertDialog;
+import android.text.Editable;
+import android.text.InputFilter;
+import android.text.SpannableStringBuilder;
 import android.view.KeyEvent;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -45,10 +48,11 @@ import android.widget.PopupWindow;
 import butterknife.Bind;
 import butterknife.ButterKnife;
 import dagger.Lazy;
+import jscl.JsclMathEngine;
 import jscl.math.function.IConstant;
+import midpcalc.Real;
 import org.solovyev.android.Check;
 import org.solovyev.android.calculator.*;
-import org.solovyev.android.calculator.RemovalConfirmationDialog;
 import org.solovyev.android.calculator.functions.FunctionsRegistry;
 import org.solovyev.android.calculator.keyboard.FloatingKeyboard;
 import org.solovyev.android.calculator.keyboard.FloatingKeyboardWindow;
@@ -87,6 +91,8 @@ public class EditVariableFragment extends BaseDialogFragment implements View.OnF
     TextInputLayout valueLabel;
     @Bind(R.id.variable_value)
     EditText valueView;
+    @Bind(R.id.variable_exponent_button)
+    Button exponentButton;
     @Bind(R.id.variable_description)
     EditText descriptionView;
     @Inject
@@ -304,6 +310,13 @@ public class EditVariableFragment extends BaseDialogFragment implements View.OnF
         nameView.setOnFocusChangeListener(this);
         nameView.setOnKeyListener(this);
         valueView.setOnFocusChangeListener(this);
+        valueView.setEditableFactory(new Editable.Factory() {
+            @Override
+            public Editable newEditable(CharSequence source) {
+                return new NoFiltersEditable(source);
+            }
+        });
+        exponentButton.setOnClickListener(this);
         descriptionView.setOnFocusChangeListener(this);
         keyboardButton.setOnClickListener(this);
 
@@ -352,6 +365,11 @@ public class EditVariableFragment extends BaseDialogFragment implements View.OnF
                     showKeyboard();
                 }
                 break;
+            case R.id.variable_exponent_button:
+                final int start = Math.max(valueView.getSelectionStart(), 0);
+                final int end = Math.max(valueView.getSelectionEnd(), 0);
+                valueView.getText().replace(Math.min(start, end), Math.max(start, end), "E", 0, 1);
+                break;
             default:
                 super.onClick(v);
                 break;
@@ -379,6 +397,17 @@ public class EditVariableFragment extends BaseDialogFragment implements View.OnF
         keyboardWindow.show(new GreekFloatingKeyboard(keyboardUser), getDialog());
     }
 
+    private static class NoFiltersEditable extends SpannableStringBuilder {
+        public NoFiltersEditable(CharSequence source) {
+            super(source);
+        }
+
+        @Override
+        public void setFilters(InputFilter[] filters) {
+            // we don't want filters as we want to support numbers in scientific notation
+        }
+    }
+
     private class KeyboardUser implements FloatingKeyboard.User {
         @NonNull
         @Override
diff --git a/app/src/main/java/org/solovyev/android/calculator/view/EditTextCompat.java b/app/src/main/java/org/solovyev/android/calculator/view/EditTextCompat.java
index 79f393b6..81a52e2a 100644
--- a/app/src/main/java/org/solovyev/android/calculator/view/EditTextCompat.java
+++ b/app/src/main/java/org/solovyev/android/calculator/view/EditTextCompat.java
@@ -1,8 +1,8 @@
 package org.solovyev.android.calculator.view;
 
-import android.annotation.TargetApi;
 import android.content.Context;
 import android.os.Build;
+import android.support.design.widget.TextInputEditText;
 import android.text.InputType;
 import android.util.AttributeSet;
 import android.util.Log;
@@ -12,7 +12,7 @@ import org.solovyev.android.Check;
 import javax.annotation.Nullable;
 import java.lang.reflect.Method;
 
-public class EditTextCompat extends EditText {
+public class EditTextCompat extends TextInputEditText {
 
     @Nullable
     private static Method setShowSoftInputOnFocusMethod;
@@ -30,11 +30,6 @@ public class EditTextCompat extends EditText {
         super(context, attrs, defStyleAttr);
     }
 
-    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
-    public EditTextCompat(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
-        super(context, attrs, defStyleAttr, defStyleRes);
-    }
-
     public void dontShowSoftInputOnFocusCompat() {
         setShowSoftInputOnFocusCompat(false);
     }
diff --git a/app/src/main/res/layout/fragment_variable_edit.xml b/app/src/main/res/layout/fragment_variable_edit.xml
index 7c39891e..26b9ce45 100644
--- a/app/src/main/res/layout/fragment_variable_edit.xml
+++ b/app/src/main/res/layout/fragment_variable_edit.xml
@@ -65,18 +65,36 @@
                 tools:ignore="UnusedAttribute" />
         </FrameLayout>
 
-        <android.support.design.widget.TextInputLayout
-            a:id="@+id/variable_value_label"
+        <FrameLayout
             a:layout_width="match_parent"
             a:layout_height="wrap_content">
 
-            <org.solovyev.android.calculator.view.EditTextCompat
-                a:id="@+id/variable_value"
+            <android.support.design.widget.TextInputLayout
+                a:id="@+id/variable_value_label"
                 a:layout_width="match_parent"
+                a:layout_height="wrap_content">
+
+                <EditText
+                    a:id="@+id/variable_value"
+                    a:layout_width="match_parent"
+                    a:layout_height="wrap_content"
+                    a:hint="@string/c_var_value"
+                    a:inputType="numberDecimal|numberSigned" />
+            </android.support.design.widget.TextInputLayout>
+
+            <Button
+                a:id="@+id/variable_exponent_button"
+                a:layout_width="wrap_content"
                 a:layout_height="wrap_content"
-                a:hint="@string/c_var_value"
-                a:inputType="numberDecimal|numberSigned" />
-        </android.support.design.widget.TextInputLayout>
+                a:layout_gravity="end|top"
+                a:background="?attr/selectableItemBackgroundBorderless"
+                a:minWidth="0dp"
+                a:padding="@dimen/cpp_image_button_padding"
+                a:text="@string/cpp_exponent"
+                a:textAllCaps="false"
+                a:textAppearance="?android:attr/textAppearanceSmall"
+                tools:ignore="UnusedAttribute" />
+        </FrameLayout>
 
         <android.support.design.widget.TextInputLayout
             a:layout_width="match_parent"
diff --git a/app/src/main/res/values/text_non_translatable.xml b/app/src/main/res/values/text_non_translatable.xml
index 7d042a83..9e49f240 100644
--- a/app/src/main/res/values/text_non_translatable.xml
+++ b/app/src/main/res/values/text_non_translatable.xml
@@ -14,6 +14,8 @@
     <string name="dimensions_y_min" translatable="false">Y min</string>
     <string name="dimensions_y_max" translatable="false">Y max</string>
     <string name="cpp_function_body" translatable="false">f(x, y)</string>
+    <string name="cpp_show_greek_keyboard" translatable="false">αβγ</string>
+    <string name="cpp_exponent" translatable="false">E</string>
     <string-array name="cpp_prefs_precisions" translatable="false">
         <item>0</item>
         <item>1</item>
diff --git a/app/src/main/res/values/text_strings.xml b/app/src/main/res/values/text_strings.xml
index 27f9623d..45c92675 100644
--- a/app/src/main/res/values/text_strings.xml
+++ b/app/src/main/res/values/text_strings.xml
@@ -115,7 +115,6 @@
 		several devices.\n\n
 		By clicking \'Continue\' button you will be redirected to the Google Play app to make the payment.</string>
     <string name="cpp_purchase_title">Purchase</string>
-    <string name="cpp_show_greek_keyboard" translatable="false">αβγ</string>
     <string name="cpp_clear_history_title">Clear history?</string>
     <string name="cpp_clear_history_message">All history will be cleared.</string>
     <string name="cpp_clear_history">Clear</string>

From c51f3043bca71fd4d4b0c30d51c6ba58b20ab885 Mon Sep 17 00:00:00 2001
From: serso <se.solovyev@gmail.com>
Date: Sun, 10 Apr 2016 23:58:19 +0200
Subject: [PATCH 2/5] New release notes

---
 .../calculator/release/ReleaseNotes.java      | 16 +++++---
 .../main/res/values-ru/text_release_notes.xml | 37 +++++++++--------
 .../main/res/values/text_release_notes.xml    | 41 ++++++++++---------
 3 files changed, 50 insertions(+), 44 deletions(-)

diff --git a/app/src/main/java/org/solovyev/android/calculator/release/ReleaseNotes.java b/app/src/main/java/org/solovyev/android/calculator/release/ReleaseNotes.java
index 6f0aa6d4..5b45e3f1 100644
--- a/app/src/main/java/org/solovyev/android/calculator/release/ReleaseNotes.java
+++ b/app/src/main/java/org/solovyev/android/calculator/release/ReleaseNotes.java
@@ -14,9 +14,9 @@ public final class ReleaseNotes {
 
     private static final SparseArray<ReleaseNote> map = new SparseArray<>();
     static {
-        map.put(118, ReleaseNote.make("2.0.0", R.string.c_release_notes_for_118));
-        map.put(141, ReleaseNote.make("2.1.2", R.string.c_release_notes_for_141));
-        map.put(143, ReleaseNote.make("2.1.4", R.string.c_release_notes_for_143));
+        map.put(141, ReleaseNote.make("2.1.2", R.string.cpp_release_notes_141));
+        map.put(143, ReleaseNote.make("2.1.4", R.string.cpp_release_notes_143));
+        map.put(148, ReleaseNote.make("2.2.1", R.string.cpp_release_notes_148));
     }
 
     @Nonnull
@@ -33,7 +33,7 @@ public final class ReleaseNotes {
     @Nonnull
     public static String getReleaseNoteDescription(@Nonnull Context context, int version) {
         final ReleaseNote releaseNote = map.get(version);
-        return releaseNote == null ? "" : context.getString(releaseNote.description);
+        return releaseNote == null ? "" : getDescription(context, releaseNote.description);
     }
 
     @Nonnull
@@ -54,8 +54,7 @@ public final class ReleaseNotes {
             } else {
                 first = false;
             }
-            final String description = context.getResources().getString(releaseNote.description);
-            final String descriptionHtml = description.replace("\n", "<br/>");
+            final String descriptionHtml = getDescription(context, releaseNote.description);
             result.append("<b>").append(releaseNotesForTitle).append(releaseNote.versionName).append("</b><br/><br/>");
             result.append(descriptionHtml);
         }
@@ -63,6 +62,11 @@ public final class ReleaseNotes {
         return result.toString();
     }
 
+    @Nonnull
+    private static String getDescription(@Nonnull Context context, int description) {
+        return context.getResources().getString(description).replace("\n", "<br/>");
+    }
+
     @Nonnull
     public static List<Integer> getReleaseNotesVersions(@Nonnull Context context, int minVersion) {
         final List<Integer> releaseNotes = new ArrayList<>();
diff --git a/app/src/main/res/values-ru/text_release_notes.xml b/app/src/main/res/values-ru/text_release_notes.xml
index c283d4c8..5b8beca5 100644
--- a/app/src/main/res/values-ru/text_release_notes.xml
+++ b/app/src/main/res/values-ru/text_release_notes.xml
@@ -22,25 +22,26 @@
 
 <resources>
 
-	<string name="c_release_notes_for_118">
-		★ Немецкий и польский языки\n
-		★ Визард\n
-		★ Улучшения графопостроителя\n
-		★ Исправлена пролема с Asin(i)\n
-		★ Греческие буквы для названий переменных\n
-		★ Другие исправления и улучшения
-	</string>
+    <string name="cpp_release_notes_141">
+        ★ Улучшен ввод жестами\n
+        ★ Быстрое удаление текста при долгом нажатии кнопки "Удалить"\n
+        ★ Кнопка "Равно" копирует результат в поле ввода
+    </string>
 
-	<string name="c_release_notes_for_141">
-		★ Улучшен ввод жестами\n
-		★ Быстрое удаление текста при долгом нажатии кнопки "Удалить"\n
-		★ Кнопка "Равно" копирует результат в поле ввода
-	</string>
+    <string name="cpp_release_notes_143">
+        ★ Язык приложения может быть изменён в настройках\n
+        ★ Темы для калькулятора в отдельном окне\n
+        ★ Темы для виджета на рабочий стол
+    </string>
 
-	<string name="c_release_notes_for_143">
-		★ Язык приложения может быть изменён в настройках\n
-		★ Темы для калькулятора в отдельном окне\n
-		★ Темы для виджета на рабочий стол
-	</string>
+    <string name="cpp_release_notes_148">
+        ★ Новый графопостроитель\n
+        ★ Улучшенный пользовательский интерфейс: главный и второстепенные экраны, диалоги, меню и т.д.\n
+        ★ Переделанный переводчик величин\n
+        ★ Кнопка Память (MC, M+, M-, M)\n
+        ★ Плавающий калькулятор для Андроид М\n
+        ★ Автосохранение недавней истории\n
+        ★ Приложение быстрее запускается и потребляет меньше памяти
+    </string>
 
 </resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/text_release_notes.xml b/app/src/main/res/values/text_release_notes.xml
index f92abb35..f2e5614d 100644
--- a/app/src/main/res/values/text_release_notes.xml
+++ b/app/src/main/res/values/text_release_notes.xml
@@ -22,27 +22,28 @@
 
 <resources xmlns:tools="http://schemas.android.com/tools" tools:ignore="MissingTranslation">
 
-	<string name="c_release_notes_for_118">
-		★ German and Polish translations\n
-		★ Wizard\n
-		★ Graph improvements\n
-		★ Asin(i) problem fix\n
-		★ Greek letters for variable names\n
-		★ Other fixes
-	</string>
+    <string name="cpp_release_notes_141">
+        ★ Improved button gesture detection\n
+        ★ Fast text removal by long pressing "Erase" button\n
+        ★ "Equals" button now copies result to the editor\n
+        ★ Various bugfixes, stability and usability improvements
+    </string>
 
-	<string name="c_release_notes_for_141">
-		★ Improved button gesture detection\n
-		★ Fast text removal by long pressing "Erase" button\n
-		★ "Equals" button now copies result to the editor\n
-		★ Various bugfixes, stability and usability improvements
-	</string>
+    <string name="cpp_release_notes_143">
+        ★ App language can be changed in settings\n
+        ★ Floating calculator themes\n
+        ★ Widget themes\n
+        ★ Various bugfixes, stability and usability improvements
+    </string>
 
-	<string name="c_release_notes_for_143">
-		★ App language can be changed in settings\n
-		★ Floating calculator themes\n
-		★ Widget themes\n
-		★ Various bugfixes, stability and usability improvements
-	</string>
+    <string name="cpp_release_notes_148">
+        ★ New graph plotter\n
+        ★ Improved user interface: main and additional screens, dialogs, menus, etc\n
+        ★ Redesigned unit converter\n
+        ★ Memory button (MC, M+, M-, M)\n
+        ★ Floating calculator for Android M\n
+        ★ Auto-save of recent history\n
+        ★ Faster start-ups, less memory consumption
+    </string>
 
 </resources>
\ No newline at end of file

From 6c6d66caf7cb472f76e83a8d2b5ce4e3e1b33186 Mon Sep 17 00:00:00 2001
From: serso <se.solovyev@gmail.com>
Date: Sun, 10 Apr 2016 23:58:45 +0200
Subject: [PATCH 3/5] Version bump

---
 app/build.gradle | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/app/build.gradle b/app/build.gradle
index 399b14a0..8be66346 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -31,8 +31,8 @@ android {
     defaultConfig {
         minSdkVersion 9
         targetSdkVersion 23
-        versionCode 147
-        versionName '2.2.0'
+        versionCode 148
+        versionName '2.2.1'
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
         generatedDensities = []
     }

From 6c23fa2cb6e7eca2ea059912bd15e966b9c883fa Mon Sep 17 00:00:00 2001
From: serso <se.solovyev@gmail.com>
Date: Mon, 11 Apr 2016 12:58:59 +0200
Subject: [PATCH 4/5] Android Studio 2

---
 build.gradle                             | 2 +-
 gradle/wrapper/gradle-wrapper.properties | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/build.gradle b/build.gradle
index 5cf65e50..b4afb145 100644
--- a/build.gradle
+++ b/build.gradle
@@ -3,7 +3,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:1.5.0'
+        classpath 'com.android.tools.build:gradle:2.0.0'
         classpath 'com.neenbedankt.gradle.plugins:android-apt:1.4'
     }
 }
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 8c2ac5ed..6f6c2b88 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,6 @@
-#Mon Jan 04 12:04:44 CET 2016
+#Mon Apr 11 12:52:10 CEST 2016
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.10-all.zip

From a7c2d0b2e25fb06aa15c10c344e2ef71e75d1745 Mon Sep 17 00:00:00 2001
From: serso <se.solovyev@gmail.com>
Date: Mon, 11 Apr 2016 22:08:06 +0200
Subject: [PATCH 5/5] Exponent in EditVariableFragment

---
 .../variables/EditVariableFragment.java       |  10 +-
 .../text/method/NumberInputFilter.java        | 176 ++++++++++++++++++
 2 files changed, 181 insertions(+), 5 deletions(-)
 create mode 100644 app/src/main/java/org/solovyev/android/text/method/NumberInputFilter.java

diff --git a/app/src/main/java/org/solovyev/android/calculator/variables/EditVariableFragment.java b/app/src/main/java/org/solovyev/android/calculator/variables/EditVariableFragment.java
index a7ac1257..6170e276 100644
--- a/app/src/main/java/org/solovyev/android/calculator/variables/EditVariableFragment.java
+++ b/app/src/main/java/org/solovyev/android/calculator/variables/EditVariableFragment.java
@@ -48,9 +48,7 @@ import android.widget.PopupWindow;
 import butterknife.Bind;
 import butterknife.ButterKnife;
 import dagger.Lazy;
-import jscl.JsclMathEngine;
 import jscl.math.function.IConstant;
-import midpcalc.Real;
 import org.solovyev.android.Check;
 import org.solovyev.android.calculator.*;
 import org.solovyev.android.calculator.functions.FunctionsRegistry;
@@ -58,6 +56,7 @@ import org.solovyev.android.calculator.keyboard.FloatingKeyboard;
 import org.solovyev.android.calculator.keyboard.FloatingKeyboardWindow;
 import org.solovyev.android.calculator.math.MathType;
 import org.solovyev.android.calculator.view.EditTextCompat;
+import org.solovyev.android.text.method.NumberInputFilter;
 import org.solovyev.common.text.Strings;
 
 import javax.annotation.Nonnull;
@@ -313,7 +312,7 @@ public class EditVariableFragment extends BaseDialogFragment implements View.OnF
         valueView.setEditableFactory(new Editable.Factory() {
             @Override
             public Editable newEditable(CharSequence source) {
-                return new NoFiltersEditable(source);
+                return new NumberEditable(source);
             }
         });
         exponentButton.setOnClickListener(this);
@@ -397,9 +396,10 @@ public class EditVariableFragment extends BaseDialogFragment implements View.OnF
         keyboardWindow.show(new GreekFloatingKeyboard(keyboardUser), getDialog());
     }
 
-    private static class NoFiltersEditable extends SpannableStringBuilder {
-        public NoFiltersEditable(CharSequence source) {
+    private static class NumberEditable extends SpannableStringBuilder {
+        public NumberEditable(CharSequence source) {
             super(source);
+            super.setFilters(new InputFilter[]{NumberInputFilter.getInstance()});
         }
 
         @Override
diff --git a/app/src/main/java/org/solovyev/android/text/method/NumberInputFilter.java b/app/src/main/java/org/solovyev/android/text/method/NumberInputFilter.java
new file mode 100644
index 00000000..5600c096
--- /dev/null
+++ b/app/src/main/java/org/solovyev/android/text/method/NumberInputFilter.java
@@ -0,0 +1,176 @@
+package org.solovyev.android.text.method;
+
+import android.support.annotation.NonNull;
+import android.support.annotation.Nullable;
+import android.text.InputFilter;
+import android.text.SpannableStringBuilder;
+import android.text.Spanned;
+
+public class NumberInputFilter implements InputFilter {
+
+    private static final int[] CHARS = new int[]{-1, -1, -1};
+    private static final int CHAR_SIGN = 0;
+    private static final int CHAR_POINT = 1;
+    private static final int CHAR_EXP = 2;
+
+    private static final char[] ACCEPTED = {'E', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-', '+', '.'};
+    private static final NumberInputFilter INSTANCE = new NumberInputFilter();
+
+    private static boolean isSignChar(final char c) {
+        return c == '-' || c == '+';
+    }
+
+    private static boolean isDecimalPointChar(final char c) {
+        return c == '.';
+    }
+
+    private static boolean isExponentChar(final char c) {
+        return c == 'E';
+    }
+
+    /**
+     * Returns a NumberInputFilter that accepts the digits 0 through 9.
+     */
+    public static NumberInputFilter getInstance() {
+        return INSTANCE;
+    }
+
+    private static boolean accepted(char c) {
+        for (int i = ACCEPTED.length - 1; i >= 0; i--) {
+            if (ACCEPTED[i] == c) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
+    public CharSequence filter(CharSequence source, int start, int end,
+                               Spanned dest, int dstart, int dend) {
+        final CharSequence out = filterIllegalCharacters(source, start, end);
+        if (out != null) {
+            source = out;
+            start = 0;
+            end = out.length();
+        }
+
+        CHARS[CHAR_SIGN] = -1;
+        CHARS[CHAR_POINT] = -1;
+        CHARS[CHAR_EXP] = -1;
+        findChars(dest, 0, dstart, 0, CHARS);
+        findChars(dest, dend, dest.length(), end - start, CHARS);
+
+        SpannableStringBuilder filtered = null;
+        for (int i = end - 1; i >= start; i--) {
+            final char c = source.charAt(i);
+
+            boolean filter = false;
+            if (isSignChar(c)) {
+                if (i == start && dstart == 0) {
+                    if (CHARS[CHAR_SIGN] >= 0) {
+                        filter = true;
+                    } else {
+                        CHARS[CHAR_SIGN] = i + dstart;
+                    }
+                } else if (CHARS[CHAR_EXP] == i + dstart - 1) {
+                    // allow sign after exponent symbol
+                    filter = false;
+                } else {
+                    filter = true;
+                }
+            } else if (isDecimalPointChar(c)) {
+                if (CHARS[CHAR_POINT] >= 0) {
+                    filter = true;
+                } else if (CHARS[CHAR_EXP] >= 0 && CHARS[CHAR_EXP] < i + dstart) {
+                    // no decimal point after exponent
+                    filter = true;
+                } else {
+                    CHARS[CHAR_POINT] = i + dstart;
+                }
+            } else if (isExponentChar(c)) {
+                if (CHARS[CHAR_EXP] >= 0) {
+                    filter = true;
+                } else if (CHARS[CHAR_POINT] >= 0 && CHARS[CHAR_POINT] > i + dstart) {
+                    // no exponent before decimal point
+                    filter = true;
+                } else {
+                    CHARS[CHAR_EXP] = i + dstart;
+                }
+            }
+
+            if (filter) {
+                if (end == start + 1) {
+                    return "";  // Only one character, and it was stripped.
+                }
+
+                if (filtered == null) {
+                    filtered = new SpannableStringBuilder(source, start, end);
+                }
+
+                filtered.delete(i - start, i + 1 - start);
+            }
+        }
+
+        if (filtered != null) {
+            return filtered;
+        } else if (out != null) {
+            return out;
+        } else {
+            return null;
+        }
+    }
+
+    private void findChars(@NonNull Spanned s, int start, int end, int offset, int[] out) {
+        for (int i = start; i < end; i++) {
+            final char c = s.charAt(i);
+
+            if (isSignChar(c)) {
+                if (out[CHAR_SIGN] == -1 && out[CHAR_EXP] == -1) {
+                    // count in only signs before exponent
+                    out[CHAR_SIGN] = i + offset;
+                }
+            } else if (isDecimalPointChar(c)) {
+                if (out[CHAR_POINT] == -1) {
+                    out[CHAR_POINT] = i + offset;
+                }
+            } else if (isExponentChar(c)) {
+                if (out[CHAR_EXP] == -1) {
+                    out[CHAR_EXP] = i + offset;
+                }
+            }
+        }
+    }
+
+    @Nullable
+    private CharSequence filterIllegalCharacters(CharSequence source, int start, int end) {
+        final int illegal = findIllegalChar(source, start, end);
+        if (illegal == end) {
+            // all OK
+            return null;
+        }
+        if (end - start == 1) {
+            // it was not OK, and there is only one char, so nothing remains.
+            return "";
+        }
+
+        final SpannableStringBuilder filtered = new SpannableStringBuilder(source, start, end);
+        final int newEnd = end - start - 1;
+        // only count down to "illegal" because the chars before that were all OK.
+        final int newIllegal = illegal - start;
+        for (int j = newEnd; j >= newIllegal; j--) {
+            if (!accepted(source.charAt(j))) {
+                filtered.delete(j, j + 1);
+            }
+        }
+        return filtered;
+    }
+
+    private int findIllegalChar(CharSequence s, int start, int end) {
+        for (int i = start; i < end; i++) {
+            if (!accepted(s.charAt(i))) {
+                return i;
+            }
+        }
+        return end;
+    }
+}