diff --git a/.gitignore b/.gitignore
index 446ed0d..c1f17b0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,3 +8,5 @@ build/
 ios/.generated/
 ios/Flutter/Generated.xcconfig
 ios/Runner/GeneratedPluginRegistrant.*
+
+.idea/**
diff --git a/.idea/libraries/Dart_Packages.xml b/.idea/libraries/Dart_Packages.xml
index 51db6e8..a7102d6 100644
--- a/.idea/libraries/Dart_Packages.xml
+++ b/.idea/libraries/Dart_Packages.xml
@@ -5,174 +5,182 @@
         <entry key="async">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/async-2.4.1/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/async-2.5.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="boolean_selector">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/boolean_selector-2.0.0/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/boolean_selector-2.1.0-nullsafety.1/lib" />
+            </list>
+          </value>
+        </entry>
+        <entry key="characters">
+          <value>
+            <list>
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/characters-1.1.0-nullsafety.3/lib" />
             </list>
           </value>
         </entry>
         <entry key="charcode">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/charcode-1.1.3/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/charcode-1.2.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="clock">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/clock-1.0.1/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/clock-1.1.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="collection">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/collection-1.14.12/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/collection-1.15.0-nullsafety.3/lib" />
             </list>
           </value>
         </entry>
         <entry key="cupertino_icons">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/cupertino_icons-0.1.3/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/cupertino_icons-0.1.3/lib" />
             </list>
           </value>
         </entry>
         <entry key="fake_async">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/fake_async-1.1.0/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/fake_async-1.2.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="flutter">
           <value>
             <list>
-              <option value="$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/packages/flutter/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/packages/flutter/lib" />
             </list>
           </value>
         </entry>
         <entry key="flutter_test">
           <value>
             <list>
-              <option value="$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/packages/flutter_test/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/packages/flutter_test/lib" />
             </list>
           </value>
         </entry>
         <entry key="matcher">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/matcher-0.12.6/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/matcher-0.12.10-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="meta">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/meta-1.1.8/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.3/lib" />
             </list>
           </value>
         </entry>
         <entry key="path">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/path-1.7.0/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="sky_engine">
           <value>
             <list>
-              <option value="$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/pkg/sky_engine/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/bin/cache/pkg/sky_engine/lib" />
             </list>
           </value>
         </entry>
         <entry key="source_span">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/source_span-1.7.0/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/source_span-1.8.0-nullsafety.2/lib" />
             </list>
           </value>
         </entry>
         <entry key="stack_trace">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/stack_trace-1.9.3/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/stack_trace-1.10.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="stream_channel">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/stream_channel-2.0.0/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/stream_channel-2.1.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="string_scanner">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/string_scanner-1.0.5/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/string_scanner-1.1.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="term_glyph">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/term_glyph-1.1.0/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/term_glyph-1.2.0-nullsafety.1/lib" />
             </list>
           </value>
         </entry>
         <entry key="test_api">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/test_api-0.2.16/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/test_api-0.2.19-nullsafety.2/lib" />
             </list>
           </value>
         </entry>
         <entry key="typed_data">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/typed_data-1.1.6/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/typed_data-1.3.0-nullsafety.3/lib" />
             </list>
           </value>
         </entry>
         <entry key="vector_math">
           <value>
             <list>
-              <option value="$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/vector_math-2.0.8/lib" />
+              <option value="$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/vector_math-2.1.0-nullsafety.3/lib" />
             </list>
           </value>
         </entry>
       </option>
     </properties>
     <CLASSES>
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/async-2.4.1/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/boolean_selector-2.0.0/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/charcode-1.1.3/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/clock-1.0.1/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/collection-1.14.12/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/cupertino_icons-0.1.3/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/fake_async-1.1.0/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/matcher-0.12.6/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/meta-1.1.8/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/path-1.7.0/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/source_span-1.7.0/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/stack_trace-1.9.3/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/stream_channel-2.0.0/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/string_scanner-1.0.5/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/term_glyph-1.1.0/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/test_api-0.2.16/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/typed_data-1.1.6/lib" />
-      <root url="file://$USER_HOME$/AppData/Local/Pub/Cache/hosted/pub.dartlang.org/vector_math-2.0.8/lib" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/pkg/sky_engine/lib" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/packages/flutter/lib" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/packages/flutter_test/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/async-2.5.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/boolean_selector-2.1.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/characters-1.1.0-nullsafety.3/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/charcode-1.2.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/clock-1.1.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/collection-1.15.0-nullsafety.3/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/cupertino_icons-0.1.3/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/fake_async-1.2.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/matcher-0.12.10-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/meta-1.3.0-nullsafety.3/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/path-1.8.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/source_span-1.8.0-nullsafety.2/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/stack_trace-1.10.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/stream_channel-2.1.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/string_scanner-1.1.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/term_glyph-1.2.0-nullsafety.1/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/test_api-0.2.19-nullsafety.2/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/typed_data-1.3.0-nullsafety.3/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/.pub-cache/hosted/pub.dartlang.org/vector_math-2.1.0-nullsafety.3/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/pkg/sky_engine/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/packages/flutter/lib" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/packages/flutter_test/lib" />
     </CLASSES>
     <JAVADOC />
     <SOURCES />
diff --git a/.idea/libraries/Dart_SDK.xml b/.idea/libraries/Dart_SDK.xml
index 22ebdc2..3aeef26 100644
--- a/.idea/libraries/Dart_SDK.xml
+++ b/.idea/libraries/Dart_SDK.xml
@@ -1,27 +1,27 @@
 <component name="libraryTable">
   <library name="Dart SDK">
     <CLASSES>
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/async" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/cli" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/collection" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/convert" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/core" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/developer" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/ffi" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/html" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/indexed_db" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/io" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/isolate" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/js" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/js_util" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/math" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/mirrors" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/svg" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/typed_data" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/wasm" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/web_audio" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/web_gl" />
-      <root url="file://$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin/cache/dart-sdk/lib/web_sql" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/async" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/cli" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/collection" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/convert" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/core" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/developer" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/ffi" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/html" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/indexed_db" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/io" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/isolate" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/js" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/js_util" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/math" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/mirrors" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/svg" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/typed_data" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/wasm" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/web_audio" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/web_gl" />
+      <root url="file://$USER_HOME$/snap/flutter/common/flutter/bin/cache/dart-sdk/lib/web_sql" />
     </CLASSES>
     <JAVADOC />
     <SOURCES />
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index b646b67..b980615 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -18,9 +18,8 @@
   </component>
   <component name="ChangeListManager">
     <list default="true" id="454e3a70-107c-46fa-b354-df0efe7224c0" name="Default" comment="## [1.7.0]&#10;* Added `hasUnderline` option in pin box.">
+      <change beforePath="$PROJECT_DIR$/.gitignore" beforeDir="false" afterPath="$PROJECT_DIR$/.gitignore" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/lib/pin_code_text_field.dart" beforeDir="false" afterPath="$PROJECT_DIR$/lib/pin_code_text_field.dart" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/pubspec.yaml" beforeDir="false" afterPath="$PROJECT_DIR$/pubspec.yaml" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -30,7 +29,6 @@
   <component name="DefaultGradleProjectSettings">
     <option name="isMigrated" value="true" />
   </component>
-  <component name="ExecutionTargetManager" SELECTED_TARGET="device_and_snapshot_combo_box_target[1c92034c2b037ece]" />
   <component name="Git.Settings">
     <option name="RECENT_GIT_ROOT_PATH" value="$PROJECT_DIR$" />
     <option name="RECENT_BRANCH_BY_REPOSITORY">
@@ -57,7 +55,7 @@
     <property name="dart.analysis.tool.window.force.activate" value="false" />
     <property name="dart.analysis.tool.window.visible" value="false" />
     <property name="io.flutter.reload.alreadyRun" value="true" />
-    <property name="last_opened_file_path" value="$USER_HOME$/Documents/Application/flutter_windows_1.17.1-stable/flutter/bin" />
+    <property name="last_opened_file_path" value="$PROJECT_DIR$" />
     <property name="project.structure.last.edited" value="Project" />
     <property name="project.structure.proportion" value="0.15" />
     <property name="project.structure.side.proportion" value="0.0" />
@@ -363,22 +361,10 @@
     <option name="LAST_COMMIT_MESSAGE" value="## [1.7.0]&#10;* Added `hasUnderline` option in pin box." />
   </component>
   <component name="WindowStateProjectService">
-    <state x="910" y="572" width="985" height="763" key="CommitChangelistDialog2" timestamp="1597740387044">
-      <screen x="0" y="0" width="2560" height="1400" />
+    <state x="2579" y="259" width="672" height="678" key="search.everywhere.popup" timestamp="1607026862231">
+      <screen x="1920" y="0" width="1920" height="1080" />
     </state>
-    <state x="910" y="572" width="985" height="763" key="CommitChangelistDialog2/0.0.2560.1400/-1920.940.1920.1040@0.0.2560.1400" timestamp="1597740387044" />
-    <state x="1388" y="633" key="FileChooserDialogImpl" timestamp="1597740121557">
-      <screen x="0" y="0" width="2560" height="1400" />
-    </state>
-    <state x="1388" y="633" key="FileChooserDialogImpl/0.0.2560.1400/-1920.940.1920.1040@0.0.2560.1400" timestamp="1597740121557" />
-    <state x="703" y="456" key="SettingsEditor" timestamp="1597740136909">
-      <screen x="0" y="0" width="2560" height="1400" />
-    </state>
-    <state x="703" y="456" key="SettingsEditor/0.0.2560.1400/-1920.940.1920.1040@0.0.2560.1400" timestamp="1597740136909" />
-    <state x="799" y="626" key="Vcs.Push.Dialog.v2" timestamp="1597740390808">
-      <screen x="0" y="0" width="2560" height="1400" />
-    </state>
-    <state x="799" y="626" key="Vcs.Push.Dialog.v2/0.0.2560.1400/-1920.940.1920.1040@0.0.2560.1400" timestamp="1597740390808" />
+    <state x="2579" y="259" width="672" height="678" key="search.everywhere.popup/1920.0.1920.1080/3840.0.3840.1080/0.27.1920.1053@1920.0.1920.1080" timestamp="1607026862231" />
   </component>
   <component name="masterDetails">
     <states>
diff --git a/example/ios/Flutter/flutter_export_environment.sh b/example/ios/Flutter/flutter_export_environment.sh
new file mode 100755
index 0000000..86f60fc
--- /dev/null
+++ b/example/ios/Flutter/flutter_export_environment.sh
@@ -0,0 +1,15 @@
+#!/bin/sh
+# This is a generated file; do not edit or check into version control.
+export "FLUTTER_ROOT=/home/felipe/snap/flutter/common/flutter"
+export "FLUTTER_APPLICATION_PATH=/home/felipe/Sources/pin_code_text_field/example"
+export "FLUTTER_TARGET=lib/main.dart"
+export "FLUTTER_BUILD_DIR=build"
+export "SYMROOT=${SOURCE_ROOT}/../build/ios"
+export "OTHER_LDFLAGS=$(inherited) -framework Flutter"
+export "FLUTTER_FRAMEWORK_DIR=/home/felipe/snap/flutter/common/flutter/bin/cache/artifacts/engine/ios"
+export "FLUTTER_BUILD_NAME=1.0.0"
+export "FLUTTER_BUILD_NUMBER=1"
+export "DART_OBFUSCATION=false"
+export "TRACK_WIDGET_CREATION=false"
+export "TREE_SHAKE_ICONS=false"
+export "PACKAGE_CONFIG=.packages"
diff --git a/lib/pin_code_text_field.dart b/lib/pin_code_text_field.dart
index 5989b69..445c577 100644
--- a/lib/pin_code_text_field.dart
+++ b/lib/pin_code_text_field.dart
@@ -6,6 +6,7 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
+import 'package:pin_code_text_field/upper-case-text-formatter.dart';
 
 typedef OnDone = void Function(String text);
 typedef PinBoxDecoration = BoxDecoration Function(
@@ -140,6 +141,7 @@ class PinCodeTextField extends StatefulWidget {
   final TextInputType keyboardType;
   final EdgeInsets pinBoxOuterPadding;
   final bool hasUnderline;
+  final bool upperCase;
 
   const PinCodeTextField({
     Key key,
@@ -178,6 +180,7 @@ class PinCodeTextField extends StatefulWidget {
     this.pinBoxRadius = 0,
     this.hideDefaultKeyboard = false,
     this.hasUnderline = false,
+    this.upperCase = false
   }) : super(key: key);
 
   @override
@@ -377,6 +380,7 @@ class PinCodeTextFieldState extends State<PinCodeTextField>
         keyboardType: widget.keyboardType,
         inputFormatters: widget.keyboardType == TextInputType.number
             ? <TextInputFormatter>[WhitelistingTextInputFormatter.digitsOnly]
+            : widget.upperCase ? [UpperCaseTextFormatter()]
             : null,
         style: TextStyle(
           height: 0.1, color: Colors.transparent,
@@ -417,6 +421,7 @@ class PinCodeTextFieldState extends State<PinCodeTextField>
         keyboardType: widget.keyboardType,
         inputFormatters: widget.keyboardType == TextInputType.number
             ? <TextInputFormatter>[WhitelistingTextInputFormatter.digitsOnly]
+            : widget.upperCase ? [UpperCaseTextFormatter()]
             : null,
         style: TextStyle(
           color: Colors.transparent,
diff --git a/lib/upper-case-text-formatter.dart b/lib/upper-case-text-formatter.dart
new file mode 100644
index 0000000..bffb77b
--- /dev/null
+++ b/lib/upper-case-text-formatter.dart
@@ -0,0 +1,13 @@
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
+
+class UpperCaseTextFormatter extends TextInputFormatter {
+  @override
+  TextEditingValue formatEditUpdate(
+      TextEditingValue oldValue, TextEditingValue newValue) {
+    return TextEditingValue(
+      text: newValue.text?.toUpperCase(),
+      selection: newValue.selection,
+    );
+  }
+}