diff --git a/.gitignore b/.gitignore
index e9dc58d..f328db6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,10 @@
 .pub/
 
 build/
+.idea
+.idea/.gitignore
+.idea/http_proxy.iml
+.idea/libraries/
+.idea/misc.xml
+.idea/modules.xml
+.idea/vcs.xml
diff --git a/android/build.gradle b/android/build.gradle
index a88fa8d..e181482 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -3,17 +3,27 @@ version '1.0'
 
 buildscript {
     repositories {
+        maven { url 'https://maven.aliyun.com/repository/google' }
+        maven { url 'https://maven.aliyun.com/repository/jcenter' }
+        maven { url 'https://maven.aliyun.com/repository/public' }
+        maven { url 'https://maven.aliyun.com/repository/gradle-plugin' }
+        mavenCentral()
         google()
         jcenter()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath 'com.android.tools.build:gradle:3.6.4'
     }
 }
 
 rootProject.allprojects {
     repositories {
+        maven { url 'https://maven.aliyun.com/repository/google' }
+        maven { url 'https://maven.aliyun.com/repository/jcenter' }
+        maven { url 'https://maven.aliyun.com/repository/public' }
+        maven { url 'https://maven.aliyun.com/repository/gradle-plugin' }
+        mavenCentral()
         google()
         jcenter()
     }
@@ -22,7 +32,7 @@ rootProject.allprojects {
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 28
+    compileSdkVersion 30
 
     defaultConfig {
         minSdkVersion 16
diff --git a/android/gradle/wrapper/gradle-wrapper.properties b/android/gradle/wrapper/gradle-wrapper.properties
index 01a286e..3c9d085 100644
--- a/android/gradle/wrapper/gradle-wrapper.properties
+++ b/android/gradle/wrapper/gradle-wrapper.properties
@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-all.zip
diff --git a/example/android/app/build.gradle b/example/android/app/build.gradle
index 1530d72..5dd5761 100644
--- a/example/android/app/build.gradle
+++ b/example/android/app/build.gradle
@@ -25,7 +25,7 @@ apply plugin: 'com.android.application'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 28
+    compileSdkVersion 30
 
     lintOptions {
         disable 'InvalidPackage'
@@ -35,7 +35,7 @@ android {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "com.lm.http_proxy_example"
         minSdkVersion 16
-        targetSdkVersion 28
+        targetSdkVersion 30
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
     }
diff --git a/example/android/build.gradle b/example/android/build.gradle
index e0d7ae2..62d6f64 100644
--- a/example/android/build.gradle
+++ b/example/android/build.gradle
@@ -1,16 +1,26 @@
 buildscript {
     repositories {
+        maven { url 'https://maven.aliyun.com/repository/google' }
+        maven { url 'https://maven.aliyun.com/repository/jcenter' }
+        maven { url 'https://maven.aliyun.com/repository/public' }
+        maven { url 'https://maven.aliyun.com/repository/gradle-plugin' }
+        mavenCentral()
         google()
         jcenter()
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath 'com.android.tools.build:gradle:3.6.4'
     }
 }
 
 allprojects {
     repositories {
+        maven { url 'https://maven.aliyun.com/repository/google' }
+        maven { url 'https://maven.aliyun.com/repository/jcenter' }
+        maven { url 'https://maven.aliyun.com/repository/public' }
+        maven { url 'https://maven.aliyun.com/repository/gradle-plugin' }
+        mavenCentral()
         google()
         jcenter()
     }
diff --git a/example/android/gradle/wrapper/gradle-wrapper.properties b/example/android/gradle/wrapper/gradle-wrapper.properties
index 296b146..bc6a58a 100644
--- a/example/android/gradle/wrapper/gradle-wrapper.properties
+++ b/example/android/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-all.zip
diff --git a/example/lib/main.dart b/example/lib/main.dart
index ac3fda9..1ba6e70 100644
--- a/example/lib/main.dart
+++ b/example/lib/main.dart
@@ -29,12 +29,12 @@ class MyApp extends StatefulWidget {
 }
 
 class _MyAppState extends State<MyApp> {
-  var _future;
+  late Future<Response> _future;
 
   @override
   void initState() {
     super.initState();
-    _future = get(url);
+    _future = get(Uri.parse(url));
   }
 
   @override
@@ -70,14 +70,14 @@ class _MyAppState extends State<MyApp> {
             ),
             Expanded(
               child: Center(
-                child: FutureBuilder(
+                child: FutureBuilder<Response>(
                   future: _future,
                   builder: (context, snapshot) {
                     if (snapshot.hasData) {
                       return SingleChildScrollView(
                         scrollDirection: Axis.vertical,
                         child: Text(
-                          snapshot.data.body.toString(),
+                          snapshot.data?.body.toString() ?? '',
                         ),
                       );
                     }
diff --git a/example/pubspec.lock b/example/pubspec.lock
index 0bfd337..ad7d819 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -5,51 +5,58 @@ packages:
     dependency: transitive
     description:
       name: async
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.4.1"
+    version: "2.5.0"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.0.0"
+    version: "2.1.0"
+  characters:
+    dependency: transitive
+    description:
+      name: characters
+      url: "https://pub.flutter-io.cn"
+    source: hosted
+    version: "1.1.0"
   charcode:
     dependency: transitive
     description:
       name: charcode
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.3"
+    version: "1.2.0"
   clock:
     dependency: transitive
     description:
       name: clock
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.0.1"
+    version: "1.1.0"
   collection:
     dependency: transitive
     description:
       name: collection
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.14.12"
+    version: "1.15.0"
   cupertino_icons:
     dependency: "direct main"
     description:
       name: cupertino_icons
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.1.3"
+    version: "1.0.2"
   fake_async:
     dependency: transitive
     description:
       name: fake_async
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -64,51 +71,51 @@ packages:
     dependency: transitive
     description:
       name: http
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.12.1"
+    version: "0.13.1"
   http_parser:
     dependency: transitive
     description:
       name: http_parser
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "3.1.4"
+    version: "4.0.0"
   http_proxy:
     dependency: "direct main"
     description:
       path: ".."
       relative: true
     source: path
-    version: "1.0.0"
+    version: "1.1.0"
   matcher:
     dependency: transitive
     description:
       name: matcher
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.12.6"
+    version: "0.12.10"
   meta:
     dependency: transitive
     description:
       name: meta
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.8"
+    version: "1.3.0"
   path:
     dependency: transitive
     description:
       name: path
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.7.0"
+    version: "1.8.0"
   pedantic:
     dependency: transitive
     description:
       name: pedantic
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.9.0"
+    version: "1.11.0"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -118,58 +125,58 @@ packages:
     dependency: transitive
     description:
       name: source_span
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.7.0"
+    version: "1.8.0"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.9.3"
+    version: "1.10.0"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.0.0"
+    version: "2.1.0"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.0.5"
+    version: "1.1.0"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0"
   test_api:
     dependency: transitive
     description:
       name: test_api
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.2.15"
+    version: "0.2.19"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.0.8"
+    version: "2.1.0"
 sdks:
-  dart: ">=2.7.0 <3.0.0"
-  flutter: ">=1.10.0"
+  dart: ">=2.12.0 <3.0.0"
+  flutter: ">=2.0.0"
diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index 2841109..af8c7c8 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -6,7 +6,7 @@ description: Demonstrates how to use the http_proxy plugin.
 publish_to: 'none' # Remove this line if you wish to publish to pub.dev
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   flutter:
@@ -22,7 +22,7 @@ dependencies:
 
   # The following adds the Cupertino Icons font to your application.
   # Use with the CupertinoIcons class for iOS style icons.
-  cupertino_icons: ^0.1.3
+  cupertino_icons: ^1.0.2
 
 dev_dependencies:
   flutter_test:
diff --git a/example/test/widget_test.dart b/example/test/widget_test.dart
index 1e3f1d0..1d7f0b4 100644
--- a/example/test/widget_test.dart
+++ b/example/test/widget_test.dart
@@ -19,7 +19,7 @@ void main() {
     expect(
       find.byWidgetPredicate(
         (Widget widget) => widget is Text &&
-                           widget.data.startsWith('Running on:'),
+            (widget.data?.startsWith('Running on:') ?? false),
       ),
       findsOneWidget,
     );
diff --git a/lib/http_proxy.dart b/lib/http_proxy.dart
index 80fe7c5..45ece77 100644
--- a/lib/http_proxy.dart
+++ b/lib/http_proxy.dart
@@ -3,17 +3,17 @@ import 'package:flutter/services.dart';
 
 MethodChannel _channel = MethodChannel('com.lm.http.proxy');
 
-Future<String> _getProxyHost() async {
+Future<String?> _getProxyHost() async {
   return await _channel.invokeMethod('getProxyHost');
 }
 
-Future<String> _getProxyPort() async {
+Future<String?> _getProxyPort() async {
   return await _channel.invokeMethod('getProxyPort');
 }
 
 class HttpProxy extends HttpOverrides {
-  String host;
-  String port;
+  String? host;
+  String? port;
 
   HttpProxy._(this.host, this.port);
 
@@ -22,7 +22,7 @@ class HttpProxy extends HttpOverrides {
   }
 
   @override
-  HttpClient createHttpClient(SecurityContext context) {
+  HttpClient createHttpClient(SecurityContext? context) {
     var client = super.createHttpClient(context);
     client.badCertificateCallback =
         (X509Certificate cert, String host, int port) {
@@ -32,7 +32,7 @@ class HttpProxy extends HttpOverrides {
   }
 
   @override
-  String findProxyFromEnvironment(Uri url, Map<String, String> environment) {
+  String findProxyFromEnvironment(Uri url, Map<String, String>? environment) {
     if (host == null) {
       return super.findProxyFromEnvironment(url, environment);
     }
diff --git a/pubspec.lock b/pubspec.lock
index 638fdbe..1cf0fbd 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -5,44 +5,51 @@ packages:
     dependency: transitive
     description:
       name: async
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.4.1"
+    version: "2.5.0"
   boolean_selector:
     dependency: transitive
     description:
       name: boolean_selector
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.0.0"
+    version: "2.1.0"
+  characters:
+    dependency: transitive
+    description:
+      name: characters
+      url: "https://pub.flutter-io.cn"
+    source: hosted
+    version: "1.1.0"
   charcode:
     dependency: transitive
     description:
       name: charcode
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.3"
+    version: "1.2.0"
   clock:
     dependency: transitive
     description:
       name: clock
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.0.1"
+    version: "1.1.0"
   collection:
     dependency: transitive
     description:
       name: collection
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.14.12"
+    version: "1.15.0"
   fake_async:
     dependency: transitive
     description:
       name: fake_async
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -57,44 +64,44 @@ packages:
     dependency: "direct main"
     description:
       name: http
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.12.1"
+    version: "0.13.1"
   http_parser:
     dependency: transitive
     description:
       name: http_parser
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "3.1.4"
+    version: "4.0.0"
   matcher:
     dependency: transitive
     description:
       name: matcher
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.12.6"
+    version: "0.12.10"
   meta:
     dependency: transitive
     description:
       name: meta
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.8"
+    version: "1.3.0"
   path:
     dependency: transitive
     description:
       name: path
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.7.0"
+    version: "1.8.0"
   pedantic:
     dependency: transitive
     description:
       name: pedantic
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.9.0"
+    version: "1.11.0"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -104,58 +111,58 @@ packages:
     dependency: transitive
     description:
       name: source_span
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.7.0"
+    version: "1.8.0"
   stack_trace:
     dependency: transitive
     description:
       name: stack_trace
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.9.3"
+    version: "1.10.0"
   stream_channel:
     dependency: transitive
     description:
       name: stream_channel
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.0.0"
+    version: "2.1.0"
   string_scanner:
     dependency: transitive
     description:
       name: string_scanner
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.0.5"
+    version: "1.1.0"
   term_glyph:
     dependency: transitive
     description:
       name: term_glyph
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0"
   test_api:
     dependency: transitive
     description:
       name: test_api
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "0.2.15"
+    version: "0.2.19"
   typed_data:
     dependency: transitive
     description:
       name: typed_data
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "1.1.6"
+    version: "1.3.0"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
-      url: "https://pub.dartlang.org"
+      url: "https://pub.flutter-io.cn"
     source: hosted
-    version: "2.0.8"
+    version: "2.1.0"
 sdks:
-  dart: ">=2.7.0 <3.0.0"
-  flutter: ">=1.10.0"
+  dart: ">=2.12.0 <3.0.0"
+  flutter: ">=2.0.0"
diff --git a/pubspec.yaml b/pubspec.yaml
index 5f25653..8a67e8a 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -5,13 +5,13 @@ homepage: https://github.com/wslaimin
 repository: https://github.com/wslaimin/http_proxy
 
 environment:
-  sdk: ">=2.7.0 <3.0.0"
-  flutter: ">=1.10.0"
+  sdk: ">=2.12.0 <3.0.0"
+  flutter: ">=2.0.0"
 
 dependencies:
   flutter:
     sdk: flutter
-  http: ^0.12.1
+  http: ^0.13.1
 
 dev_dependencies:
   flutter_test: