added androidX support

android/build.gradle

@@ -1,6 +1,18 @@
 group 'com.flutter_webview_plugin'
 version '1.0-SNAPSHOT'
 
+def ANDROIDX_WARNING = "flutterPluginsAndroidXWarning";
+gradle.buildFinished { buildResult ->
+    if (buildResult.failure && !rootProject.ext.has(ANDROIDX_WARNING)) {
+        println '         *********************************************************'
+        println 'WARNING: This version of flutter_webview_plugin will break your Android build if it or its dependencies aren\'t compatible with AndroidX.'
+        println '         See https://goo.gl/CP92wY for more information on the problem and how to fix it.'
+        println '         This warning prints for all Android build failures. The real root cause of the error may be unrelated.'
+        println '         *********************************************************'
+        rootProject.ext.set(ANDROIDX_WARNING, true);
+    }
+}
+
 buildscript {
     repositories {
         google()
@@ -8,7 +20,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.1'
+        classpath 'com.android.tools.build:gradle:3.3.2'
     }
 }
 
@@ -21,10 +33,10 @@ allprojects {
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion 28
 
     defaultConfig {
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         // NOTE(jeffmikels): When targetSdkVersion or minSdkVersion is not set or < 4, gradle adds 
         // additional scary permissions such as WRITE_EXTERNAL_STORAGE and READ_PHONE_STATE.
         minSdkVersion 16

example/android/app/build.gradle

@@ -15,7 +15,7 @@ apply plugin: 'com.android.application'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion 28
 
     lintOptions {
         disable 'InvalidPackage'
@@ -42,7 +42,7 @@ flutter {
 }
 
 dependencies {
-    androidTestImplementation 'com.android.support:support-annotations:27.0.0'
-    androidTestImplementation 'com.android.support.test:runner:1.0.2'
-    androidTestImplementation 'com.android.support.test:rules:1.0.2'
+    androidTestImplementation 'androidx.annotation:annotation:1.0.2'
+    androidTestImplementation 'androidx.test:runner:1.1.1'
+    androidTestImplementation 'androidx.test:rules:1.1.1'
 }

example/android/build.gradle

@@ -8,7 +8,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.1'
+        classpath 'com.android.tools.build:gradle:3.3.2'
     }
 }
 
@@ -33,5 +33,5 @@ task clean(type: Delete) {
 }
 
 task wrapper(type: Wrapper) {
-    gradleVersion = '2.14.1'
+    gradleVersion = '4.10.2'
 }

example/android/gradle.properties

@@ -1 +1,3 @@
 org.gradle.jvmargs=-Xmx1536M
+android.useAndroidX=true
+android.enableJetifier=false