add gradient

example/android/.gitignore

@@ -0,0 +1,11 @@
+gradle-wrapper.jar
+/.gradle
+/captures/
+/gradlew
+/gradlew.bat
+/local.properties
+GeneratedPluginRegistrant.java
+
+# Remember to never publicly share your keystore.
+# See https://flutter.dev/docs/deployment/android#reference-the-keystore-from-the-app
+key.properties

example/android/app/build.gradle

@@ -25,20 +25,19 @@ apply plugin: 'com.android.application'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 27
+    compileSdkVersion 29
 
     lintOptions {
         disable 'InvalidPackage'
     }
 
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
-        applicationId "com.example.sample"
+        applicationId "com.example.example"
         minSdkVersion 16
-        targetSdkVersion 27
+        targetSdkVersion 29
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
     }
 
     buildTypes {
@@ -53,9 +52,3 @@ android {
 flutter {
     source '../..'
 }
-
-dependencies {
-    testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'com.android.support.test:runner:1.0.2'
-    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
-}

example/android/app/src/debug/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.example">
+    <!-- Flutter needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

example/android/app/src/main/AndroidManifest.xml

@@ -1,39 +1,47 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="com.example.sample">
-
-    <!-- The INTERNET permission is required for development. Specifically,
-         flutter needs it to communicate with the running application
-         to allow setting breakpoints, to provide hot reload, etc.
-    -->
-    <uses-permission android:name="android.permission.INTERNET"/>
-
+    package="com.example.example">
     <!-- io.flutter.app.FlutterApplication is an android.app.Application that
          calls FlutterMain.startInitialization(this); in its onCreate method.
          In most cases you can leave this as-is, but you if you want to provide
          additional functionality it is fine to subclass or reimplement
          FlutterApplication and put your custom class here. -->
     <application
         android:name="io.flutter.app.FlutterApplication"
-        android:label="sample"
+        android:label="example"
         android:icon="@mipmap/ic_launcher">
         <activity
             android:name=".MainActivity"
             android:launchMode="singleTop"
             android:theme="@style/LaunchTheme"
-            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density"
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
             android:hardwareAccelerated="true"
             android:windowSoftInputMode="adjustResize">
-            <!-- This keeps the window background of the activity showing
-                 until Flutter renders its first frame. It can be removed if
-                 there is no splash screen (such as the default splash screen
-                 defined in @style/LaunchTheme). -->
+            <!-- Specifies an Android theme to apply to this Activity as soon as
+                 the Android process has started. This theme is visible to the user
+                 while the Flutter UI initializes. After that, this theme continues
+                 to determine the Window background behind the Flutter UI. -->
             <meta-data
-                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
-                android:value="true" />
+              android:name="io.flutter.embedding.android.NormalTheme"
+              android:resource="@style/NormalTheme"
+              />
+            <!-- Displays an Android View that continues showing the launch screen
+                 Drawable until Flutter paints its first frame, then this splash
+                 screen fades out. A splash screen is useful to avoid any visual
+                 gap between the end of Android's launch screen and the painting of
+                 Flutter's first frame. -->
+            <meta-data
+              android:name="io.flutter.embedding.android.SplashScreenDrawable"
+              android:resource="@drawable/launch_background"
+              />
             <intent-filter>
                 <action android:name="android.intent.action.MAIN"/>
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
+        <!-- Don't delete the meta-data below.
+             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
+        <meta-data
+            android:name="flutterEmbedding"
+            android:value="2" />
     </application>
 </manifest>

example/android/app/src/main/java/com/example/example/MainActivity.java

@@ -0,0 +1,6 @@
+package com.example.example;
+
+import io.flutter.embedding.android.FlutterActivity;
+
+public class MainActivity extends FlutterActivity {
+}

example/android/app/src/main/res/values/styles.xml

@@ -1,8 +1,18 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
+    <!-- Theme applied to the Android Window while the process is starting -->
     <style name="LaunchTheme" parent="@android:style/Theme.Black.NoTitleBar">
         <!-- Show a splash screen on the activity. Automatically removed when
              Flutter draws its first frame -->
         <item name="android:windowBackground">@drawable/launch_background</item>
     </style>
+    <!-- Theme applied to the Android Window as soon as the process has started.
+         This theme determines the color of the Android Window while your
+         Flutter UI initializes, as well as behind your Flutter UI while its
+         running.
+
+         This Theme is only used starting with V2 of Flutter's Android embedding. -->
+    <style name="NormalTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <item name="android:windowBackground">@android:color/white</item>
+    </style>
 </resources>

example/android/app/src/profile/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.example.example">
+    <!-- Flutter needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

example/android/build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.1'
+        classpath 'com.android.tools.build:gradle:3.5.0'
     }
 }
 

example/android/gradle.properties

@@ -1 +1,4 @@
 org.gradle.jvmargs=-Xmx1536M
+android.useAndroidX=true
+android.enableJetifier=true
+android.enableR8=true

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-4.10.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip

example/android/settings.gradle

@@ -1,15 +1,11 @@
 include ':app'
 
-def flutterProjectRoot = rootProject.projectDir.parentFile.toPath()
+def localPropertiesFile = new File(rootProject.projectDir, "local.properties")
+def properties = new Properties()
 
-def plugins = new Properties()
-def pluginsFile = new File(flutterProjectRoot.toFile(), '.flutter-plugins')
-if (pluginsFile.exists()) {
-    pluginsFile.withReader('UTF-8') { reader -> plugins.load(reader) }
-}
+assert localPropertiesFile.exists()
+localPropertiesFile.withReader("UTF-8") { reader -> properties.load(reader) }
 
-plugins.each { name, path ->
-    def pluginDirectory = flutterProjectRoot.resolve(path).resolve('android').toFile()
-    include ":$name"
-    project(":$name").projectDir = pluginDirectory
-}
+def flutterSdkPath = properties.getProperty("flutter.sdk")
+assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
+apply from: "$flutterSdkPath/packages/flutter_tools/gradle/app_plugin_loader.gradle"

example/lib/src/app.dart

@@ -1,3 +1,5 @@
+import 'dart:math';
+
 import 'package:flutter/material.dart';
 import 'package:progress_indicator_button/progress_button.dart';
 
@@ -16,6 +18,12 @@ class App extends StatelessWidget {
             height: 60,
             child: ProgressButton(
               borderRadius: BorderRadius.all(Radius.circular(8)),
+              gradient: new LinearGradient(
+                colors: <Color>[
+                  Colors.red,
+                  Colors.blue,
+                ]
+              ),
               strokeWidth: 2,
               child: Text(
                 "Sample",
@@ -24,12 +32,20 @@ class App extends StatelessWidget {
                   fontSize: 24,
                 ),
               ),
-              onPressed: (AnimationController controller) {
-                if (controller.isCompleted) {
-                  controller.reverse();
-                } else {
-                  controller.forward();
-                }
+              errorChild: const Icon(
+                Icons.close_sharp,
+                color: Colors.white,
+              ),
+              successChild: const Icon(
+                Icons.check_sharp,
+                color: Colors.white,
+              ),
+              onPressed: ( controller ) async {
+                await controller.loading();
+                await new Future.delayed( const Duration( seconds: 3 ) );
+                if ( Random.secure().nextBool() )
+                  await controller.success();
+                else await controller.error();
               },
             ),
           ),

example/pubspec.yaml

@@ -10,7 +10,7 @@ description: An example for the progress button implementation.
 version: 1.0.0+1
 
 environment:
-  sdk: ">=2.0.0-dev.68.0 <3.0.0"
+  sdk: ">=2.7.0 <3.0.0"
 
 dependencies:
   flutter: