Supporting the new Android plugins APIs & compatibility with flutter 3

android/src/main/kotlin/com/drenther/upi_pay/UpiPayPlugin.kt

@@ -1,5 +1,6 @@
 package com.drenther.upi_pay
 
+import android.app.Activity
 import android.content.Intent
 import android.content.pm.PackageManager
 import android.graphics.Bitmap
@@ -8,21 +9,29 @@ import android.graphics.drawable.Drawable
 import android.net.Uri
 import android.util.Base64
 import android.util.Log
+import androidx.annotation.NonNull
+import io.flutter.embedding.engine.plugins.FlutterPlugin
+import io.flutter.embedding.engine.plugins.activity.ActivityAware
+import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding
 import io.flutter.plugin.common.MethodCall
 import io.flutter.plugin.common.MethodChannel
-import io.flutter.plugin.common.MethodChannel.MethodCallHandler
 import io.flutter.plugin.common.MethodChannel.Result
-import io.flutter.plugin.common.PluginRegistry.ActivityResultListener
-import io.flutter.plugin.common.PluginRegistry.Registrar
+import io.flutter.plugin.common.MethodChannel.MethodCallHandler
+import io.flutter.plugin.common.PluginRegistry
 import java.io.ByteArrayOutputStream
 
-class UpiPayPlugin internal constructor(registrar: Registrar, channel: MethodChannel) : MethodCallHandler, ActivityResultListener {
-  private val activity = registrar.activity()
+class UpiPayPlugin: FlutterPlugin, MethodCallHandler, ActivityAware, PluginRegistry.ActivityResultListener {
+  /// The MethodChannel that will the communication between Flutter and native Android
+  ///
+  /// This local reference serves to register the plugin with the Flutter Engine and unregister it
+  /// when the Flutter Engine is detached from the Activity
+  private lateinit var channel : MethodChannel
+  private var activity: Activity? = null
 
   private var result: Result? = null
   private var requestCodeNumber = 201119
 
-  var hasResponded = false
+  private var hasResponded = false
 
   override fun onMethodCall(call: MethodCall, result: Result) {
     hasResponded = false
@@ -75,12 +84,13 @@ class UpiPayPlugin internal constructor(registrar: Registrar, channel: MethodCha
       val intent = Intent(Intent.ACTION_VIEW, uri)
       intent.setPackage(app)
 
-      if (intent.resolveActivity(activity.packageManager) == null) {
+      if (activity?.let { intent.resolveActivity(it.packageManager) } == null) {
         this.success("activity_unavailable")
         return
       }
 
-      activity.startActivityForResult(intent, requestCodeNumber)
+      activity?.startActivityForResult(intent, requestCodeNumber)
+
     } catch (ex: Exception) {
       Log.e("upi_pay", ex.toString())
       this.success("failed_to_open_app")
@@ -94,29 +104,25 @@ class UpiPayPlugin internal constructor(registrar: Registrar, channel: MethodCha
     val uri = uriBuilder.build()
     val intent = Intent(Intent.ACTION_VIEW, uri)
 
-    val packageManager = activity.packageManager
+    val packageManager = activity?.packageManager
 
     try {
-      val activities = packageManager.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY)
+      val activities = packageManager?.queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY)
 
       // Convert the activities into a response that can be transferred over the channel.
-      val activityResponse = activities.map {
-        val packageName = it.activityInfo.packageName
-        val drawable = packageManager.getApplicationIcon(packageName)
-
-        val bitmap = getBitmapFromDrawable(drawable)
-        val icon = if (bitmap != null) {
-          encodeToBase64(bitmap)
-        } else {
-          null
-        }
-
-        mapOf(
-                "packageName" to packageName,
-                "icon" to icon,
-                "priority" to it.priority,
-                "preferredOrder" to it.preferredOrder
-        )
+      val activityResponse = activities?.map {
+          val packageName = it.activityInfo.packageName
+          val drawable = packageManager.getApplicationIcon(packageName)
+
+          val bitmap = getBitmapFromDrawable(drawable)
+          val icon = encodeToBase64(bitmap)
+
+          mapOf(
+            "packageName" to packageName,
+            "icon" to icon,
+            "priority" to it.priority,
+            "preferredOrder" to it.preferredOrder
+          )
       }
 
       result?.success(activityResponse)
@@ -132,10 +138,10 @@ class UpiPayPlugin internal constructor(registrar: Registrar, channel: MethodCha
     return Base64.encodeToString(byteArrayOS.toByteArray(), Base64.NO_WRAP)
   }
 
-  private fun getBitmapFromDrawable(drawable: Drawable): Bitmap? {
+  private fun getBitmapFromDrawable(drawable: Drawable): Bitmap {
     val bmp: Bitmap = Bitmap.createBitmap(drawable.intrinsicWidth, drawable.intrinsicHeight, Bitmap.Config.ARGB_8888)
     val canvas = Canvas(bmp)
-    drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight())
+    drawable.setBounds(0, 0, canvas.width, canvas.height)
     drawable.draw(canvas)
     return bmp
   }
@@ -147,6 +153,7 @@ class UpiPayPlugin internal constructor(registrar: Registrar, channel: MethodCha
     }
   }
 
+
   override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?): Boolean {
     if (requestCodeNumber == requestCode && result != null) {
       if (data != null) {
@@ -163,13 +170,31 @@ class UpiPayPlugin internal constructor(registrar: Registrar, channel: MethodCha
     return true
   }
 
-  companion object {
-    @JvmStatic
-    fun registerWith(registrar: Registrar) {
-      val channel = MethodChannel(registrar.messenger(), "upi_pay")
-      val plugin = UpiPayPlugin(registrar, channel)
-      registrar.addActivityResultListener(plugin)
-      channel.setMethodCallHandler(plugin)
-    }
+
+  override fun onAttachedToEngine(@NonNull flutterPluginBinding: FlutterPlugin.FlutterPluginBinding) {
+    channel = MethodChannel(flutterPluginBinding.binaryMessenger, "upi_pay")
+    channel.setMethodCallHandler(this)
+  }
+
+  override fun onDetachedFromEngine(@NonNull binding: FlutterPlugin.FlutterPluginBinding) {
+    channel.setMethodCallHandler(null)
   }
+
+  override fun onAttachedToActivity(binding: ActivityPluginBinding) {
+    activity = binding.activity
+    binding.addActivityResultListener(this)
+  }
+
+  override fun onDetachedFromActivityForConfigChanges() {
+    onDetachedFromActivity()
+  }
+
+  override fun onReattachedToActivityForConfigChanges(binding: ActivityPluginBinding) {
+    activity = binding.activity
+  }
+
+  override fun onDetachedFromActivity() {
+    activity = null
+  }
+
 }

example/android/app/build.gradle

@@ -26,7 +26,17 @@ apply plugin: 'kotlin-android'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
 android {
-    compileSdkVersion 30
+    compileSdkVersion flutter.compileSdkVersion
+    ndkVersion flutter.ndkVersion
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
 
     sourceSets {
         main.java.srcDirs += 'src/main/kotlin'
@@ -35,8 +45,10 @@ android {
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId "com.drenther.upi_pay_example"
-        minSdkVersion 16
-        targetSdkVersion 30
+        // You can update the following values to match your application needs.
+        // For more information, see: https://docs.flutter.dev/deployment/android#reviewing-the-build-configuration.
+        minSdkVersion flutter.minSdkVersion
+        targetSdkVersion flutter.targetSdkVersion
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName
     }

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

@@ -9,6 +9,7 @@
             android:theme="@style/LaunchTheme"
             android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
             android:hardwareAccelerated="true"
+            android:exported="true"
             android:windowSoftInputMode="adjustResize">
             <!-- Specifies an Android theme to apply to this Activity as soon as
                  the Android process has started. This theme is visible to the user

example/android/build.gradle

@@ -1,5 +1,5 @@
 buildscript {
-    ext.kotlin_version = '1.3.50'
+    ext.kotlin_version = '1.6.10'
     repositories {
         google()
         jcenter()

example/pubspec.lock

@@ -14,7 +14,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.6.1"
+    version: "2.8.2"
   boolean_selector:
     dependency: transitive
     description:
@@ -28,14 +28,14 @@ packages:
       name: characters
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.1.0"
+    version: "1.2.0"
   charcode:
     dependency: transitive
     description:
       name: charcode
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0"
+    version: "1.3.1"
   clock:
     dependency: transitive
     description:
@@ -49,7 +49,7 @@ packages:
       name: collection
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.15.0"
+    version: "1.16.0"
   crypto:
     dependency: transitive
     description:
@@ -77,7 +77,7 @@ packages:
       name: fake_async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.2.0"
+    version: "1.3.0"
   flutter:
     dependency: "direct main"
     description: flutter
@@ -94,21 +94,28 @@ packages:
       name: matcher
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.12.10"
+    version: "0.12.11"
+  material_color_utilities:
+    dependency: transitive
+    description:
+      name: material_color_utilities
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.1.4"
   meta:
     dependency: transitive
     description:
       name: meta
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.3.0"
+    version: "1.7.0"
   path:
     dependency: transitive
     description:
       name: path
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.0"
+    version: "1.8.1"
   platform:
     dependency: transitive
     description:
@@ -134,7 +141,7 @@ packages:
       name: source_span
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "1.8.1"
+    version: "1.8.2"
   stack_trace:
     dependency: transitive
     description:
@@ -169,7 +176,7 @@ packages:
       name: test_api
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.0"
+    version: "0.4.9"
   typed_data:
     dependency: transitive
     description:
@@ -190,14 +197,14 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "1.0.0"
+    version: "2.0.0"
   vector_math:
     dependency: transitive
     description:
       name: vector_math
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.1.0"
+    version: "2.1.2"
 sdks:
-  dart: ">=2.12.0 <3.0.0"
+  dart: ">=2.17.0-0 <3.0.0"
   flutter: ">2.0.0"