Added push notifications, FCM.

android/app/build.gradle

@@ -24,6 +24,10 @@ if (flutterVersionName == null) {
 apply plugin: 'com.android.application'
 apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
 
+if (file("./google-services.json").exists()) {
+    apply plugin: 'com.google.gms.google-services'
+}
+
 def keystoreProperties = new Properties()
 def keystorePropertiesFile = rootProject.file('key.properties')
 if (keystorePropertiesFile.exists()) {
@@ -83,4 +87,6 @@ dependencies {
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test:runner:1.1.1'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
+    implementation 'com.google.firebase:firebase-core:19.0.0'
+    implementation 'com.google.firebase:firebase-messaging:19.0.0'
 }

android/app/src/main/AndroidManifest.xml

@@ -7,6 +7,7 @@
     <uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE" />
 
     <application
+        android:name=".Application"
         android:label="Cake Wallet"
         android:allowBackup="false"
         android:fullBackupContent="false"
@@ -29,7 +30,6 @@
                 <category android:name="android.intent.category.LAUNCHER"/>
             </intent-filter>
         </activity>
-
         <meta-data
                 android:name="flutterEmbedding"
                 android:value="2" />

android/app/src/main/java/com/cakewallet/cake_wallet/Application.java

@@ -0,0 +1,21 @@
+package com.cakewallet.cake_wallet;
+
+import io.flutter.app.FlutterApplication;
+import io.flutter.plugin.common.PluginRegistry;
+import io.flutter.plugin.common.PluginRegistry.PluginRegistrantCallback;
+import io.flutter.plugins.GeneratedPluginRegistrant;
+import io.flutter.plugins.firebasemessaging.FlutterFirebaseMessagingService;
+import io.flutter.plugins.firebasemessaging.FirebaseMessagingPlugin;
+
+public class Application extends FlutterApplication implements PluginRegistrantCallback {
+  @Override
+  public void onCreate() {
+    super.onCreate();
+    FlutterFirebaseMessagingService.setPluginRegistrant(this);
+  }
+
+  @Override
+  public void registerWith(PluginRegistry registry) {
+    FirebaseMessagingPlugin.registerWith(registry.registrarFor("io.flutter.plugins.firebasemessaging.FirebaseMessagingPlugin"));
+  }
+}

android/build.gradle

@@ -6,6 +6,7 @@ buildscript {
 
     dependencies {
         classpath 'com.android.tools.build:gradle:3.5.4'
+        classpath 'com.google.gms:google-services:4.3.8'
     }
 }