Add Android icon

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

@@ -58,6 +58,7 @@
          An example Java class can be found in README-android.md
     -->
     <application android:label="@string/app_name"
+        android:icon="@mipmap/ic_launcher"
         android:allowBackup="true"
         android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
         android:hardwareAccelerated="true" >

os/android/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@color/ic_launcher_background"/>
+    <foreground android:drawable="@mipmap/ic_launcher_foreground"/>
+</adaptive-icon>

os/android/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@color/ic_launcher_background"/>
+    <foreground android:drawable="@mipmap/ic_launcher_foreground"/>
+</adaptive-icon>

os/android/app/src/main/res/values/ic_launcher_background.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="ic_launcher_background">#000000</color>
+</resources>