Display a splash screen when the app starts.

app/src/main/res/drawable/splash_screen.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android" android:opacity="opaque">
+
+    <item android:drawable="@color/backgroundColor" />
+
+    <item>
+        <bitmap
+            android:src="@drawable/splash_icon"
+            android:gravity="center" />
+    </item>
+
+</layer-list>

app/src/main/res/values-night-v27/styles.xml

@@ -0,0 +1,8 @@
+<resources>
+
+    <style name="AppTheme.Launcher" parent="@style/AppTheme.NoActionBarWithTransparentStatusBar">
+        <item name="android:windowBackground">@drawable/splash_screen</item>
+        <item name="android:navigationBarColor">@color/navBarColor</item>
+    </style>
+
+</resources>

app/src/main/res/values-v27/styles.xml

@@ -0,0 +1,10 @@
+<resources>
+
+    <style name="AppTheme.Launcher" parent="@style/AppTheme.NoActionBarWithTransparentStatusBar">
+        <item name="android:windowBackground">@drawable/splash_screen</item>
+        <item name="android:navigationBarColor">@color/navBarColor</item>
+        <item name="android:windowLightStatusBar">true</item>
+        <item name="android:windowLightNavigationBar">true</item>
+    </style>
+
+</resources>

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

@@ -10,6 +10,10 @@
         <item name="android:textColorPrimary">@android:color/white</item>
     </style>
 
+    <style name="AppTheme.Launcher" parent="@style/AppTheme.NoActionBarWithTransparentStatusBar">
+        <item name="android:windowBackground">@drawable/splash_screen</item>
+    </style>
+
     <style name="AppTheme.NoActionBar">
         <item name="windowActionBar">false</item>
         <item name="windowNoTitle">true</item>