Add splash screen to avoid white screen while opening (#112)

app/src/main/AndroidManifest.xml

@@ -25,7 +25,7 @@
         </activity>
         <activity
             android:name=".MainActivity"
-            android:theme="@style/AppTheme.NoActionBar">
+            android:theme="@style/AppTheme.Launcher">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 

app/src/main/java/com/h/pixeldroid/MainActivity.kt

@@ -29,6 +29,7 @@ class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelecte
     private lateinit var preferences: SharedPreferences
 
     override fun onCreate(savedInstanceState: Bundle?) {
+        setTheme(R.style.AppTheme_NoActionBar)
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
 

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

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android" android:opacity="opaque">
+    <!-- The background color, preferably the same as your normal theme -->
+    <item android:drawable="@android:color/white"/>
+    <!-- Your product logo - 144dp color version of your app icon -->
+    <item>
+        <bitmap
+            android:src="@drawable/index"
+            android:gravity="center"/>
+    </item>
+</layer-list>

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

@@ -7,7 +7,9 @@
         <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
         <item name="colorAccent">@color/colorAccent</item>
     </style>
-
+    <style name="AppTheme.Launcher">
+        <item name="android:windowBackground">@drawable/theme</item>
+    </style>
     <style name="AppTheme.NoActionBar">
         <item name="windowActionBar">false</item>
         <item name="windowNoTitle">true</item>