<?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.wenchen.myfirebase">

   <application
       android:allowBackup = "true"
       android:icon        = "@mipmap/ic_launcher"
       android:label       = "@string/app_name"
       android:roundIcon   = "@mipmap/ic_launcher_round"
       android:supportsRtl = "true"
       android:theme       = "@style/Theme.MyFirebase">

     <activity android:name=".MainActivity">
       <intent-filter>
         <action android:name   = "android.intent.action.MAIN" />
         <category android:name = "android.intent.category.LAUNCHER" />
       </intent-filter>
     </activity>

   </application>
 </manifest>