Flutter Android ERROR: ensureInitializationComplete must be called after startInitialization

Question

Currently I'm trying to add a flutter app to my android app but when I try to do an Intent the app crashes and prints the following issue:

I followed this guide here

I get this error:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.testappandroid/io.flutter.embedding.android.FlutterActivity}: java.lang.IllegalStateException: ensureInitializationComplete must be called after startInitialization
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2913)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3048)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1808)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6669)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
     Caused by: java.lang.IllegalStateException: ensureInitializationComplete must be called after startInitialization
        at io.flutter.view.FlutterMain.ensureInitializationComplete(FlutterMain.java:168)
        at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.initializeFlutter(FlutterActivityAndFragmentDelegate.java:177)
        at io.flutter.embedding.android.FlutterActivityAndFragmentDelegate.onAttach(FlutterActivityAndFragmentDelegate.java:140)
        at io.flutter.embedding.android.FlutterActivity.onCreate(FlutterActivity.java:399)
        at android.app.Activity.performCreate(Activity.java:7136)
        at android.app.Activity.performCreate(Activity.java:7127)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2893)

So it says: ensureInitializationComplete must be called after startInitialization. One solution is to call FlutterMain.startInitialization(this) in the Flutter Activity. But this isn't working for me:

My Flutter Activity:

public class MainActivity extends FlutterActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
FlutterMain.startInitialization(this);
    super.onCreate(savedInstanceState);
    GeneratedPluginRegistrant.registerWith(this);
  }
}

My android app AndroidManifest:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="com.example.testappandroid">
    <uses-permission android:name="android.permission.INTERNET" />
    <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/AppTheme"
        tools:ignore="GoogleAppIndexingWarning">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="io.flutter.embedding.android.FlutterActivity"
            android:theme="@style/AppTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize"
            android:exported="true">
            <meta-data
                android:name="io.flutter.Entrypoint"
                android:value="main"
                />
        </activity>

    </application>

</manifest>

My flutter module AndroidManifest:

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

    <!-- The INTERNET permission is required for development. Specifically,
         flutter needs it to communicate with the running application
         to allow setting breakpoints, to provide hot reload, etc.
    -->
    <uses-permission android:name="android.permission.INTERNET"/>

    <!-- io.flutter.app.FlutterApplication is an android.app.Application that
         calls FlutterMain.startInitialization(this); in its onCreate method.
         In most cases you can leave this as-is, but you if you want to provide
         additional functionality it is fine to subclass or reimplement
         FlutterApplication and put your custom class here. -->
    <application
        android:name="io.flutter.app.FlutterApplication"
        android:label="testappflutter"
        android:icon="@mipmap/ic_launcher">
        <activity
            android:name=".MainActivity"
            android:launchMode="singleTop"
            android:theme="@style/LaunchTheme"
            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
            android:hardwareAccelerated="true"
            android:windowSoftInputMode="adjustResize">
            <!-- This keeps the window background of the activity showing
                 until Flutter renders its first frame. It can be removed if
                 there is no splash screen (such as the default splash screen
                 defined in @style/LaunchTheme). -->
            <meta-data
                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
                android:value="true" />
            <intent-filter>
                <action android:name="android.intent.action.MAIN"/>
                <category android:name="android.intent.category.LAUNCHER"/>
            </intent-filter>
        </activity>
    </application>
</manifest>

With this line of code I try to open the FlutterActivtiy. This is calling the main() function in my dart code:

Intent defaultFlutter = createDefaultIntent(activity);
activity.startActivity(defaultFlutter);

The code above should start this:

void main() => runApp(MaterialApp(
  routes: {
    "/": (context) => TestWidget()
  }
));

So I followed step by step the guide for adding Flutter to an existing android app. Do I forget something? In my mind maybe the AndroidManifest of the flutter app needs some changes? Any ideas what I'm doing wrong?

Answer 1

insure that you import the right packages:

import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.engine.FlutterEngine;

instead of

import io.flutter.app.FlutterActivity

in your MainActivity so your Main activity should look like this:

package com.example.example
import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.engine.FlutterEngine;
class MainActivity: FlutterActivity() {

}

Answer 2

FlutterMain.startInitialization(this);

Add This Line Before Super.Create like

FlutterMain.startInitialization(this) //Added line
super.onCreate(savedInstanceState)
GeneratedPluginRegistrant.registerWith(this)