No implementation found for long io.flutter.embedding.engine.FlutterJNI.nativeAttach

[luoyushouchai]

I add flutter project to my existed app!
https://github.com/flutter/flutter/wiki/Add-Flutter-to-existing-apps

  @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        FlutterEngine flutterEngine = new FlutterEngine(this);
        MethodChannel channel = new MethodChannel(flutterEngine.getDartExecutor(), "TestChannel");

    }

Using FlutterEngine getDartExecutor() to create a MethodChannel!

The error comes:

java.lang.UnsatisfiedLinkError: No implementation found for long io.flutter.embedding.engine.FlutterJNI.nativeAttach(io.flutter.embedding.engine.FlutterJNI, boolean) (tried Java_io_flutter_embedding_engine_FlutterJNI_nativeAttach and Java_io_flutter_embedding_engine_FlutterJNI_nativeAttach__Lio_flutter_embedding_engine_FlutterJNI_2Z)
        at io.flutter.embedding.engine.FlutterJNI.nativeAttach(Native Method)
        at io.flutter.embedding.engine.FlutterJNI.attachToNative(FlutterJNI.java:408)
        at io.flutter.embedding.engine.FlutterEngine.attachToJni(FlutterEngine.java:128)
        at io.flutter.embedding.engine.FlutterEngine.<init>(FlutterEngine.java:105)
        at com.example.myapplication.MainActivity.onCreate(MainActivity.java:16)
        at android.app.Activity.performCreate(Activity.java:7149)
        at android.app.Activity.performCreate(Activity.java:7140)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1288)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3017)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3172)
        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$H.handleMessage(ActivityThread.java:1906)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6863)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:537)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

The java file: FlutterJnt

 private native long nativeAttach(FlutterJNI var1, boolean var2);

Can not found implementation!
Some Help?

[luoyushouchai]

Result of flutter doctor:

Doctor summary (to see all details, run flutter doctor -v):
[✓] Flutter (Channel master, v1.3.9-pre.41, on Linux, locale en_US.UTF-8)
[✓] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
[✓] Android Studio (version 3.1)
[!] IntelliJ IDEA Ultimate Edition (version 2018.1)
✗ Flutter plugin not installed; this adds Flutter specific functionality.
✗ Dart plugin not installed; this adds Dart specific functionality.
[✓] Connected device (1 available)

! Doctor found issues in 1 category.

[dnfield]

/cc @matthew-carroll

[matthew-carroll]

@luoyushouchai The FlutterEngine class on Android is experimental and should not be used at this time. Can you point me to the part of the doc that instructs you to use that? I didn't see it.

[luoyushouchai]

@matthew-carroll For ios, Flutter engine can run without view attached to native view. I execute flutter upgrade, seeing flutter.jar for android has FlutterEngine.class. I just test it. Thanks!

[matthew-carroll]

Ok, so it sounds like this issue was just a misunderstanding about FlutterEngine on Android. I'm going to close it. Once FlutterEngine is stable, issues like this should be gone.

[luoyushouchai]

@matthew-carroll
How can i create MethodChannel without FlutterView for now for android platform?

[matthew-carroll]

@luoyushouchai it depends a bit on what you are specifically trying to do. FlutterView, itself, is a BinaryMessenger so you should be able to send messages through FlutterView and register a channel handles with FlutterView.

https://docs.flutter.io/javadoc/io/flutter/view/FlutterView.html

Another option is that you could define your method channels within your own Flutter plugin and then add that plugin to your pubspec file like any other.

[luoyushouchai]

@matthew-carroll Thanks!

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.