Forever "Waiting for application to start debug server" when debugging a WatchFace

Question

I'm learning to develop watch faces under WearOS, with Android Studio 3.1.4. I have issues with the debugger.

It seems I can't run the application directly in debug mode (Shift-F9). If I do so, I systematically get the following message, despite having authorized debugging on the watch (emulator or real watch (Huawai Watch 2)):

08/24 09:03:00: Launching wearmodule
$ adb push     /path/wearmodule/build/outputs/apk/debug/wearmodule-debug.apk /data/local/tmp/com.example.wearmodule
$ adb shell pm install -t -r "/data/local/tmp/com.example.wearmodule"
Success


Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Waiting for application to come online: com.example.wearmodule.test | com.example.wearmodule
Connecting to com.example.wearmodule
Waiting for application to start debug server
Could not connect to remote process. Aborting debug session.

If I understand correctly, a debug server has to start on the watch itself. How can I achieve that?

The only option if I want to debug my watch is to run the app in normal mode (Shift-F10) and then attach a debugger to the process.

This is not ideal because it does not allow me to troubleshoot the initialization process of my code. In particular, methods like initializeWatchFace(), onCreate() or onSurfaceChanged() can't be debugged, which is really annoying.

Is there anything special to be done on the watch itself, in the manifest, somewhere, to fix this? Can it be linked to the fact that my app has no activity (as taught in the Google CodeLab). I've seem messages linking these issues to activities managment.

Answer 1

Another option is to override the onCreate method on your watch face service and call Debug.waitForDebugger()

override fun onCreate() {
    Debug.waitForDebugger()
    super.onCreate()
}

Use Run in Android Studio so your watch face service is installed in your watch. Then in Android Studio go to the Run top menu and there select Attach to Process....

waitForDebugger basically puts the main thread on pause until a debugger has been attached. You can place Debug.waitForDebugger wherever it makes more sense in your code.