NPE when running in a background service

[ened]

🔙 Regression

The plugin shows a error when being started in a background service.
This seems to be related to the V2 embedding.

Old (and correct) behavior

No crash on V1 embedding.

Current behavior

2020-03-31 22:30:26.265 15821-15821/com.mynextbase.connect E/MethodChannel#flutter.baseflow.com/google_api_availability/methods: Failed to handle method call
    java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Context.getPackageName()' on a null object reference
        at com.google.android.gms.common.GooglePlayServicesUtilLight.isGooglePlayServicesAvailable(Unknown Source:12)
        at com.google.android.gms.common.GoogleApiAvailabilityLight.isGooglePlayServicesAvailable(Unknown Source:5)
        at com.google.android.gms.common.GoogleApiAvailability.isGooglePlayServicesAvailable(com.google.android.gms:play-services-base@@17.1.0:96)
        at com.google.android.gms.common.GoogleApiAvailabilityLight.isGooglePlayServicesAvailable(Unknown Source:3)
        at com.google.android.gms.common.GoogleApiAvailability.isGooglePlayServicesAvailable(com.google.android.gms:play-services-base@@17.1.0:95)
        at com.baseflow.googleapiavailability.GoogleApiAvailabilityPlugin.onMethodCall(GoogleApiAvailabilityPlugin.java:105)
        at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:226)
        at io.flutter.embedding.engine.dart.DartMessenger.handleMessageFromDart(DartMessenger.java:85)
        at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessage(FlutterJNI.java:631)
        at android.os.MessageQueue.nativePollOnce(Native Method)
        at android.os.MessageQueue.next(MessageQueue.java:336)
        at android.os.Looper.loop(Looper.java:174)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

Reproduction steps

Run the plugin in a background service.

Configuration

Version: 2.0.3

Platform:

• 📱 iOS
• 🤖 Android

The implementation of the V2 embedding seems a little complicated.
The applicationContext should always be available to the GoogleApiAvailabilityPlugin class, and "activity" could be set depending on whether the activity has been connected or not.

The check

      if (context instanceof Activity) {
        Activity activity = (Activity) context;
        if (showDialog != null && showDialog) {
          googleApiAvailability.showErrorDialogFragment(activity, connectionResult, REQUEST_GOOGLE_PLAY_SERVICES);
        }
      }

could then be replaced by "if (activity != null)".

[mvanbeusekom]

@ened thank you again for this issue report. I have already released a hotfix (version 2.0.3+hotfix.1) that should solve the NPE. I guess we were working simultaneously on a fix.

I see your PR includes some other changes as well (like a test which I am very excited about). Could you maybe merge the changes into your branch?

[ened]

@mvanbeusekom I can not see your changes in the develop branch?

[ened]

Just realised the changes are in master only. @mvanbeusekom - please rebase develop. (in the future, let's get rid of develop).

[mvanbeusekom]

@ened that is strange I developed the hotfix on the develop branch and pushed them there (see also commit 031f6da).

After that I merged them into master to prepare for the hotfix and made sure I pushed back the version bump to develop as well (see commit: 4515920).