Android Plugin UnitySendMessage Never Called

Question

This was working a few weeks ago, but now I've noticed my OnReward message is no longer called from my custom plugin.

In my rewardcenter.cs class I call the plugin class to set the listener to the gameObject that this script is attached to (in this example case it's GameObject):

public class rewardcenter : MonoBehaviour {
    int counter = 0;
    void Start () {

        OnReward("85");
    }

    // Update is called once per frame
    void Update ()
    {
        if (counter == 20) {
            #if UNITY_ANDROID 
                PluginClass.SetRewardListener(gameObject.name);
                Debug.Log("Adding Android Reward Listener: " + gameObject.name);
            #endif
        }

        counter++;
    }

    void OnReward(string quantity)
    {
        Debug.Log("OnReward: " + quantity);
    }
}

In the PluginClass.cs file you can see how I call the setUnityObjectName call on the java plugin class to set the unity object to the passed in GameObject's name string GameObject:

private static AndroidJavaObject pluginClassInstance = null;
private static AndroidJavaObject activityContext = null;

// pass in the GameObject that implements the OnReward method
public static void SetRewardListener(string gameObjName)
{
    if (activityContext == null) {
        using (AndroidJavaClass activityClass = new AndroidJavaClass ("com.unity3d.player.UnityPlayer")) {
            activityContext = activityClass.GetStatic<AndroidJavaObject> ("currentActivity");
        }
    }

    using (AndroidJavaClass pluginClass = new AndroidJavaClass ("pluginclass.com.PluginClass")) {
        if (pluginClass != null) {
            pluginClassInstance = pluginClass.CallStatic<AndroidJavaObject> ("getInstance");
            activityContext.Call ("runOnUiThread", new AndroidJavaRunnable (() => {
                pluginClassInstance.Call("setUnityObjectName", gameObjName);
            }));
        }
    }
}

In the java PluginClass itself later on we attempt to call OnReward using UnitySendMessage on our game object:

   public void unityEarnedReward(String quantity) {
        Log.d(TAG, "unityEarnedReward: " + quantity);
        if (PluginClass.getInstance()._unityObjectName != null) {
            Log.d(TAG, "calling OnReward(" + quantity + ") on unityObject with name: " + PluginClass.getInstance()._unityObjectName);
            com.unity3d.player.UnityPlayer.UnitySendMessage(PluginClass.getInstance()._unityObjectName, "OnReward", quantity);
        }
    }

I end up with a log output in Android Studio of:

calling OnReward(202) on unityObject with name: GameObject

But it never seems to actually call OnReward within the game.

Just for kicks I tried calling OnReward when the script starts, it ends up with an output of:

OnReward: 85

So I know it works and prints to the console when it is executed.

Any idea where I'm going wrong? The weird thing is this worked a few weeks ago, but now the OnReward method isn't executed.

EDIT:

I also tried running it without the specific class declaration like this with no luck:

UnityPlayer.UnitySendMessage(PluginClass.getInstance()._unityObjectName, "OnReward", quantity);

I also renamed my gameObject to be MyCustomPlugin but while the android code triggered it doesn't seem the OnReward method was ever triggered on the script linked to MyCustomPlugin.

Screenshot of script:

When I run this code:

void Update ()
    {
        var unityPlayer = new AndroidJavaClass ("com.unity3d.player.UnityPlayer");
        unityPlayer.CallStatic ("UnitySendMessage", gameObject.name, "OnReward", "185");

        OnReward ("86"); 
    }

I end up with two Log messages:

04-14 10:47:47.085 10341-10354/? I/Unity: OnReward: 86

                                          (Filename: ./artifacts/generated/common/runtime/DebugBindings.gen.cpp Line: 51)
04-14 10:47:47.095 10341-10354/? I/Unity: OnReward: 185

                                          (Filename: ./artifacts/generated/common/runtime/DebugBindings.gen.cpp Line: 51)

Answer 1

It seems the fundamental problem is that because I have a separate activity, it pauses the UnityActivity which in turn pauses Unity.

Thus Unity cannot receive the UnitySendMessage when I was trying to send it.

To get around this I implemented a way to call it in my onStop method of my Activity. At this point Unity is no longer paused and can receive the message.