How to create Android Handler in Java plugin

Questions & Answers
1

So, let’s say you have a Java plugin, you call into the Java plugin like so

private static readonly AndroidJavaClass m_somePlugin = new AndroidJavaClass("com.unity3d.Plugin.blah.SomePlugin");

using (var unityPlayer = new AndroidJavaClass("com.unity3d.player.UnityPlayer"))
{
    using (var currentActivity = unityPlayer.GetStatic<AndroidJavaObject>("currentActivity"))
    {
        m_somePlugin.CallStatic("onInitialise", currentActivity);
    }
}

and it looks something like this

public class SomePlugin 
{
    static public void onInitialise(final Activity currentActivity) 
    {
        Handler someHandler = new Handler();
    }
}

All quite simple. Except it will crash. Creating a Handler is the cause. I’m guessing it’s a thread issue.

So the question is, how does one create a handler in a Java plugin? Anyone know?

2

Yes, the solution to the problem was to use runOnUiThread. So in order to get the above code to not crash SomePlugin should look like so

public class SomePlugin 
{
    static public void onInitialise(final Activity currentActivity) 
    {
        currentActivity.runOnUiThread(new Runnable() {
            Handler someHandler = new Handler(); });
    }
}