Trying to create a simple AlertDialog plugin, crash occurs

I have a simple plugin written in Java that displays an alert dialog, like this:

Code (csharp):

1.  
2. public class TestAlert {
3.    
4.     public boolean dialogResult = false;
5.    
6.     public void ShowTestDialog( Activity activity ) {
7.         AlertDialog.Builder builder = new AlertDialog.Builder( activity );
8.         builder.setMessage( "This is a test" )
9.                 .setCancelable(false);
10.                 .setPositiveButton("Yes", new DialogInterface.OnClickListener() {
11.                     public void onClick(DialogInterface dialog, int id) {
12.                         dialogResult = true;
13.                         dialog.dismiss();
14.                     }
15.                 })
16.                 .setNegativeButton("No", new DialogInterface.OnClickListener() {
17.                     public void onClick(DialogInterface dialog, int id) {
18.                         dialogResult = false;
19.                         dialog.cancel();
20.                     }
21.                 });
22.         AlertDialog alert = builder.create();
23.         alert.show();
24.     }
25. }
26.  

I am then calling this function from Unity as follows:

Code (csharp):

1.  
2.     AndroidJNI.AttachCurrentThread();      // not sure if this is necessary or not, doesn't seem to make a difference
3.  
4.     var activity = new AndroidJavaClass( "com.unity3d.player.UnityPlayer" );
5.     var currentActivity = activity.GetStatic.<AndroidJavaObject>( "currentActivity" );
6.     var test = new AndroidJavaObject( "fractiv.test.TestAlert" );
7.     test.Call( "ShowTestDialog", currentActivity );
8.  

On the "ShowTestDialog" call, I get the following exception:

Code (csharp):

1.  
2. java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
3.  

Is this error occuring because I am not calling ShowTestDialog from the main thread? How can I fix this?

I am running Unity 3.4b3.

Thanks,
Sam McGrath

 

I just learned about Activity.runOnUiThread and also the 'post' function of messagequeue. I'm guessing one of these will fix my problem, but I won't be able to test it until I'm back in the office on Monday.

 

Yes, that should fix it, declare a

Code (csharp):

1. private Handler handler;

in your activity.

In the onCreate method of the activity:

Code (csharp):

1. handler = new Handler(this);

Let your activity implement Handler.Callback.

And then call from Unity a method in your activity that sends a message to the handler

Code (csharp):

1.  
2. handler.sendEmptyMessage(0);

In the implemented handleMessage method of your Activity you can deal with the message and finally change the UI:

Code (csharp):

1.  
2. public boolean handleMessage(Message msg) {
3.   if (msg.what == 0) {
4.      ...
5.   }
6. }
7.  

Ben

 

I got this working without having to extend the Activity at all. I just derived a Runnable class to house my code and parameters, then invoked it using runOnUiThread(). Works great!

 

Same, lost about a day before I worked the runOnUiThread out. The crash you get gives no clues at all