Java Question Events do not raise in a class but in Main-module it is working

[moster67]

I am bit stuck with an issue regarding raising events:

I have the following Java-code for raising the event:

    private void addVideoOutputEvents() {
        player.getMp().addMediaPlayerEventListener(new MediaPlayerEventAdapter() {

            @Override
            public void timeChanged(MediaPlayer mediaplayer, long newTime){
                if (ba.subExists(eventName + "_time")) {
                    ba.raiseEvent(B4JVlcj.this, eventName + "_time", new Object[] { newTime });
                 
//                      Tests
//                    ba.raiseEventFromDifferentThread(B4JVlcj.this, null, 0, eventName + "_time", false, new Object[] {newTime});
//                    ba.raiseEvent2(B4JVlcj.this,false,eventName + "_time", false,new Object[] {newTime});
//                    ba.raiseEventFromUI(B4JVlcj.this, eventName + "_time", new Object[] { newTime });
                }
            }
        });

    }

The event raises just fine in B4J when I use the library directly in Main but if I make a B4J-Class where I call the library, the event will not fire in the Class and obviously the event will not fire in Main.
However, all method-calls (and properties) work just fine so I know that the target-module is correct.

This is the event and callback in Class-code:

Private Sub vlc_Time (NewTime As Long)
    'callbacks
    Log(NewTime)
    If SubExists(mModule, event & "_Time") Then
        CallSub2(mModule, event & "_Time", NewTime)
    End If
End Sub

and here is the event in Main:

Sub vlc1_Time (NewTime As Long)
    Log("Current time is " & NewTime)
End Sub

Any ideas?

 

[DonManfred]

The differents in the eventname is known and you are aware of?
In main the eventname is set to vlc1
In the class vlc

I ust want to make sure you are aware of the little difference... If you are using identical codes then i would have expected vlc in both.

 

[moster67]

I don't think that is the problem. The idea using a Class is that I can create more than one instance of VLC in a simple way with some utility methods in the class.

In my class-code:

Public Sub Initialize(module As Object, eventname As String)
 
    'setting class globals
    mModule = module
    event = eventname
 
    vlc.Initialize(eventname)

End Sub

which I initialize from Main as follows:

'AppStart
vlc1.Initialize(Me, "vlc1")
'vlc2.Initialize(Me, "vlc2")

'event
Sub vlc1_Time (NewTime As Long)
Log("Current time is " & NewTime)
End Sub

Using two instances of VLC in Main (without using a class) works just fine.

I must be doing something really stupid....

 

[moster67]

It should be said that I have never written my own classes in B4J (or B4A) so maybe I am missing something...

 

[JordiCP]

Don't know in B4J but in B4A from inline Java (inside a class) this works

   ba.raiseEvent(null, eventName + "_time", new Object[] { newTime });

 

[moster67]

I tried that @JordiCP but it did not work.

By logging, I noted that my event in my Java-code is triggered but the eventName is wrong - it is "vlc1" and not "vlc" and logically the event in not found in my class since I initialize the instance from the class with "vlc". So I guess @DonManfred is correct.

So it seems like I cannot use a Class to initialize more than one instance of the VLC-object from Main. I am wondering if I need /can rewrite the logic of the Java-wrapper to handle it...

 

[moster67]

So it seems like I cannot use a Class to initialize more than one instance of the VLC-object from Main

On seconds thoughts, the methods are working and clearly distinguishes between different instances and the Java-wrapper knows which instance to handle.
It seems to happen only with the events (and the eventName).
I guess I am too tired to think clear. Better try again in a few days..

 

[JordiCP]

Second try using reflection. I have made a small example for myself and adapted to this case. Should work except for syntax errors.

You will need to keep an instance of the class from where the VLC-object is created

import java.lang.reflect.Method;     // add 

Object myInstance;                     // add to your class globals

public void SetEventTarget(Object mInstance){   // add this method or add this parameter to the the initializer
  myInstance=mInstance;
}

private void addVideoOutputEvents() {

  player.getMp().addMediaPlayerEventListener(new MediaPlayerEventAdapter() {

    @Override
    public void timeChanged(MediaPlayermediaplayer, long newTime){

      try{
        Method m = myInstance.getClass().getMethod("_"+eventName+"_time", long.class);
        Object result = m.invoke( myInstance, new Object[] { newTime });     
      }
      catch (Exception e) {
      }
    }
  });
}

...and, from the B4A class where you instantiate your VLC1_object...

  ...
  VLC1.initialize2(......., Me)      'add instance to the initializer
  'or 
  VLC1.SetEventTarget(Me)      'a separate method
  ...
[CODE]

 

[moster67]

I finally found some time to look into this further. I tried your suggestion but I couldn't get it to work although I might have not understood your suggestion fully.

Anyway, since it is the evenname which is the problem, I resolved it by adding another argument to the initialize method which corresponds to the name of the instance of the vlc-object declared in the B4A class. In this way, the events are raised properly in the B4A-class and thus also in the main-class. I created also a second initialize method for the original code which already works fine with the eventname and when vlc is used directly in main (and not in a class).

I am still unsure if this is the correct way but all events are now raised properly and the events trigger fine from 2 separate vlc-objects at the same time so this has to do for now.

 

[JordiCP]

I am still unsure if this is the correct way

Well, if it does exactly what you want, then it is the correct way (yes, I know this is not always true)

I will try my solution in my library (haven't done it yet) , since your post has made think that, as I have it implemented now, also it will only work with main.