G4P Library - I cant't retrive the textfield value.

Hi I'm using the G4P library for a GUI inteface that must show some data coming via serial . I don't have problems to write value inside the texfield using data that are inside a byte[] using the below instructions:

String sonda_F1= str(char(inBuffer[42]))+str(char(inBuffer[44]))+str(char(inBuffer[46]))+str(char(inBuffer[48]));

textfield1.setPromptText(sonda_F1); **

I've problems when I try to read what I wronte inside the textfield1 as follow :

String my_datatxt = textfield1.getText();

println("My data :" my_datatxt);**

The output show just "My data :"

I've used the same method with a lable and lable11.getText() has worked fine , Where I'm wrong ?? :(

And another thing... assuming that I'm able to read the content of textfield1 and I got a value like this "1234", how can I split these in for different character to be store inside 4 location of a byte[] ?

Thanks since now for any suggestion ! :D