automatically update lookup search value

Hello, friends

Im finally able to move little bit forward with my custom lookup implementation. At the moment if I provide lookup code with a string value "3" (please see code in picture), build the project, and click on lookup in the dialog field it provides me with the results which contain number 3. However, at the moment Im trying to implement dynamic value passing. So I could type 3 in the field and it would give the results with 3, then in I type 5 it would give results which contain 5. I tried to pass the field.valueStr() (please see code in picture) but it doesnt seem to work. Do I need to implement another method to pass the field value dynamically? Which would it be and how to construct it? It would be nice if you could help me. As I understand there are lot of people trying to implement this. I will post whole code as a solution so others can learn from it.

Best regards,