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R0land013
R0land013

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Multiple Scenes JavaFX MVP

I made a demo about showing a way to create a multiple scene JavaFX application using MVP.

If you are not familiarized with MVP you should first understand it.
You can read about it here .

The source code is here.

About

I was finding a way to create a JavaFX application using only one window or stage, and
multiple scenes. The way I wanted to achieve it, was creating a mechanism to manage
the presenters using a stack. Doing that I could navigate between the presenters
and the scenes in a common manner, openig new pairs of presenter and view,
and being able to return to previous opened presenters.

And I wanted to got it without making a great effort in every presenter source code.

The Solution

Principal Classes and Interfaces

PresenterManager:

This is the most important class. It manage the transitions between presenters.
The presenters notify this class to add presenters or close them.

AbstarctPresenter:

All presenters must extends this class, because it defines the interfaces to
comunicate with the PresenterManager class. This class use notifyManagerToAddNewPresenter()
and notifyManagerToDeletePresenter() methods to achieve it. These method are protected.

PresenterView:

All views must implement this interface. It has the method getViewScene() to retrieve the
javafx.scene.Scene object from the view object. This method is used by
the PresenterManager to set the visible scene.

Explaining the mechanism

First, all presenters classes must extends the AbstarctPresenter class and implement
all abstract methods:

getDerivedPresenter(): is used by PresenterManager to retrieve a new presenter
to be opened. Inside this method you can use a switch statement or something similar to
return an instance of the wished presenter, because one presenter could open
different presenters. For example you could have an application which shows a window
with two button, the first to open a CRUD scene of products and the other a CRUD
scene of clients.

getPresenterView(): is used by PresenterManager to retrieve the PresenterView
of the presenter to be opened. And then get the javafx.scene.Scene from it.

Second, you have to implement methods which calls notifyManagerToAddNewPresenter()
and notifyManagerToDeletePresenter() to add new presenter and delete current presenter
respectively. See the source code of this project.

Third, in the views of your presenters you have to set the listeners in buttons or widgets
you want to fire the events of opening or closing presenters, and bind it with the methods created
in the previous step. And you have to implement the getViewScene() method to return the javafx.scene.Scene
from this view object. See the source code of this project.

Fourth, in the start(Stage) method of your Main class create an instance of PresenterManager
and set the initial presenter with setInitialPresenter(AbstarctPresenter). Then you can call the
show() method of AbstarctPresenter to show the stage or window of your application.

You can always check the source code of this project, if you did not understand this description.

Images of the demo

First scene

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Second Scene

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Third Scene

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