How to consume JavaFX TouchEvent correctly? - user-interface

Question

I have a GUI with several menus.
The current menu is the child of a StackPane which in turn is a child of a RootLayout (GridPane) and there is only one menu active at a time which means that the StackPane has only one child at a time.
The menu switches by replacing all children in the StackPane with the new page.
(theStackpane.getChildren().setAll(newMenu);)
The active menu may have a button that changes the menu, so a click on the button replaces all children in the StackPane (the one with the button you just clicked as well).
The problem is, when there is a button that changes the menu and there is a button at the same location in the new menu, both buttons get clicked, although you just clicked the first button (which changes the menu).
The structure is like this:
RootLayout
.theStackPane
..activeMenu
...oneButton
A click on oneButton (that changes the menu) leads to:
RootLayout
.theStackPane
..newMenu
...twoButton
The StackPane stays the same, just all children of theStackPane get exchanged by new ones.
Now if oneButton is at the same location of twoButton, oneButton gets activated, changes the menu by replacing all children, newMenu is shown, twoButton gets activated and does whatever it does - stop.
Although I'd like to have it like this:
If oneButton is at the same location of twoButton, oneButton gets activated, changes the menu by replacing all children, newMenu is shown - stop.
How do I prevent the current behaviour?

Answer 1

buttonOne & buttonOnNewPage are inside the same stackPane, right? Then that happens because in the event capturing phase the stackPane propagates the event to both buttons so when the handler tries to consume it, it has already been propagated.
So, instead of using a handler in buttonOne lets try using a filter, and inside it consuming the event. Try something like this:
EventHandler filter = new EventHandler(<TouchEvent>() {
public void handle(TouchEvent event) {
theStackPane.getChildren().setAll(newPage);
event.consume();
}
}
buttonOne.addEventFilter(TouchEvent.TOUCH_PRESSED, filter);

Answer 2

I finally got to a solution:
I got it to work as expected when I switched setOnTouchPressed to setOnAction.
I don't event need to consume the ActionEvent when I touch oneButton.
So instead of
oneButton.setOnTouchPressed(e -> {
theStackPane.setAll(newPage);
});
I am now using
oneButton.setOnAction(e -> {
theStackPane.setAll(newPage);
});