How to listen resize event of Stage in JavaFX?

Question

I want to perform some functionality on resize event of form (or Scene or Stage whatever it is).

But how can I detect resize event of form in JavaFX?

Answer 1

You can listen to the changes of the widthProperty and the heightProperty of the Stage:

stage.widthProperty().addListener((obs, oldVal, newVal) -> {      // Do whatever you want });  stage.heightProperty().addListener((obs, oldVal, newVal) -> {      // Do whatever you want }); 

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Note: To listen to both width and height changes, the same listener can be used really simply:

ChangeListener<Number> stageSizeListener = (observable, oldValue, newValue) ->     System.out.println("Height: " + stage.getHeight() + " Width: " + stage.getWidth());  stage.widthProperty().addListener(stageSizeListener); stage.heightProperty().addListener(stageSizeListener);  

Answer 2

Keeping a fixed width to height ratio:

stage.minHeightProperty().bind(stage.widthProperty().multiply(0.5)); stage.maxHeightProperty().bind(stage.widthProperty().multiply(0.5));