java - Using a ToggleButton with a while loop JavaFX -

i'm making javafx application has toggle button. want while loop run long button toggled , stop when button toggled off. right in program, while loop activates when press button loop not stop when toggle off button. there i'm missing make loop stop when toggle off button?

import java.util.hashmap; import java.util.map; import java.util.concurrent.atomic.atomicboolean;  import javafx.application.application; import javafx.scene.scene; import javafx.scene.control.togglebutton; import javafx.scene.layout.borderpane; import javafx.stage.stage;  public class main extends application{      private borderpane layout;     private scene scene;       togglebutton button = new togglebutton("button");     atomicboolean running = new atomicboolean();      public static void main(string[] args) {         launch(args);     }      @override     public void start(stage window) throws exception {         layout = new borderpane();         scene = new scene(layout, 450, 80);            button.setonaction(e -> robot());          layout.setcenter(button);           window.settitle("desktop app");         window.setscene(scene);         window.show();      }      public void robot() {           map<integer, character> keymap = new hashmap();          running.set(button.isselected());          keymap.put(1, 'a');         keymap.put(2, 'b');         keymap.put(3, 'c');         keymap.put(4, 'd');         keymap.put(5, 'e');         keymap.put(6, 'f');         keymap.put(7, 'g');         keymap.put(8, 'h');         keymap.put(9, 'i');         keymap.put(10, 'j');         keymap.put(11, 'k');         keymap.put(12, 'l');         keymap.put(13, 'm');         keymap.put(14, 'n');         keymap.put(15, 'o');         keymap.put(16, 'p');         keymap.put(17, 'q');         keymap.put(18, 'r');         keymap.put(19, 's');         keymap.put(20, 't');         keymap.put(21, 'u');         keymap.put(22, 'v');         keymap.put(23, 'w');         keymap.put(24, 'x');         keymap.put(25, 'y');         keymap.put(26, 'z');         keymap.put(27, ' ');         keymap.put(28, '0');         keymap.put(29, '1');         keymap.put(30, '2');         keymap.put(31, '3');         keymap.put(32, '4');         keymap.put(33, '5');         keymap.put(34, '6');         keymap.put(35, '7');         keymap.put(36, '8');         keymap.put(37, '9');          if(running.get()) {             while(running.get()) //only runs when button has been toggled             {                 int randomint = (int )(math.random() * 37 + 1);                 system.out.println(keymap.get(randomint));              }         }               //while button toggled                 //choose random integer                 //map random integer key on keyboard                 //robot presses key on focused window     } } 

running while loop on fx application thread block thread, means no more interaction gui possible.

the condition of while loop never change, because of selectedproperty of togglebutton never change execution never exits while loop.

you use service execute loop on background thread have gui responsive when loop runs. services can canceled , restarted.

example

the following example creates service runs task executes while loop until service gets cancelled.

i listen changes of selectedproperty of togglebutton:

• if selected: service reseted , started

• if not selected: service gets cancelled

code

togglebutton toggle = new togglebutton();  service<void> toggleservice = new service<void>() {      @override     protected task<void> createtask() {          return new task<void>(){              @override             protected void call() throws exception {                  while(!iscancelled()) {                     int randomint = (int )(math.random() * 37 + 1);                     system.out.println(randomint);                 }                 return null;             }         };     } };  toggle.selectedproperty().addlistener((obs, oldval, newval) -> {     if(newval) {         toggleservice.reset();         toggleservice.start();     }     else          toggleservice.cancel();  });