multithreading - JavaFX Wait for Page to Load Before Continuing -

i have method sets new web page webview's webengine needs wait until page has finished loading continue in current method.

essentially want:

mymethod() {     navigatetonewurl();     waitforpagetoload(); // part struggling     dosomethingelse(); } 

i have tried using changelistener() execute after method has finished executing. have googled many terms lead more frustration, "java non-blocking wait boolean". made far starting new threads (to prevent application gui locking up) , using countdowntimer ( opposed thread.join() ). following code umpteenth attempt @ getting whati want.

public static boolean pageloaded; public volatile static countdownlatch latch;  private static void testmethod() {     // set countdownlatch     latch = new countdownlatch(1);      // set page loaded flag     pageloaded = false;      // navigate new window     mywebview.getengine().load("https://www.google.com/");      // call method, starts thread, checks if page has loaded     waitforpageloaded();      // wait countdownlatch, latch     try { latch.await(); } catch (interruptedexception e) { /* todo auto-generated catch block */ e.printstacktrace(); }      // write result console     system.out.println("[pageloaded] " + pageloaded); }  private static void waitforpageloaded() {     thread thread = new thread()     {         public void run()         {             // 120 iterations * 250 ms = 30 seconds             (int = 0; < 120; i++)             {                 // check if page has loaded                 if (pageloaded == true)                 {                     break;                 }                 else                 {                     system.out.println("waited " + (i*250) + " milliseconds, far...");                     try { thread.sleep(250); }                     catch (interruptedexception e) { /* todo auto-generated catch block */ e.printstacktrace(); }                 }             }              // tell calling method move on life             latch.countdown();         }     } } 

and in .java file (class) have:

        // webengine , set listener state change         webengine webengine = webview.getengine();         webengine.getloadworker().stateproperty().addlistener         (             new changelistener<state>()             {                 public void changed(@suppresswarnings("rawtypes") observablevalue ov, state oldstate, state newstate)                 {                     if (newstate == state.succeeded)                     {                         // set page loaded flag                         otherclassname.pageloaded = true;                     }                 }             }         ); 

like ui frameworks, javafx based on event-driven model. behind scenes there loop runs (in fx application thread) processes events. should not deal directly loop.

you trying solve problem recreating loop , waiting condition, instead of registering handlers respond appropriate events. instead of waiting in thread (which thread? there's no obvious way this) page load, need respond each page completing loading , perform next step in test process. can registering listener on web engine's stateproperty.

so structure should like

public class myapp extends application {      private webview webview ;     private webengine engine ;      // variables representing current state of testing process...      @override     public void start(stage primarystage) {          webview = new webview();         engine = webview.getengine();          engine.getloadworker().stateproperty().addlistener((obs, oldstate, newstate) -> {             if (newstate == worker.state.succeeded) {                 // new page has loaded, process:                 testmethod();             }         });          // set ui etc...          engine.load(...); // load first page      }      private void testmethod() {         // check current state, next appropriate thing, update variables...     }  } 

this structure achieves trying - testmethod() invoked repeatedly, when each page has finished loading - "waiting" managed framework.