Wait until any button is pressed? - button

Question

I am writing a TicTacToe game in JavaFX. I've decided to make a board as 9 (3x3) buttons with changing text: "" (if empty) or "X" or "O". Everything is going ok beside one thing... I got stuck here:
public void game() {
while(keepPlaying) {
if(computerTurn) {;
computerMove();
}else {
while(waitForUser) {
//wait until any of 9 buttons is pushed!
}
}
if (checkResult()) {
keepPlaying = false;
}
computerTurn = !computerTurn;
}
}
How to wait for user pushing any of those 9 buttons and then continue with computer turn??
I need something like waiting for scanner input in console application, but this input must be one of 9 buttons...
I know that there are few "possible duplicates", but in fact those problems were solved using methods I can't use here, for example timer. Correct me if I am wrong.

Answer 1

Blocking the application thread in JavaFX should not be done since it freezes the UI. For this reason a loop like this is not well suited for a JavaFX application. Instead you should react to user input:
public void game() {
if (keepPlaying && computerTurn) {
computerMove();
if (checkResult()) {
keepPlaying = false;
}
computerTurn = false;
}
}
// button event handler
private void button(ActionEvent event) {
if (keepPlaying) {
Button source = (Button) event.getSource();
// probably the following 2 coordinates are computed from GridPane indices
int x = getX(source);
int y = getY(source);
// TODO: update state according to button pressed
if (checkResult()) {
keepPlaying = false;
} else {
computerMove();
if (checkResult()) {
keepPlaying = false;
}
}
}
}
Starting with javafx 9 there is a public API for "pausing" on the application thread however:
private static class GridCoordinates {
int x,y;
GridCoordinates (int x, int y) {
this.x = x;
this.y = y;
}
}
private final Object loopKey = new Object();
public void game() {
while(keepPlaying) {
if(computerTurn) {
computerMove();
} else {
// wait for call of Platform.exitNestedEventLoop​(loopKey, *)
GridCoordinates coord = (GridCoordinates) Platform.enterNestedEventLoop​(loopKey);
// TODO: update state
}
if (checkResult()) {
keepPlaying = false;
}
computerTurn = !computerTurn;
}
}
private void button(ActionEvent event) {
if (keepPlaying) {
Button source = (Button) event.getSource();
// probably the following 2 coordinates are computed from GridPane indices
int x = getX(source);
int y = getY(source);
Platform.exitNestedEventLoop​(loopKey, new GridCoordinates(x, y));
}
}