如何从 AnimationTimer 对象获取特定字段？

Question

I've written a simple game using JavaFX for the GUI and AnimationTimer for the game itself, but I've found that any fields that update within the AnimationTimer object can't be found outside of the object. I've managed to continuously record how long a game runs, and the score of that game, but can't find a way to get these values out of the AnimationTimer object so I can add them to my GUI.

I've already tried java.lang.Reflect, but I can't seem to get it to work.

AnimationTimer animations = new AnimationTimer() //creates animations
{
    @Override
    public void handle(long now) 
    {       
        //update frames           
        if(jump == 0) //moves the player model to the starting position
        {
            playerY = 160;               
        }

        else if(jump == 1) //moves the player model up (jumping)
        {
            playerY = 100;              
        }

        if(shout == 1) //makes player immune while "shouting"
        {
            player.setFill(Color.GREEN);
        }

        if(shout == 0) //makes player not immune anymore
            player.setFill(Color.BLUE);

        if(obstacleX == PLAYER_X) //updates the score
        {
            points += 10;   
            score.setText("Score: " + String.valueOf(points));
        }

        if(player.getBoundsInParent().intersects(obstacle.getBoundsInParent())) //detects if the player model touches an obstacles
        {
            if(obstacle.getEndY() == 0)
            {
                if(player.getFill() == Color.BLUE)   
                    player.setFill(Color.RED);  
            }

            else if(obstacle.getEndY() == 130)
                player.setFill(Color.RED);       
        }

        if(obstacleX > 0) //moves the obstacles' reference point from the right to the left
            obstacleX -= 5;

        if(obstacleX == 0)
        {
            obstacleX = 400;  
            int[] array = new int[]{0, 0, 130};
            Random randomNum = new Random();
            int i = randomNum.nextInt(array.length);
            random = array[i];
            obstacle.setEndY(random);
        }

        //render frames
        player.setCenterY(playerY); 
        obstacle.setStartX(obstacleX); //this and line 110 move the obstacle across the scene
        obstacle.setEndX(obstacleX);

        try{ //exception handler for outputs      

            if(player.getFill() == Color.GREEN)
            {
                digitalOutput6.setDutyCycle(1); //turns on green LED
                digitalOutput0.setDutyCycle(0);
            }

            if(player.getFill() == Color.BLUE)
            {
                digitalOutput6.setDutyCycle(0); //turns off LEDs
                digitalOutput0.setDutyCycle(0);
            }  

            if(player.getFill() == Color.RED) //stops the animation when the player model reacts to touching an obstacle
            {
                endTime = System.currentTimeMillis() - startTime; 
                finalScore = score.getText();
                this.stop(); //ends game                             
                gameOver = 1;              
                digitalOutput0.setDutyCycle(1); //turns on red LED
                digitalOutput6.setDutyCycle(0);
                gameStage.setScene(gameEnd); //establishing scene
                gameStage.setTitle("Game Over"); 
                gameStage.show();                                   
            }          
        } //end of try block

        catch(PhidgetException e)
        {
            System.out.println("Phidget Output Error");
        }                              
    } //end of animation handle itself                                                            
};    //end of animation method 

I tried using

long finalTime = animations.getLong(endTime);

and

String endScore = animations.getField(finalScore);

But no luck. Any help appreciated.

Answer 1

AnimationTimer itself doesn't expose any attributes, make a custom class which wraps an AnimationTimer object in it, and save any attributes you want to access.

When you initialize the custom class, initialize the AnimationTimer object and override the function (as what you've done), also updates whatever attributes you want to expose.

I am not familiar with javafx, there might be other better ways, this is the one quick solution I can think of.

Did a quick search, these examples might be helpful:
https://netopyr.com/2012/06/14/using-the-javafx-animationtimer/
https://tbeernot.wordpress.com/2011/11/12/javafx-2-0-bubblemark/

Answer 2

First of all do not use Reflections on Anonymous classes It will work but will cause a lot of ineffeciency and dirty code. Second of all, you try to acces fields which are in the Methodscope of handle(long now) not in the Class scope.

        AnimationTimer t = new AnimationTimer() {
            int fieldInt = 0; // would be accessible
            @Override
            public void handle(long now) {
                //do something

            }
        };

        AnimationTimer t = new AnimationTimer() {

            @Override
            public void handle(long now) {
                int fieldInt = 0; // is not accessible as regular field
                //do something

            }
        };

What you can do is the following:

Use a class that extends a Animationtimer

public class Scheduler extends AnimationTimer{

    private int gameEnd = 42;
    private String someValue = "hello";

    @Override
    public void handle(long now) {

        gameEnd += 1;

        if(gameEnd >= 1000000) {
            someValue ="Bye bye";
        }
    }

    public String getSomeValue() {
        return someValue;
    }

here you can use:

Scheduler s = new Scheduler();

s.start();

//whatever you want to do

System.out.Println(s.getSomeValue());

or when you want to use the Anonymous class approach, you should create a Property that is outside of AnimationTimer and use it. (Wich is a thing that I would prefer, because you can have a changeListener on the Property and recieve a callback when the value is changed)

    public void whateverMethod() {

        SimpleIntegerProperty gameEndProp = new SimpleIntegerProperty(42);
        AnimationTimer t = new AnimationTimer() {

            @Override
            public void handle(long now) {
                gameEndProp.set(gameEndProp.get()+1);

            }
        };

        t.start();
        //Do something
        System.out.println(gameEndProp.get());

    }