我正在尝试用javafx制作一个记忆游戏，它工作得很好，当你发现两张相同的图片时，它会告诉你，但是我怎样才能让它在整个游戏中一直显示匹配的图片呢？因为当你不匹配的时候，如果你匹配的话，图片就会隐藏起来。我想不出一个办法，让按钮在你得到匹配后继续显示图片。

public void start(Stage primaryStage) {
        ArrayList<String> list = new ArrayList<>();
        int userInput = 4;
        imageWithLoc = new String[userInput][userInput];
        btnArr = new Button[userInput][userInput];
        int targetNum = ((userInput * userInput) / 2);
        int count = 0;
        int count2 = 0;
        while (count < targetNum) {
            int numC = (int) (Math.random() * userInput);
            int numR = (int) (Math.random() * userInput);
            if (imageWithLoc[numC][numR] == null) {
                if (!list.contains(images[count])) {
                    imageWithLoc[numC][numR] = images[count];
                    list.add(images[count]);
                    count++;
                }
            }
        }
        for (int i = 0; i < userInput; i++) {
            for (int j = 0; j < userInput; j++) {
                if (imageWithLoc[i][j] == null) {
                    imageWithLoc[i][j] = images[count2];
                    count2++;
                }
            }
        }

        for (int i = 0; i < userInput; i++) {
            for (int j = 0; j < userInput; j++) {
                System.out.println(imageWithLoc[i][j] + " ");
            }
        }
        for (int i = 0; i < userInput; i++) {
            for (int j = 0; j < userInput; j++) {

                Button btn = new Button();
                btn.setPrefSize(250, 250);
                btnArr[i][j] = btn;
                Image img1 = new Image(imageWithLoc[i][j], 250, 250, true, true);
                String strImg = imageWithLoc[i][j];
                btn.setOnAction(e -> {
                    ImageView iv1 = new ImageView();
                    iv1.setImage(img1);
                    btn.setGraphic(iv1);
                    if (firstImg == null) {
                        firstImg = strImg;
                        firstBtn = btn;
                    } else if (secondImg == null) {
                        secondImg = strImg;
                        secondBtn = btn;
                    } else if (firstImg != null && secondImg != null) {
                        firstImg = strImg;
                        secondImg = null;
                        secondBtn.setGraphic(null);
                        firstBtn.setGraphic(null);
                        firstBtn = btn;
                        secondBtn = null;
                    }
                    if (firstImg.equals(secondImg)) {
                        System.out.println("match");
                    }
                });
                btnGp.add(btn, j, i);
                btnGp.setHgap(10);
                btnGp.setVgap(10);
                btnGp.setPadding(new Insets(10, 10, 10, 10));
            }
        }

        bp.setCenter(btnGp);
        Scene scene = new Scene(bp, 1000, 1000);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}