import javafx.scene.control.Button; //导入方法依赖的package包/类

private void buildMainMenu(Group root, Scene scene, Dimension screenSize) {

// Main title

Label maintitle = new Label();

maintitle.setText("Chess Master");

maintitle.setFont(new Font("Arial", MAIN_TITLE_FONT_SIZE));

maintitle.setLayoutX(MAIN_TITLE_LEFT_PADDING);

maintitle.setLayoutY(MAIN_TITLE_TOP_PADDING);

root.getChildren().add(maintitle);

// Buttons

Group buttonsGroup = new Group();

// Start button.

Button choiceGameButton = new Button();

choiceGameButton.setLayoutX(screenSize.getWidth() * BUTTON_LEFT_PADDING);

choiceGameButton.setLayoutY(maintitle.getLayoutY() * 2);

choiceGameButton.setPrefSize(BUTTONS_WIDTH, BUTTONS_HEIGHT);

choiceGameButton.setText("Choose your game");

buttonsGroup.getChildren().add(choiceGameButton);

// Setting button.

Button settingButton = new Button();

settingButton.setLayoutX(screenSize.getWidth() * BUTTON_LEFT_PADDING);

settingButton.setLayoutY(choiceGameButton.getLayoutY() + BUTTONS_SPACE);

settingButton.setPrefSize(BUTTONS_WIDTH, BUTTONS_HEIGHT);

settingButton.setText("Settings");

buttonsGroup.getChildren().add(settingButton);

// Quit button.

Button quitButton = new Button();

quitButton.setLayoutX(screenSize.getWidth() * BUTTON_LEFT_PADDING);

quitButton.setLayoutY(settingButton.getLayoutY() + BUTTONS_SPACE);

quitButton.setPrefSize(BUTTONS_WIDTH, BUTTONS_HEIGHT);

quitButton.setText("Quit game");

quitButton.setOnAction(handle -> closeApp());

buttonsGroup.getChildren().add(quitButton);

root.getChildren().add(buttonsGroup);

// Copyright

Label copyright = new Label();

copyright.setText("All rights reserved, Nicolas GILLE, 2017");

copyright.setFont(new Font("Arial", 12));

copyright.setLayoutX(COPYRIGHT_LEFT_PADDING);

copyright.setLayoutY(COPYRIGHT_TOP_PADDING);

root.getChildren().add(copyright);

}