负责创建一个用户界面，该界面具有一个包含菜单的顶栏。菜单应该有四个项目。首先将日期打印到对话框中，第二次将该日期写入 .txt 文件，第三次将框架背景颜色更改为绿色的随机色调，第四次退出。
除了 3 号之外，我的所有功能都正常工作。我已对其进行了设置，以便在您选择 colorItem MenuItem 时，menuBar 变为预定的绿色。
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.control.Alert.AlertType;
import java.util.Random;
import javafx.scene.control.Menu;
import javafx.scene.control.MenuBar;
import javafx.scene.control.MenuItem;
import javafx.scene.input.KeyCombination;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;
import java.time.LocalDate;
public class Main extends Application {
@Override
public void start(Stage stage) {
// Create MenuBar
MenuBar menuBar = new MenuBar();
// Create menus
Menu dateMenu = new Menu("Print");
Menu textMenu = new Menu("Write");
Menu colorMenu = new Menu("Change Color");
Menu exitMenu = new Menu("Options");
// Create MenuItems
MenuItem dateItem = new MenuItem("Date/Time");
MenuItem textItem = new MenuItem("Save To Text File");
MenuItem colorItem = new MenuItem("Random Color");
MenuItem exitItem = new MenuItem("Exit");
// Add menuItems to the Menus
dateMenu.getItems().addAll(dateItem);
textMenu.getItems().addAll(textItem);
colorMenu.getItems().addAll(colorItem);
exitMenu.getItems().addAll(exitItem);
// Add Menus to the MenuBar
menuBar.getMenus().addAll(dateMenu, textMenu, colorMenu, exitMenu);
// When user clicks on Date/Time MenuItem
dateMenu.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
LocalDate today = LocalDate.now();
Alert alert = new Alert(AlertType.INFORMATION);
alert.setTitle("Date Printer");
alert.setHeaderText(null);
alert.setContentText("Today's Date is: " + today);
alert.showAndWait();
}
});
// When user clicks on Save to Text File MenuItem
textMenu.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
LocalDate today = LocalDate.now();
try {
// Log message created
String content = "Button clicked on: " + today;
File file = new File("C:\\Users\\stca\\OneDrive - Episerver\\Desktop\\Week3.txt");
// File already created on desktop
if (!file.exists()) {
file.createNewFile();
}
FileWriter fw = new FileWriter(file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
bw.write(content);
bw.close();
System.out.println("Done");
} catch (IOException e) {
e.printStackTrace();
}
}
});
// When user clicks on Change Color MenuItem
colorMenu.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
menuBar.setStyle("-fx-background-color: #33cc33;");
}
});
// Set Accelerator for Exit MenuItem.
exitItem.setAccelerator(KeyCombination.keyCombination("Ctrl+X"));
// When user clicks on the Exit MenuItem
exitItem.setOnAction((EventHandler<ActionEvent>) new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
System.exit(0);
}
});
BorderPane root = new BorderPane();
root.setTop(menuBar);
Scene scene = new Scene(root, 400, 200);
stage.setTitle("JavaFX Menu for CSC372");
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
Application.launch(args);
}
}
如何让背景改变颜色而不是 menuBar？另外，我怎样才能调用不同色调的绿色随机化？我试过这个：
// When user clicks on Change Color MenuItem
colorMenu.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
Random random = new Random();
int r = random.nextInt();
int g = random.nextInt();
int b = random.nextInt();
Color randomColor = new Color(r, g, b);
menuBar.setStyle("-fx-background-color: randomColor");
}
});
但是我的 IDE 告诉我构造函数不可见。