java - 如何在同一个窗口中依次打开2个类(class)

Question

我正在使用 NetBeans IDE 在 javafx 中开发一个项目。我也是javafx新手。我几乎创建了所有的类。现在我正在尝试将它们联系起来。我的意思是，当从一个类按下按钮时，其他类的功能应该起作用。我需要将该功能显示在同一窗口上。我将在这里提供我的一个类(class)的代码。我没有在此处包含导入语句和其他不必要的代码部分:

package login;

public class Login extends Application {

TextField t1,t2,t4,t5;
PasswordField t3;
ComboBox comboBox1,comboBox2,comboBox3;

private Connection connect = null;
private Statement statement = null;
private PreparedStatement preparedStatement = null;

@Override
public void start(Stage stage) {

    BorderPane border = new BorderPane();

    border.setTop(loginHBox1());
    border.setLeft(loginVBox1());
    border.setRight(loginVBox2());

    Scene scene = new Scene(border,700,550);
    stage.setScene(scene);
    stage.setResizable(false);
    scene.getStylesheets().add
    (Login.class.getResource("Login.css").toExternalForm());
    stage.show();
}

private HBox loginHBox1() {

    HBox hbox = new HBox();
    hbox.setPadding(new Insets(15, 12, 10, 180));
    hbox.setSpacing(10);

    Label lb1=new Label("LOG IN OR CREATE NEW ACCOUNT");
    lb1.setAlignment(Pos.CENTER);
    lb1.setFont(Font.font("Calibri",FontWeight.BOLD,26));
    lb1.setTextFill(Color.BLACK);

    hbox.getChildren().addAll(lb1);

    return hbox;
}

private VBox loginVBox1() {

    VBox vbox = new VBox();
    vbox.setPadding(new Insets(20,30,15,50));
    vbox.setSpacing(10);

    Label lb3=new Label("LOG  IN");
    lb3.setAlignment(Pos.CENTER);
    lb3.setFont(Font.font("Calibri",FontWeight.BOLD,24));
    lb3.setTextFill(Color.BLACK);

    Label lb1=new Label("Username");
    lb1.setAlignment(Pos.CENTER);
    lb1.setFont(Font.font("Calibri",FontWeight.BOLD,16));
    lb1.setTextFill(Color.BLACK);

    TextField t11=new TextField();
    t11.setPrefSize(150,30);

    Label lb2=new Label("Password");
    lb2.setAlignment(Pos.CENTER);
    lb2.setFont(Font.font("Calibri",FontWeight.BOLD,16));
    lb2.setTextFill(Color.BLACK);

    PasswordField pw11=new PasswordField();
    pw11.setPrefSize(150,30);

    Button b1=new Button("LOG IN");
    b1.setFont(Font.font("Calibri",FontWeight.BOLD,16));
    b1.setPrefSize(80,5);

    btnl2.setOnAction(new EventHandler<ActionEvent>() {
     @Override
     public void handle(ActionEvent e) {
      // THIS IS THE PART WHERE AM CALLING THE FUNCTION OF OTHER CLASS. WHICH FUNCTION
      // SHOULD I CALL HERE ?
     }
     });

    vbox.getChildren().addAll(lb3,lb1,t11,lb2,pw11,b1);

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

现在我将提供其他类的代码。这里也不包括整个代码。

package userpage;

public class UserPage extends Application {

TextField t1,t3,t4;
ComboBox comboBox1;

private Connection connect = null;
private Statement statement = null;
private PreparedStatement preparedStatement = null;

@Override
public void start(Stage stage) {

    BorderPane border = new BorderPane();

    HBox hbox = addHBox1();
    border.setTop(hbox);
    border.setRight(addVBox1());
    border.setLeft(addVBox2());
    border.setBottom(addHBox2());

    Scene scene = new Scene(border,700,450);
    stage.setScene(scene);
    stage.setResizable(false);
    scene.getStylesheets().add
    (UserPage.class.getResource("UserPage.css").toExternalForm());
    stage.show();
}

private HBox addHBox1() {

    HBox hbox = new HBox();
    hbox.setPadding(new Insets(15, 12, 15, 280));
    hbox.setSpacing(10);   // Gap between nodes

    Label lb1=new Label("HOME PAGE");
    lb1.setAlignment(Pos.CENTER);
    lb1.setFont(Font.font("Trebuchet MS",FontWeight.BOLD,22));
    lb1.setTextFill(Color.BLUEVIOLET);

    hbox.getChildren().addAll(lb1);

    return hbox;
}

private VBox addVBox1() {

    VBox vbox = new VBox();
    vbox.setPadding(new Insets(20,40,30,4)); 
    vbox.setSpacing(10);

    MenuBar menuBar = new MenuBar();

    Menu menuFile1 = new Menu("ADD");
    Menu menuFile2 = new Menu("EDIT");
    Menu menuFile3 = new Menu("VIEW");
    Menu menuFile4 = new Menu("HELP");

    MenuItem add1 = new MenuItem("ENTER STUDENT DETAILS");
    MenuItem add2 = new MenuItem("ENTER C-MARK");
    MenuItem add3 = new MenuItem("ENTER ATTENDANCE");

    MenuItem add4 = new MenuItem("EDIT STUDENT DETAILS");
    MenuItem add6 = new MenuItem("EDIT C-MARK");
    MenuItem add8 = new MenuItem("EDIT ATTENDANCE");

    MenuItem add10 = new MenuItem("STUDENT DETAILS");
    MenuItem add11 = new MenuItem("C-MARK");
    MenuItem add12 = new MenuItem("ATTENDANCE");

    MenuItem add13 = new MenuItem("VIEW HELP");        

    menuFile1.getItems().addAll(add1,add2,add3);
    menuFile2.getItems().addAll(add4,add6,add8);
    menuFile3.getItems().addAll(add10,add11,add12);
    menuFile4.getItems().addAll(add13);
    menuBar.getMenus().addAll(menuFile1,menuFile2,menuFile3,menuFile4);

    vbox.getChildren().addAll(menuBar);

    return vbox;

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

}

Answer 1

在 JavaFX 应用程序中，您应该只有一个扩展 Application 的类。如果 UserPage 应该是一个 UI 组件，为什么不将其设为所提供 Pane 之一的子类(例如 AnchorPane、BorderPane 等)。对于你的情况

public class UserPage extends BorderPane{

    TextField t1,t3,t4;
    ComboBox comboBox1;

    private Connection connect = null;
    private Statement statement = null;
    private PreparedStatement preparedStatement = null;

    public UserPage(){
      this.setTop(addHBox1());
      this.setRight(addVBox1());
      this.setLeft(addVBox2());
      this.setBottom(addHBox2());
    }

    //.... Your methods
} 

对我来说似乎最合理。从UserPage 中删除Scene 相关代码。它不属于那里。使用修改后的 UserPage 类，如果您想在以下位置打开 UserPage，则 Login 类中的 EventHandler 可以包含此代码同一个窗口。

btnl2.setOnAction(new EventHandler<ActionEvent>() {
 @Override
 public void handle(ActionEvent e) {
  ((Stage)btnl2.getScene().getWindow()).setScene(new Scene(new UserPage()));
 }
 });

如果您想在另一个窗口中打开 UserPage，则可以这样做。

btnl2.setOnAction(new EventHandler<ActionEvent>() {
 @Override
 public void handle(ActionEvent e) {
     Stage usrpagestage = new Stage();
     usrpagestage.setScene(new Scene(new UserPage()));
     ((Stage)btnl2.getScene().getWindow()).close();
     usrpagestage.show();
 }
 });

如果您的 Login 类也应该是一个 UI 组件，那么它不应该扩展 Application 而应该扩展所提供的 Pane 之一。例如

public class Login extends GridPane{ .... }

您的应用程序启动可能如下所示

public class Main extends Application{

    @Override
    public void start(Stage stage) throws Exception {
        stage.initStyle(StageStyle.UTILITY);
        stage.setResizable(false);
        Login loginview = new Login();
        Scene scene = new Scene(loginview, 400, 200);
        stage.setScene(scene);
        stage.show();       
    }

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

我认为会更干净。