javafx fxml程序错误（没有main方法）

Question

我对 javafx 和 fxml 还很陌生。我正在努力自学！但是，当我为简单的登录 GUI 创建程序时，当我最终尝试运行我的程序时遇到了问题。它告诉我 class 中没有主要方法，我不确定如何修复它。有什么想法吗？

我的程序创建了一个登录屏幕，当您输入 "test" 作为用户名和密码时，它将带您到另一个场景。

这是我的Login.java

package com;

    import javafx.application.Application;
    import javafx.fxml.FXMLLoader;
    import javafx.stage.Stage;
    import javafx.scene.Parent;
    import javafx.scene.Scene;

    /**
     *
     * @author Tyler
     */
    public class Login extends Application{

        @Override
        public void start(Stage stage) throws Exception {
            Parent root = FXMLLoader.load(getClass().getResource("Login.fxml"));
            Scene scene = new Scene(root);
            stage.setScene(scene);
            stage.setTitle("Login");
            stage.show();
        }

    }

这是我的LoginController.java

package com;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.stage.Stage;

/**
 * FXML Controller class
 *
 * @author Tyler
 */
public class LoginController implements Initializable {

    @FXML
    private Label lblMessage; 
    @FXML
    private TextField txtUsername;
    @FXML
    private PasswordField txtPassword;
    @FXML
    private void btnLoginAction(ActionEvent event) throws Exception{
        if(txtUsername.getText().equals("test") && txtPassword.getText().equals("test")){
            ((Node) (event.getSource())).getScene().getWindow().hide();
            Parent parent = FXMLLoader.load(getClass().getResource("DateSelection.fxml"));
            Stage stage  = new Stage();
            Scene scene = new Scene(parent);
            stage.setScene(scene);
            stage.setTitle("Date Selection");
            stage.show();
        }else{
            lblMessage.setText("Username or Password is invalid!");
        }
    }
    /**
     * Initializes the controller class.
     * @param url
     * @param rb
     */
    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }    

}

这是我的Login.fxml

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.text.*?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>

<AnchorPane id="AnchorPane" fx:id="lblMessage" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="com.LoginController">
   <children>
      <PasswordField fx:id="txtPassword" layoutX="200.0" layoutY="200.0" prefHeight="30.0" prefWidth="200.0" promptText="Password" />
      <TextField fx:id="txtUsername" layoutX="200.0" layoutY="140.0" prefHeight="30.0" prefWidth="200.0" promptText="Username" />
      <Button fx:id="btnLogin" layoutX="269.0" layoutY="251.0" mnemonicParsing="false" onAction="#btnLoginAction" prefHeight="30.0" text="Login">
         <font>
            <Font size="14.0" />
         </font></Button>
      <Label fx:id="lblMessage" layoutX="283.0" layoutY="71.0" text="Label" />
   </children>
</AnchorPane>

Here is my DateSelectionController.java

package com;

import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.Initializable;

/**
 * FXML Controller class
 *
 * @author Tyler
 */
public class DateSelectionController implements Initializable {

    /**
     * Initializes the controller class.
     */
    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
    }    

}

这是我的DateSelection.fxml

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.text.*?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>


<AnchorPane id="AnchorPane" prefHeight="400.0" prefWidth="600.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/8" fx:controller="com.DateSelectionController">
   <children>
      <Label layoutX="191.0" layoutY="164.0" text="Welcome">
         <font>
            <Font name="System Bold" size="50.0" />
         </font>
      </Label>
   </children>
</AnchorPane>

Answer 1

From Oracle:

The main() method is not required for JavaFX applications when the JAR file for the application is created with the JavaFX Packager tool, which embeds the JavaFX Launcher in the JAR file. However, it is useful to include the main() method so you can run JAR files that were created without the JavaFX Launcher, such as when using an IDE in which the JavaFX tools are not fully integrated. Also, Swing applications that embed JavaFX code require the main() method.

因此，一种解决方案是确保以完全支持 JavaFX 工具的方式构建它。另一种解决方案是添加一个 main 方法来启动应用程序。这样可以避免像这样的任何潜在问题，并且在不需要的情况下不会造成任何问题。

您的主要方法应如下所示：

public static void main(String[] args){
    Application.launch(Login.class, args);
}

这将简单地将控制权传递给 JavaFX 以正常处理。

javafx fxml程序错误（没有main方法）

javafx fxml program error(no main method)

java

netbeans

javafx

fxml