使用FXML的JavaFX登录

Question

I did a simple login window with Eclipse (Main.java, application.css, Login.fxml) How can I add a listener on the 2 buttons?

Main.java

package application;

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

public class Main extends Application {
    @Override
    public void start(Stage primaryStage) {
        try {
            Parent root = FXMLLoader.load(getClass().getResource("Login.fxml"));
            Scene scene = new Scene(root,350,150);
            scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
            primaryStage.setScene(scene);
            primaryStage.setTitle("LOGIN");
            primaryStage.show();
        } catch(Exception e) {
            e.printStackTrace();
        }
    }

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

Login.fxml

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

<?import javafx.scene.layout.GridPane?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.geometry.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.text.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.control.PasswordField?>
<?import javafx.scene.layout.HBox?>

<GridPane xmlns:fx="http://javafx.com/fxml/1" hgap="10" vgap="10">
    <padding>
        <Insets top="10" right="10" bottom="10" left="10"/>
    </padding>
    <children>
        <Label  text="Username:" GridPane.columnIndex="0"
                GridPane.rowIndex="0" GridPane.halignment="RIGHT" />
        <Label  text="Password:" GridPane.columnIndex="0"
                GridPane.rowIndex="1" GridPane.halignment="RIGHT" />
        <TextField GridPane.columnIndex="1" GridPane.rowIndex="0"/>
        <PasswordField GridPane.columnIndex="1" GridPane.rowIndex="1" />
        <HBox GridPane.columnIndex="0" GridPane.rowIndex="2"
              GridPane.columnSpan="2" alignment="CENTER" spacing="10">
            <children>
                <Button text="Login" />
                <Button text="Annulla" />
            </children>   
        </HBox>
    </children>
</GridPane>

application.css

/* JavaFX CSS - Leave this comment until you have at least create one rule which uses -fx-Property */
.label {
    -fx-text-fill: rgb(255,0,0);
    -fx-font-weight: bold;
    -fx-font-style: italic;
}

I need to get username e password and connect to a database

Answer 1

You need to define a controller class .

You can inject the controls into the controller instance by annotating them @FXML , and you can associate methods in the controller with handlers for the buttons:

package application ;

public class LoginController {

    @FXML
    private TextField userIdField ;

    @FXML
    private PasswordField passwordField ;

    @FXML
    private void login() {
        String userId = userIdField.getText();
        String password = passwordField.getText();

        // etc...
    }
}

In your FXML, use fx:controller on the root element to specify the class to be used to create a controller. Use fx:id to inject an element into the controller, and use onAction="#methodName" to specify a handler method for the action on a button:

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

<?import javafx.scene.layout.GridPane?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.geometry.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.text.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.control.PasswordField?>
<?import javafx.scene.layout.HBox?>

<GridPane xmlns:fx="http://javafx.com/fxml/1" hgap="10" vgap="10" 
    fx:controller="application.LoginController">

    <padding>
        <Insets top="10" right="10" bottom="10" left="10"/>
    </padding>
    <children>
        <Label  text="Username:" GridPane.columnIndex="0"
                GridPane.rowIndex="0" GridPane.halignment="RIGHT" />
        <Label  text="Password:" GridPane.columnIndex="0"
                GridPane.rowIndex="1" GridPane.halignment="RIGHT" />
        <TextField fx:id="userIdField" GridPane.columnIndex="1" GridPane.rowIndex="0"/>
        <PasswordField fx:id="passwordField" GridPane.columnIndex="1" GridPane.rowIndex="1" />
        <HBox GridPane.columnIndex="0" GridPane.rowIndex="2"
              GridPane.columnSpan="2" alignment="CENTER" spacing="10">
            <children>
                <Button text="Login" onAction="#login" />
                <Button text="Annulla" />
            </children>   
        </HBox>
    </children>
</GridPane>