JavaFX : Pass parameters while instantiating controller class
As a p has pointed out in the comments you can use a controller factory, and it's easier with a lambda function:
String data = "hsusanoo";
FXMLLoader loader = new FXMLLoader(getClass().getResource("/fxml/WorkOrder.fxml"));
loader.setControllerFactory(controllerClass -> new WorkOrderController(data));
Parent root = loader.load();
The two easiest ways of doing it for small applications are :
Do not specify the
fx:controller
in the fxml. Create a controller instance by passing data to it and then pass it to the FXMLLoader.Specify the
fx:controller
in the fxml. Fetch the controller instance from the FXMLLoader and pass the data to the controller.
The following are the examples for both the above said types. Each of the example have 3 components :
- FXML - The FXML file, which
doesn't have
thefx:controller
declaration for the first type and has it for the second type. - Controller - Has a
constructor
for the first type. Hassetter methods
for the second type. - Main - Used for loading FXML and pass data to the controller. For first case, it
sets the controller to FXMLLoader
. While in second, itfetches the controller from the FXMLLoader
.
1. Create a controller instance manually
FXML - Do not specify the fx:controller
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.FlowPane?>
<?import javafx.scene.control.Label?>
<FlowPane fx:id="root" xmlns:fx="http://javafx.com/fxml">
<children>
<Label fx:id="firstName" text="" />
<Label fx:id="lastName" text="" />
</children>
</FlowPane>
Controller - create a Constructor to accept default values
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
import java.net.URL;
import java.util.ResourceBundle;
public class SampleController implements Initializable {
private StringProperty firstNameString = new SimpleStringProperty();
private StringProperty lastNameString = new SimpleStringProperty();
/**
* Accepts the firstName, lastName and stores them to specific instance variables
*
* @param firstName
* @param lastName
*/
public SampleController(String firstName, String lastName) {
firstNameString.set(firstName);
lastNameString.set(lastName);
}
@FXML
Label firstName;
@FXML
Label lastName;
@Override
public void initialize(URL location, ResourceBundle resources) {
firstName.setText(firstNameString.get());
lastName.setText(lastNameString.get());
}
}
Main - Create a Controller instance, by passing value into it and then pass it to the FXMLLoader
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.layout.FlowPane;
import javafx.stage.Stage;
public class Main extends Application {
@Override
public void start(Stage primaryStage) throws Exception {
FXMLLoader loader = new FXMLLoader(getClass().getResource("Sample.fxml"));
// Create a controller instance
SampleController controller = new SampleController("itachi", "uchiha");
// Set it in the FXMLLoader
loader.setController(controller);
FlowPane flowPane = loader.load();
Scene scene = new Scene(flowPane, 200, 200);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
2. Fetch a controller instance from FXMLLoader
FXML - Has specified the fx:controller
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.FlowPane?>
<?import javafx.scene.control.Label?>
<!-- Controller Specified -->
<FlowPane fx:id="root" xmlns:fx="http://javafx.com/fxml" fx:controller="SampleController">
<children>
<Label fx:id="firstName" text="" />
<Label fx:id="lastName" text="" />
</children>
</FlowPane>
Controller - Has Setter methods to accept input
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
import java.net.URL;
import java.util.ResourceBundle;
public class SampleController implements Initializable {
@FXML
Label firstName;
@FXML
Label lastName;
@Override
public void initialize(URL location, ResourceBundle resources) {
}
/**
* Accepts a String and sets it to the firstName Label
*
* @param firstNameString
*/
public void setFirstName(String firstNameString) {
firstName.setText(firstNameString);
}
/**
* Accepts a String and sets it to the lastName Label
*
* @param lastNameString
*/
public void setLastName(String lastNameString) {
lastName.setText(lastNameString);
}
}
Main - Fetches the Controller instance from FXMLLoader after calling the load()
and then calls the setter methods to pass data.
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Scene;
import javafx.scene.layout.FlowPane;
import javafx.stage.Stage;
public class Main extends Application {
@Override
public void start(Stage primaryStage) throws Exception {
FXMLLoader loader = new FXMLLoader(getClass().getResource("Sample.fxml"));
FlowPane flowPane = loader.load();
// Get the Controller from the FXMLLoader
SampleController controller = loader.getController();
// Set data in the controller
controller.setFirstName("itachi");
controller.setLastName("uchiha");
Scene scene = new Scene(flowPane, 200, 200);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}