JavaFX场景构建器下如何在Controller中实现按钮点击弹出新窗口

Hey there! I see you're trying to launch a popup window from your Controller instead of the Main class, and your current code isn't working because of misconfigured FXMLLoader settings. Let's fix this step by step.

The Problem with Your Current Code #

You’re setting loader.setRoot(this) and loader.setController(this), which tells the FXMLLoader to use your main controller as both the root node and controller for the popup. That’s not right—your popup should be a separate, independent UI component with its own structure.

Corrected Controller Code #

Here’s the proper way to load and display your Popup.fxml from the Controller:

import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.Node;
import javafx.stage.Stage;
import javafx.event.ActionEvent;
import java.io.IOException;

// ... rest of your Controller class code ...

@FXML
private void onButtonClicked(ActionEvent ae) {
    try {
        // Load the Popup.fxml file (double-check the path matches your project structure)
        FXMLLoader loader = new FXMLLoader(getClass().getResource("Popup.fxml"));
        Parent popupRoot = loader.load();
        
        // Create a new Stage for the popup window
        Stage popupStage = new Stage();
        popupStage.setTitle("My Popup"); // Set your preferred window title
        popupStage.setScene(new Scene(popupRoot));
        
        // Optional (but recommended): Attach the popup to the main window
        // This makes the popup stay on top of the main window and minimize alongside it
        popupStage.initOwner(((Node) ae.getSource()).getScene().getWindow());
        
        // Show the popup window
        popupStage.show();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

Key Details to Keep in Mind: #

• Remove setRoot and setController: Unless your popup intentionally shares the same controller as the main interface (which it shouldn’t), let FXMLLoader handle the controller automatically. If your popup needs its own logic, add a fx:controller attribute to Popup.fxml pointing to its dedicated controller class:

  <!-- Inside Popup.fxml -->
  <AnchorPane fx:controller="your.package.name.PopupController" ...>
      <!-- Your popup UI elements go here -->
  </AnchorPane>
  

• Path Validation: Make sure Popup.fxml is in the same package as your Controller class, or adjust the resource path to an absolute one (e.g., "/com/yourproject/Popup.fxml") if it’s in a different location.
• initOwner: This optional setting ties the popup to the main window, creating a more intuitive user experience by keeping the popup linked to its parent window.

That should get your popup working smoothly from the Controller class!

内容的提问来源于stack exchange，提问作者Jino