如何在场景图的节点中收听WindowEvent.WINDOW_SHOWN? [英] How to listen for WindowEvent.WINDOW_SHOWN in the nodes of the scene graph?
问题描述
似乎WindowEvent.WINDOW_SHOWN从来没有在场景图中的任何节点上调度,也没有(我可以找到)知道节点何时可见/渲染/显示。例如:
It seems WindowEvent.WINDOW_SHOWN never gets dispatched on any of the nodes in the scene graph, nor is there anyway (that I could find) to know when a node is visible/rendered/shown. For example:
TestLauncher.java
package com.example.javafx.event;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class TestLauncher extends Application
{
public static void main(String[] args)
{
Application.launch(TestLauncher.class, args);
}
@Override
public void start(Stage stage) throws Exception
{
Parent root = FXMLLoader.load(TestController.class.getResource("TestView.fxml"));
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
}
TestController.java / p>
TestController.java
package com.example.javafx.event;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.EventHandler;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.Parent;
import javafx.scene.control.TextField;
import javafx.stage.WindowEvent;
public class TestController implements Initializable
{
@FXML private Parent root;
@FXML private TextField serverAddressInput;
@FXML private TextField usernameInput;
@Override
public void initialize(URL url, ResourceBundle rb)
{
serverAddressInput.setText("127.0.0.1");
//won't work because stage isn't visible yet
trySetFocusOnUsernameInput1();
//apparently Stage never passes on any WindowEvents to the children...
trySetFocusOnUsernameInput2();
}
private void trySetFocusOnUsernameInput1()
{
usernameInput.requestFocus();
}
private void trySetFocusOnUsernameInput2()
{
root.addEventFilter(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>()
{
@Override
public void handle(WindowEvent window)
{
usernameInput.requestFocus();
}
});
root.addEventHandler(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>()
{
@Override
public void handle(WindowEvent window)
{
usernameInput.requestFocus();
}
});
}
public void handleWindowShownEvent()
{
usernameInput.requestFocus();
}
}
TestView.fxml / p>
TestView.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import java.lang.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<VBox
xmlns:fx="http://javafx.com/fxml"
fx:id="root"
fx:controller="com.example.javafx.event.TestController"
prefHeight="150"
prefWidth="200"
>
<children>
<TextField fx:id="serverAddressInput" />
<TextField fx:id="usernameInput" />
</children>
</VBox>
实际上,一个节点如何知道它是可见/渲染/显示的事实
So, actually, how else can a node become aware of the fact that it's visible/rendered/shown?
推荐答案
我想可能的解决方案之一是将以下方法添加到TestController.java
I guess one of the possible solutions is to add the following method to TestController.java
public void handleWindowShownEvent()
{
usernameInput.requestFocus();
}
然后更改开始
方法在 TestLauncher 到以下内容:
and then change the start
method in TestLauncher to the following:
@Override
public void start(Stage stage) throws Exception
{
FXMLLoader loader = new FXMLLoader();
Parent root = (Parent)loader.load(TestController.class.getResourceAsStream("TestView.fxml"));
final TestController controller = (TestController)loader.getController();
stage.addEventHandler(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>()
{
@Override
public void handle(WindowEvent window)
{
controller.handleWindowShownEvent();
}
});
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
我真的很欢迎其他解决方案,因为这个似乎太笨重...
I would really welcome other solutions as this one seems too clunky...
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