Question

我看了很多页面试图找出如何切换场景，但我没有成功。

我有一个计算器，我的目标是选择一个菜单选项来改变计算器（即：基本和科学）。现在我只是测试，所以这里是我的代码与此问题相关（我使用的是Scene Builder）：

@FXML private MenuItem basic;
@FXML private MenuItem testSwitch;


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

}
@Override
public void start(Stage primaryStage) throws Exception
{
   Parent pane = FXMLLoader.load(
           getClass().getResource( "calculator.fxml" ) );

   Scene scene = new Scene( pane );
   primaryStage.setScene(scene);
   primaryStage.setTitle( "Calculator" );
   primaryStage.show();

}
@FXML
public void handleMenuOption(ActionEvent e) 
{
    if(e.getSource()==basic)
    {
        changeScene("calculator.fxml");
    }
    else if(e.getSource()==testSwitch)
    {
        changeScene("TestSwitch.fxml");
    }
}
public void changeScene(String fxml) 
{
    //this prints out
    System.out.println(fxml);
}

修改我已经尝试了很多东西。无论如何，我总是得到这个NullPointerException。我觉得它可能与在场景构建器中设置某些内容有关，但我一直无法找到答案

Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(Unknown Source)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
at javafx.event.Event.fireEvent(Unknown Source)
at javafx.scene.control.MenuItem.fire(Unknown Source)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.doSelect(Unknown Source)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.lambda$createChildren$343(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
at javafx.event.Event.fireEvent(Unknown Source)
at javafx.scene.Scene$MouseHandler.process(Unknown Source)
at javafx.scene.Scene$MouseHandler.access$1500(Unknown Source)
at javafx.scene.Scene.impl_processMouseEvent(Unknown Source)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(Unknown Source)
at    com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.notifyMouse(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.reflect.misc.Trampoline.invoke(Unknown Source)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.reflect.misc.MethodUtil.invoke(Unknown Source)
... 44 more
Caused by: java.lang.NullPointerException
at CalculatorMain.changeScene(CalculatorMain.java:75)
at CalculatorMain.handleMenuOption(CalculatorMain.java:64)
... 53 more




at CalculatorMain.changeScene(CalculatorMain.java:75)
This is at:stage . getScene() . setRoot(pane);


at CalculatorMain.handleMenuOption(CalculatorMain.java:64)
This is at:changeScene ("TestSwitch.fxml");

工作代码：

我使用下面的建议并使用此代码使其正常工作：

private Stage stage;

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

@Override
public void start(Stage primaryStage) throws Exception
{
    this.stage = primaryStage;
    FXMLLoader loader = new FXMLLoader(getClass()
            .getResource("calculator.fxml"));
    Parent root = (Parent)loader.load();
    BasicCalculatorView controller = (BasicCalculatorView)loader.getController();
    controller.setModel(new BasicCalculatorModelTest(controller));
    controller.setLogic(this);
    primaryStage.setTitle("Calculator");
    primaryStage.setScene(new Scene(root));
    primaryStage.show();
}

public void switchScene(String fxmlFile)
{

    FXMLLoader loader = new FXMLLoader(getClass()
            .getResource(fxmlFile));
    Parent root;
    try 
    {
        root = (Parent)loader.load();
        if(fxmlFile.equals("calculator.fxml"))
        {
            BasicCalculatorView controller = (BasicCalculatorView)loader.getController();
            controller.setModel(new BasicCalculatorModelTest(controller));
            controller.setLogic(this);
        }
        else if(fxmlFile.equals("TestSwitch.fxml"))
        {
            TestSwitch controller = (TestSwitch)loader.getController();
            controller.setLogic(this);
        }
        this.stage.setScene(new Scene(root));
    } 
    catch (IOException e)
    {
        e.printStackTrace();
    }

}

Answer 1

我写了这个控制器来跟踪不同的场景图。

public class ScreenController {
    private HashMap<String, Pane> screenMap = new HashMap<>();
    private Scene main;

    public ScreenController(Scene main) {
        this.main = main;
    }

    protected void addScreen(String name, Pane pane){
         screenMap.put(name, pane);
    }

    protected void removeScreen(String name){
        screenMap.remove(name);
    }

    protected void activate(String name){
        main.setRoot( screenMap.get(name) );
    }
}

所以我可以写：

ScreenController screenController = new ScreenController(scene);
screenController.add("calculator", FXMLLoader.load(getClass().getResource( "calculator.fxml" )));
screenController.add("testSwitch", FXMLLoader.load(getClass().getResource( "TestSwitch.fxml" )));
screenController.activate("calculator");

这是全屏应用程序的解决方法，每次舞台切换场景时都会显示MacOS全屏转换。

Answer 2

不是切换Scenes，而是在已存在的Scene

上切换根节点

Answer 3

如果你想改变场景你会这样做（注意舞台是应用程序的成员）：

private Stage primaryStage;

@Override
public void start(Stage primaryStage) throws Exception {
    this.primaryStage = primaryStage;
    ...
}

public void changeScene(String fxml){
    Parent pane = FXMLLoader.load(
           getClass().getResource(fxml));

   Scene scene = new Scene( pane );
   primaryStage.setScene(scene);
}

然而正如@Eugene_Ryzhikov已经指出的那样，只更改现有场景的根内容是一个更好的解决方案：

public void changeScene(String fxml){
    Parent pane = FXMLLoader.load(
           getClass().getResource(fxml));

   primaryStage.getScene().setRoot(pane);
}

Answer 4

似乎OP已经解决了它，但由于它仍然是开放的和未解决的，我将分享我在另一个答案中找到的解决方案。记住要么在问题解决后选择正确的答案或发布自己的解决方案，它会帮助未来的人们在同一个问题上运行（就像我一样）。

我只是在同一个问题上运行，this answer在短暂而干净的情况下完美地解决了我的问题。

@FXML
private void handleButtonAction(ActionEvent event) {
System.out.println("You clicked me!");
label.setText("Hello World!");
//Here I want to swap the screen!

Stage stageTheEventSourceNodeBelongs = (Stage) ((Node)event.getSource()).getScene().getWindow();
// OR
Stage stageTheLabelBelongs = (Stage) label.getScene().getWindow();
// these two of them return the same stage
// Swap screen
stage.setScene(new Scene(new Pane()));

}

PS：请记得查看原始答案并进行投票。这家伙值得...

PPS。：我不确定只是复制一个答案是可以的（而不是仅通过评论分享链接），但由于这个答案没有正确答案，我决定这样做是为了提高知名度。

Answer 5

TypesController.java
package todoapp;
import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;
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.CheckBox;
import javafx.stage.Stage;

public class TypesController implements Initializable {
@FXML
private CheckBox c1;
@FXML
private CheckBox c2;
public void clicked(ActionEvent e) throws IOException {
Parent home_page_parent =FXMLLoader.load(getClass().getResource("AddDcuFXML.fxml"));
Scene home_page_scene = new Scene(home_page_parent);
Stage app_stage = (Stage) ((Node) e.getSource()).getScene().getWindow();
app_stage.hide(); //optional
app_stage.setScene(home_page_scene);
app_stage.show();
}
public void clicked1(ActionEvent e) throws IOException {
Parent home_page_parent =   FXMLLoader.load(getClass().getResource("AddDcuFXML.fxml"));
    Scene home_page_scene = new Scene(home_page_parent);
    Stage app_stage = (Stage) ((Node)e.getSource()).getScene().getWindow();
   app_stage.hide(); //optional
   app_stage.setScene(home_page_scene);
   app_stage.show();
   }
  @Override
  public void initialize(URL arg0, ResourceBundle arg1) {
 // TODO Auto-generated method stub
  } }

Answer 6

我编写了一个库，使切换场景变得非常简单。您只需为每个 Integer 类型的场景选择一个唯一 ID，然后使用一行代码添加场景。当您需要显示场景时，您可以从项目中的任何类调用该方法并将场景的 ID 传递给它。

You can find the library here 以及 Maven 导入 xml。

Answer 7

<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.image.*?>
 <?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="491.0" prefWidth="386.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="todoapp.TypesController">
<children>
  <CheckBox fx:id="c1" layoutX="55.0" layoutY="125.0" mnemonicParsing="false" onAction="#clicked" text="ADD dcu" />
  <CheckBox fx:id="c2" layoutX="55.0" layoutY="177.0" mnemonicParsing="false" onAction="#clicked1" text="Display dcu" />
  <Label layoutX="31.0" layoutY="58.0" prefHeight="37.0" prefWidth="276.0" text="Choose any one of the options" textFill="#1b29cd">
     <font>
        <Font name="Arial Bold" size="18.0" />
     </font>
  </Label>
</children>

如何在JavaFX中切换场景

7 个答案: