如何解决JavaFX Controller-如何获得他
我在联系Controller时遇到问题。 我有一个包含两个部分的主模板:菜单和主要内容 在两个单独的FXML文件中,我具有菜单(MenuTemplate.fxml)和主要内容(Content1Template.fxml)。 菜单和主要内容的加载正确进行
当主要内容想要在按下按钮后更改文本时,出现问题。 Content1Utils.java必须在Content1Controller.java中设置文本。 我想我得去控制器了。我只是有一个问题怎么做。
Luncher.java
package sample;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
import sample.main.MainController;
import java.io.File;
import java.net.URL;
public class Launcher extends Application {
private static MainController mainController;
@Override
public void start(Stage primaryStage) throws Exception{
URL mainTemplate = new File("src/sample/main/MainTemplate.fxml").toURI().toURL();
FXMLLoader loader = new FXMLLoader();
loader.setLocation(mainTemplate);
Parent root = loader.load();
mainController = loader.getController();
Scene scene = new Scene(root);
primaryStage.setTitle("Hello World");
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
public MainController getMainController(){
return mainController;
}
}
MainController.java
package sample.main;
import com.jfoenix.controls.JFXDrawer;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.layout.VBox;
import java.io.File;
import java.io.IOException;
import java.net.URL;
public class MainController {
@FXML private VBox rootBox;
@FXML private JFXDrawer menuBox;
@FXML private VBox contentBox;
@FXML
void initialize() throws IOException {
URL menuTemplate = new File("src/sample/menu/MenuTemplate.fxml").toURI().toURL();
VBox contentMenu = FXMLLoader.load(menuTemplate);
menuBox.setContent(contentMenu);
}
public void changeContentBox(VBox content){
contentBox.getChildren().setAll(content);
}
}
MenuController.java
package sample.menu;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.control.Button;
import javafx.scene.layout.VBox;
import sample.Launcher;
import sample.main.MainController;
import java.io.File;
import java.io.IOException;
import java.net.URL;
public class MenuController {
@FXML private VBox menuRoot;
@FXML private Button menuButton1;
@FXML private Button menuButton2;
@FXML private Button menuButton3;
private MainController mainController;
@FXML
void initialize(){
}
public void clickButton1() throws IOException {
URL content1Template = new File("src/sample/content1/Content1Template.fxml").toURI().toURL();
VBox contentContent1 = FXMLLoader.load(content1Template);
mainController = new Launcher().getMainController();
mainController.changeContentBox(contentContent1);
}
}
Content1Controller.java
package sample.content1;
import javafx.fxml.FXML;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;
import javafx.scene.layout.VBox;
public class Content1Controller {
@FXML private VBox content1root;
@FXML private Button content1Button;
@FXML private TextArea content1TextArea;
@FXML
void initialize(){
}
public void content1Button(){
Content1Utils contentUtils = new Content1Utils();
contentUtils.prepareText("XXX");
}
public void setTextInArea(String txt){
content1TextArea.setText(txt);
}
}
Content1Utils.java
package sample.content1;
public class Content1Utils {
public void prepareText(String txt){
String newTxt = txt + " - Test123";
new Content1Controller().setTextInArea(newTxt);
}
}
MainTemplate.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import com.jfoenix.controls.JFXDrawer?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.layout.VBox?>
<VBox fx:id="rootBox" prefheight="442.0" prefWidth="665.0" xmlns="http://javafx.com/javafx/8.0.171" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.main.MainController">
<children>
<HBox maxHeight="1.7976931348623157E308" maxWidth="1.7976931348623157E308" VBox.vgrow="ALWAYS">
<children>
<JFXDrawer fx:id="menuBox" style="-fx-background-color: #ebd534;" />
<VBox fx:id="contentBox" maxHeight="1.7976931348623157E308" maxWidth="1.7976931348623157E308" style="-fx-background-color: #34b7eb;" HBox.hgrow="ALWAYS" />
</children>
</HBox>
</children>
</VBox>
MenuTemplate.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.layout.VBox?>
<VBox fx:id="menuRoot" prefheight="442.0" prefWidth="100.0" xmlns="http://javafx.com/javafx/8.0.171" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.menu.MenuController">
<children>
<Button fx:id="menuButton1" maxHeight="100.0" maxWidth="1.7976931348623157E308" mnemonicParsing="false" onAction="#clickButton1" text="Button 1" VBox.vgrow="ALWAYS" />
<Button fx:id="menuButton2" maxHeight="100.0" maxWidth="1.7976931348623157E308" mnemonicParsing="false" text="Button 2" VBox.vgrow="ALWAYS" />
<Button fx:id="menuButton3" maxHeight="100.0" maxWidth="1.7976931348623157E308" mnemonicParsing="false" text="Button3" VBox.vgrow="ALWAYS" />
</children>
</VBox>
Content1Template.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.TextArea?>
<?import javafx.scene.layout.VBox?>
<VBox fx:id="content1root" alignment="CENTER" prefheight="442.0" prefWidth="565.0" xmlns="http://javafx.com/javafx/8.0.171" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.content1.Content1Controller">
<children>
<Button fx:id="content1Button" contentdisplay="CENTER" mnemonicParsing="false" onAction="#content1Button" prefheight="48.0" prefWidth="400.0" text="Button" textAlignment="CENTER">
<VBox.margin>
<Insets />
</VBox.margin>
</Button>
<TextArea fx:id="content1TextArea" maxWidth="400.0" prefheight="200.0" prefWidth="400.0">
<VBox.margin>
<Insets top="10.0" />
</VBox.margin>
</TextArea>
</children>
</VBox>
错误
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1774)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventdispatcher.dispatchBubblingEvent(CompositeEventdispatcher.java:59)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:394)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$353(GlassViewEventHandler.java:432)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:431)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(UnkNown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771)
... 48 more
Caused by: java.lang.NullPointerException
at sample.content1.Content1Controller.setTextInArea(Content1Controller.java:25)
at sample.content1.Content1Utils.prepareText(Content1Utils.java:8)
at sample.content1.Content1Controller.content1Button(Content1Controller.java:21)
... 58 more
解决方法
问题在这里:
public class Content1Utils {
public void prepareText(String txt){
String newTxt = txt + " - Test123";
new Content1Controller().setTextInArea(newTxt);
}
}
您正在创建一个未从FXML初始化的新控制器实例,因此它没有有效的TextArea字段。您不想让您的实用程序类以这种方式工作。
尝试:
public void content1Button(){
Content1Utils contentUtils = new Content1Utils(this);
contentUtils.prepareText("XXX");
}
Content1Utils.java:
package sample.content1;
public class Content1Utils {
private final Content1Controller controller;
public Content1utils(Content1Controller ctrl) {
this.controller = ctrl;
}
public void prepareText(String txt){
String newTxt = txt + " - Test123";
controller.setTextInArea(newTxt);
}
}
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