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我刚开始使用 JavaFX，我正在尝试构建一个带有标签、文本字段和按钮的简单应用程序，单击该按钮时，会将标签的值设置为文本字段的值。一切顺利，直到我将控制器连接到主文件。这是我的代码：
主.java
package application;
import java.io.IOException;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.layout.AnchorPane;
public class Main extends Application {
private Stage primaryStage;
@Override
public void start(Stage primaryStage) {
this.primaryStage = primaryStage; // connect primary stage
mainWindow();
}
// main window
public void mainWindow() {
try {
// view
FXMLLoader loader = new FXMLLoader(Main.class.getResource("/MainWindowView.fxml"));
AnchorPane pane = loader.load();
// controller
MainWindowController mainWindowController = loader.getController();
mainWindowController.setMain(this);
// scene on stage
Scene scene = new Scene(pane);
primaryStage.setScene(scene);
primaryStage.show();
} catch (IOException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
launch(args);
}
}
主窗口视图.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.text.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.layout.AnchorPane?>
<AnchorPane prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.MainWindowController">
<children>
<Label fx:id="label" alignment="CENTER" layoutX="291.0" layoutY="164.0" text="Label" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0">
<font>
<Font size="20.0" />
</font>
</Label>
<HBox alignment="CENTER" layoutX="201.0" layoutY="208.0" spacing="20.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0">
<children>
<TextField fx:id="field" layoutX="201.0" layoutY="208.0" />
<Button layoutX="381.0" layoutY="208.0" mnemonicParsing="false" onAction="#handleButton" text="Change Text" />
</children>
</HBox>
</children>
</AnchorPane>
主窗口控制器.java
package application;
import javafx.fxml.FXML;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
public class MainWindowController {
// views
@FXML private Label label;
@FXML private TextField field;
private Main main;
// connect main class to controller
public void setMain(Main main) {
this.main = main;
}
// assign text field text to label on button click
public void handleButton() {
String text = field.getText();
label.setText(text);
field.clear();
}
}
我尝试了在 StackOverflow 上找到的多个答案，但我发现的所有答案都是 2 年前的，对我的代码没有任何积极影响。
编辑：堆栈跟踪在这里：
Exception in Application start method
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:497)
at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
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:497)
at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$155(LauncherImpl.java:182)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalStateException: Location is not set.
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2434)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
at application.Main.mainWindow(Main.java:27)
at application.Main.start(Main.java:19)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
Exception running application application.Main
原文由 Robert Valencia 发布，翻译遵循 CC BY-SA 4.0 许可协议
java
对于将来遇到完全相同问题的任何人，正如 James_D 和其他答案贡献者所提到的，删除路径开头的“/”可以解决问题，因此请使用
代替