JavaFX FXML应用程序不会运行
JavaFX FXML应用程序不会运行
提问于 2018-10-14 05:04:32
我正在尝试遵循教程here。但是，我的IDE Eclipse似乎不想使用它。我尝试将代码示例复制并粘贴到我的IDE中，但同样的错误弹出。遗憾的是，没有显示任何窗口。
请帮我找出这段代码出了什么问题。
错误：
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:498)
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:498)
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$154(LauncherImpl.java:182)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException: Location is required.
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3207)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
at application.RegistrationFormApplication.start(RegistrationFormApplication.java:13)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at com.sun.glass.ui.gtk.GtkApplication.lambda$null$48(GtkApplication.java:139)
... 1 more
Exception running application application.RegistrationFormApplication主类：
package application;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class RegistrationFormApplication extends Application {
@Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("registration_form.fxml"));
primaryStage.setTitle("Registration Form FXML Application");
primaryStage.setScene(new Scene(root, 800, 500));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}FXML文档：
<?import javafx.scene.layout.GridPane?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.text.Font?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.control.PasswordField?>
<?import javafx.scene.control.Button?>
<GridPane fx:controller="javafx.example.RegistrationFormController"
xmlns:fx="http://javafx.com/fxml" alignment="center"
hgap="10" vgap="10">
<padding><Insets top="40" right="40" bottom="40" left="40"/></padding>
<columnConstraints>
<ColumnConstraints minWidth="100" prefWidth="100"
maxWidth="Infinity" halignment="RIGHT">
</ColumnConstraints>
<ColumnConstraints minWidth="200" prefWidth="200"
maxWidth="Infinity" hgrow="ALWAYS">
</ColumnConstraints>
</columnConstraints>
<!-- Add Header Label -->
<Label text="Registration Form (FXML)" GridPane.columnIndex="0"
GridPane.rowIndex="0" GridPane.columnSpan="2"
GridPane.rowSpan="1" GridPane.halignment="CENTER" >
<font>
<Font name="Arial" size="24" ></Font>
</font>
<GridPane.margin>
<Insets top="20" right="0" bottom="20" left="0"></Insets>
</GridPane.margin>
</Label>
<!-- Add Name Label -->
<Label text="Full Name : " GridPane.columnIndex="0"
GridPane.rowIndex="1" >
</Label>
<!-- Add Name Text Field -->
<TextField fx:id="nameField" prefHeight="40"
GridPane.columnIndex="1" GridPane.rowIndex="1"/>
<!-- Add Email Label -->
<Label text="Email ID : " GridPane.columnIndex="0"
GridPane.rowIndex="2" >
</Label>
<!-- Add Email Text Field -->
<TextField fx:id="emailField" prefHeight="40"
GridPane.columnIndex="1" GridPane.rowIndex="2"/>
<!-- Add Password Label -->
<Label text="Password : " GridPane.columnIndex="0"
GridPane.rowIndex="3" >
</Label>
<!-- Add Password Field -->
<PasswordField fx:id="passwordField" prefHeight="40"
GridPane.columnIndex="1" GridPane.rowIndex="3"/>
<!-- Add Submit Button -->
<Button fx:id="submitButton" text="Submit"
prefWidth="100" prefHeight="40" defaultButton="true"
GridPane.columnIndex="0" GridPane.rowIndex="4"
GridPane.columnSpan="2" GridPane.rowSpan="1"
GridPane.halignment="CENTER"
onAction="#handleSubmitButtonAction">
<GridPane.margin>
<Insets top="20" right="0" bottom="20" left="0"></Insets>
</GridPane.margin>
</Button>
</GridPane>使用FXML文档的类：
package application;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Alert;
import javafx.scene.control.Button;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.stage.Window;
public class RegistrationFormController {
@FXML
private TextField nameField;
@FXML
private TextField emailField;
@FXML
private PasswordField passwordField;
@FXML
private Button submitButton;
@FXML
protected void handleSubmitButtonAction(ActionEvent event) {
Window owner = submitButton.getScene().getWindow();
if(nameField.getText().isEmpty()) {
AlertHelper.showAlert(Alert.AlertType.ERROR, owner, "Form Error!",
"Please enter your name");
return;
}
if(emailField.getText().isEmpty()) {
AlertHelper.showAlert(Alert.AlertType.ERROR, owner, "Form Error!",
"Please enter your email id");
return;
}
if(passwordField.getText().isEmpty()) {
AlertHelper.showAlert(Alert.AlertType.ERROR, owner, "Form Error!",
"Please enter a password");
return;
}
AlertHelper.showAlert(Alert.AlertType.CONFIRMATION, owner, "Registration Successful!",
"Welcome " + nameField.getText());
}
}AlertHelper类(在上面的类中调用)：
package application;
import javafx.scene.control.Alert;
import javafx.stage.Window;
public class AlertHelper {
public static void showAlert(Alert.AlertType alertType, Window owner, String title, String message) {
Alert alert = new Alert(alertType);
alert.setTitle(title);
alert.setHeaderText(null);
alert.setContentText(message);
alert.initOwner(owner);
alert.show();
}
}回答 1
Stack Overflow用户
回答已采纳
发布于 2018-10-15 07:44:26
我有两个问题导致程序无法正确显示。
首先，这句话
Parent root = FXMLLoader.load(getClass().getResource("registration_form.fxml"));
应该是的，
Parent root = FXMLLoader.load(getClass().getResource("/registration_form.fxml"));
另外，我的图形驱动程序也过时了。
因为我的操作系统是Ubuntu 18.04，所以更新它们的过程如下。
首先，我打开程序"Ubuntu Software"，点击屏幕右上角的"Software & Updates“，然后在弹出的窗口中点击"Additional Drivers”选项卡。
然后，我选择"NVIDIA driver metapackage from nvidia-driver-410“并点击"Apply Changes”。
这解决了我的问题，并允许程序正常显示。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/52797309
复制相关文章
相似问题