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我写一个包含ListView JavaFX应用程序。我尝试在初始化时填充列表视图并单击按钮会引发异常，并且由于我对javaFx的新手，我无法找到解决方案。请帮我找出原因，谢谢。填充的JavaFX的ListView抛出异常
FXML documnet
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.*?>
<?import java.lang.*?>
<?import java.util.*?>
<?import javafx.scene.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<BorderPane fx:id="root_borderPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="405.0" prefWidth="720.0" stylesheets="@styles/style.css" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="managefilesclientnetbeans.FXMLDocumentController">
<left>
<VBox BorderPane.alignment="CENTER">
<children>
<GridPane>
<columnConstraints>
<ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
<ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
</columnConstraints>
<rowConstraints>
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
</rowConstraints>
<children>
<Label fx:id="listLabel" text="Available files" GridPane.halignment="LEFT" />
<Button fx:id="refreshButton" alignment="CENTER_RIGHT" mnemonicParsing="false" onMouseClicked="#onRefreshButtonClicked" text="Button" GridPane.columnIndex="1" GridPane.halignment="RIGHT" />
</children>
<padding>
<Insets bottom="2.0" left="2.0" right="2.0" top="2.0" />
</padding>
</GridPane>
<ListView prefHeight="286.0" prefWidth="166.0" VBox.vgrow="ALWAYS" />
</children>
</VBox>
</left>
<center>
<GridPane>
<columnConstraints>
<ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" />
</columnConstraints>
<rowConstraints>
<RowConstraints minHeight="10.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
</rowConstraints>
<children>
<Pane fx:id="previewPane" prefHeight="200.0" prefWidth="200.0" BorderPane.alignment="CENTER" GridPane.vgrow="ALWAYS" />
<HBox fx:id="controlsPane" alignment="CENTER_LEFT" spacing="10.0" GridPane.rowIndex="1">
<children>
<Button fx:id="downloadButton" mnemonicParsing="false" text="Download" />
<Button fx:id="uploadButton" mnemonicParsing="false" text="Upload" />
</children>
<GridPane.margin>
<Insets bottom="5.0" left="5.0" right="5.0" top="5.0" />
</GridPane.margin>
</HBox>
</children>
</GridPane>
</center>
</BorderPane>
控制器类
package managefilesclientnetbeans;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.ListView;
import javafx.scene.control.Tooltip;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.Pane;
import managefilesclientnetbeans.sime.seven.ClientHandler;
public class FXMLDocumentController implements Initializable {
ClientHandler clientHandler = new ClientHandler();
ObservableList<String> content;
@FXML
public Label listLabel;
@FXML
public BorderPane root_borderPane;
@FXML
public Button refreshButton;
@FXML
public ListView<String> filesListView;
@FXML
public Button downloadButton;
@FXML
public Button uploadButton;
@FXML
public Pane previewPane;
@FXML
public Pane controlsPane;
@Override
public void initialize(URL url, ResourceBundle rb) {
assert root_borderPane != null : "fx:id=\"root_boarderPane\" was not "
+ "injected check the FXML file";
assert refreshButton != null : "refreshButton was not injected, check"
+ " your FXML file";
assert previewPane != null : "previewPane was not injected, check"
+ " your FXML file";
assert controlsPane != null : "controlsPane was not injected, check"
+ " your FXML file";
assert downloadButton != null : "downloadButton was not injected, check"
+ " your FXML file";
assert uploadButton != null : "uploadButton was not injected, check"
+ " your FXML file";
assert listLabel != null : "listLabel was not initialized, check "
+ "your FXML file";
content = FXCollections
.observableArrayList(clientHandler.getListOfFiles());
for(String str : content)
System.out.println(str);
filesListView.setItems(content); //this line here cases the error
//当注释掉应用程序启动，但点击按钮会导致//错误然后 断言filesListView = NULL！“filesListView未初始化，请检查“ +”您的FXML文件“; }
@FXML
public void onRefreshButtonClicked(MouseEvent event){
filesListView.setItems(content);
}
}
应用程序类
由于线路package managefilesclientnetbeans;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.stage.Stage;
public class ManageFilesClientNetBeans extends Application {
@Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("FXMLDocument.fxml"));
Scene scene = new Scene(root);
stage.setTitle("Remote Files Client");
stage.getIcons().add(new Image(ManageFilesClientNetBeans.class.getResourceAsStream("images/synced.png")));
stage.setScene(scene);
stage.show();
}
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
launch(args);
}
}
堆栈跟踪
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:483)
at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:363)
at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:303)
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:483)
at sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:875)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$147(LauncherImpl.java:157)
at com.sun.javafx.application.LauncherImpl$$Lambda$48/815033865.run(Unknown Source)
at java.lang.Thread.run(Thread.java:745)
Caused by: javafx.fxml.LoadException:
file:/D:/vamk/TutorialWS/RESTAPIsWS/manageFilesClientNetBeans/dist/run1793002454/manageFilesClientNetBeans.jar!/managefilesclientnetbeans/FXMLDocument.fxml
at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2595)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2573)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2435)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3208)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3169)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3142)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3118)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3098)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3091)
at managefilesclientnetbeans.ManageFilesClientNetBeans.start(ManageFilesClientNetBeans.java:23)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$153(LauncherImpl.java:821)
at com.sun.javafx.application.LauncherImpl$$Lambda$51/53700426.run(Unknown Source)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$166(PlatformImpl.java:323)
at com.sun.javafx.application.PlatformImpl$$Lambda$45/584634336.run(Unknown Source)
at com.sun.javafx.application.PlatformImpl.lambda$null$164(PlatformImpl.java:292)
at com.sun.javafx.application.PlatformImpl$$Lambda$47/1879407574.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$165(PlatformImpl.java:291)
at com.sun.javafx.application.PlatformImpl$$Lambda$46/501263526.run(Unknown Source)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$141(WinApplication.java:102)
at com.sun.glass.ui.win.WinApplication$$Lambda$37/96639997.run(Unknown Source)
... 1 more
Caused by: java.lang.NullPointerException
，这里是从按钮的堆栈跟踪点击
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1762)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1645)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$ClickGenerator.postProcess(Scene.java:3437)
at javafx.scene.Scene$ClickGenerator.access$7900(Scene.java:3365)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3733)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3452)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1728)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2461)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:348)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:273)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:382)
at com.sun.glass.ui.View.handleMouseEvent(View.java:553)
at com.sun.glass.ui.View.notifyMouse(View.java:925)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$141(WinApplication.java:102)
at com.sun.glass.ui.win.WinApplication$$Lambda$37/96639997.run(Unknown Source)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1757)
... 30 more
Caused by: java.lang.NullPointerException
at managefilesclientnetbeans.FXMLDocumentController.onRefreshButtonClicked(FXMLDocumentController.java:80)
... 40 more
谢谢这就是问题所在，并分配ID后，它的工作原理。 – Sime