我已经为我的学者创建了这个小项目，它正在开发并且可以正常工作，直到我在其中添加了文本字段。我是JavaFx的新手，所以我在从youtube学习时创建了它。...将不胜感激。
1.Main.java
package sample;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class Main extends Application {
@Override
public void start(Stage primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
primaryStage.setTitle("Hello World");
primaryStage.setScene(new Scene(root, 300, 275));
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
2.Controller.java
package sample;
import java.io.*;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.scene.control.MenuBar;
import javafx.scene.control.MenuItem;
import javafx.scene.control.TextArea;
import javafx.stage.FileChooser;
import javax.xml.soap.Text;
import java.util.logging.Level;
import java.util.logging.Logger;
public class Controller{
FileChooser fileChooser = new FileChooser();
@FXML
private ResourceBundle resources;
@FXML
private URL location;
@FXML
private TextArea TextArea;
@FXML
private MenuBar MenuBar;
@FXML
private MenuItem createFile;
@FXML
private Text Text;
@FXML
void editSaveAs()
{
Text.setValue("helo w");
/* FileChooser.ExtensionFilter extFilter =
new FileChooser.ExtensionFilter("TXT files (*.txt)", "*.txt");
fileChooser.getExtensionFilters().add(extFilter);
File selectedFile = fileChooser.showSaveDialog(null);
if(selectedFile != null){
SaveFile(TextArea.getText(), selectedFile);
}*/
}
@FXML
void editOpen()
{
File selectedFile = fileChooser.showOpenDialog(null);
if (selectedFile!=null)
{
System.out.println(selectedFile.getPath());
try{
FileReader fileReader = new FileReader(selectedFile);
BufferedReader bufferedReader = new BufferedReader(fileReader);
String s ;
String f="" ;
while((s=bufferedReader.readLine())!=null)
{
f=f+s+"\n";
}
TextArea.setText(f);
bufferedReader.close();
}catch(Exception error)
{
System.out.println(error);
}
}
}
private void SaveFile(String content, File file){
try {
FileWriter fileWriter;
fileWriter = new FileWriter(file);
fileWriter.write(content);
fileWriter.close();
} catch (IOException ex) {
Logger.getLogger(Main.class
.getName()).log(Level.SEVERE, null, ex);
}
}
@FXML
void initialize() {
assert Text != null : "fx:id=\"text\" was not injected: check your FXML file 'sample.fxml'.";
assert TextArea != null : "fx:id=\"TextArea\" was not injected: check your FXML file 'textEditor.fxml'.";
assert MenuBar != null : "fx:id=\"MenuBar\" was not injected: check your FXML file 'textEditor.fxml'.";
}
}
3.sample.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Menu?>
<?import javafx.scene.control.MenuBar?>
<?import javafx.scene.control.MenuItem?>
<?import javafx.scene.control.ScrollBar?>
<?import javafx.scene.control.TextArea?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.text.Text?>
<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="499.0" prefWidth="500.0" xmlns="http://javafx.com/javafx/8.0.121" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
<children>
<MenuBar fx:id="MenuBar" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
<menus>
<Menu mnemonicParsing="false" text="File">
<items>
<MenuItem mnemonicParsing="false" text="New (Ctrl+N)" />
<MenuItem mnemonicParsing="false" onAction="#editOpen" text="Open (Ctrl+O)" />
<MenuItem mnemonicParsing="false" text="Save (Ctrl+N)" />
<MenuItem mnemonicParsing="false" onAction="#editSaveAs" text="Save As... " />
<MenuItem mnemonicParsing="false" text="Exit" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Edit">
<items>
<MenuItem mnemonicParsing="false" text="Undo (Ctrl+Z)" />
<MenuItem mnemonicParsing="false" text="Cut (Ctrl+X)" />
<MenuItem mnemonicParsing="false" text="Copy (Ctrl+C)" />
<MenuItem mnemonicParsing="false" text="Paste (Ctrl+V)" />
<MenuItem mnemonicParsing="false" text="Delete (Del)" />
<MenuItem mnemonicParsing="false" text="Find... (Ctrl+F)" />
<MenuItem mnemonicParsing="false" text="Replace... (Ctrl+H)" />
<MenuItem mnemonicParsing="false" text="Select All (Ctrl+A)" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Help">
<items>
<MenuItem mnemonicParsing="false" text="About" />
</items>
</Menu>
<Menu mnemonicParsing="false" text="Font Size">
<items>
<MenuItem mnemonicParsing="false" text="Unspecified Action">
<graphic>
<ScrollBar orientation="VERTICAL" />
</graphic>
</MenuItem>
</items>
</Menu>
</menus>
</MenuBar>
<TextArea fx:id="TextArea" layoutY="25.0" prefHeight="474.0" prefWidth="500.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="51.0" />
<Text id="Text" layoutY="48.0" text="sd" wrappingWidth="99.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" />
</children>
</AnchorPane>
这都是我来自ide的文件。...
，在其中添加文本后，我遇到了错误。
/usr/lib/jvm/java-8-oracle/bin/java -javaagent:/home/shubham/Downloads/idea-IU-181.5281.24/lib/idea_rt.jar=37607:/home/shubham/Downloads/idea-IU-181.5281.24/bin -Dfile.encoding=UTF-8 -classpath /usr/lib/jvm/java-8-oracle/jre/lib/charsets.jar:/usr/lib/jvm/java-8-oracle/jre/lib/deploy.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/cldrdata.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/dnsns.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/jaccess.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/jfxrt.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/localedata.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/nashorn.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/sunec.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/sunjce_provider.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/sunpkcs11.jar:/usr/lib/jvm/java-8-oracle/jre/lib/ext/zipfs.jar:/usr/lib/jvm/java-8-oracle/jre/lib/javaws.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jce.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jfr.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jfxswt.jar:/usr/lib/jvm/java-8-oracle/jre/lib/jsse.jar:/usr/lib/jvm/java-8-oracle/jre/lib/management-agent.jar:/usr/lib/jvm/java-8-oracle/jre/lib/plugin.jar:/usr/lib/jvm/java-8-oracle/jre/lib/resources.jar:/usr/lib/jvm/java-8-oracle/jre/lib/rt.jar:/home/shubham/IdeaProjects/FirstJavaFx/out/production/FirstJavaFx sample.Main
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.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
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:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.control.MenuItem.fire(MenuItem.java:462)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.doSelect(ContextMenuContent.java:1405)
at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.lambda$createChildren$343(ContextMenuContent.java:1358)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
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.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$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$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$353(GlassViewEventHandler.java:432)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:431)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at com.sun.glass.ui.gtk.GtkApplication.lambda$null$48(GtkApplication.java:139)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771)
... 43 more
Caused by: java.lang.NullPointerException
at sample.Controller.editSaveAs(Controller.java:45)
... 53 more