我正在用javafx编写程序，但无法解决我的错误。 java.lang.reflect.InvocationTargetException
我已经在此页面上对此进行了搜索，但是我无法解决此问题...
这是我在MlCalcController.java中的代码
public class MlCalcController implements Initializable {
@FXML
private Label FirstOneName;
private TextField FirName;
private TextField FirMl;
private TextField FirPrice;
private TextField FirPerprice;
public void CalculateButtonAction (ActionEvent event) throws IOException{
FXMLLoader loader = new FXMLLoader(getClass().getResource("MlCalc.fxml"));
String name = FirName.getText();
int ml = Integer.parseInt(FirMl.getText());
int price = Integer.parseInt(FirPrice.getText());
int div, sum;
div = ml/100;
sum = price/div;
FirPerprice.setText(String.valueOf(sum));
FirstOneName.setText(name);
}
这是fxml代码
<AnchorPane id="AnchorPane" prefHeight="480.0" prefWidth="720.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="jproject.MlCalcController">
<children>
<HBox alignment="CENTER" layoutX="313.0" layoutY="369.0" prefHeight="35.0" prefWidth="287.0" AnchorPane.bottomAnchor="15.0" AnchorPane.rightAnchor="10.0">
<children>
<Button fx:id="CalculateButton" onAction="#CalculateButtonAction" prefHeight="35.0" prefWidth="75.0" text="Calculation">
<HBox.margin>
<Insets left="10.0" right="10.0" />
</HBox.margin></Button>
<Button mnemonicParsing="false" prefHeight="35.0" prefWidth="75.0" text="Compare">
<HBox.margin>
<Insets left="10.0" right="10.0" />
</HBox.margin></Button>
<Button mnemonicParsing="false" prefHeight="35.0" prefWidth="75.0" text="Go Home">
<HBox.margin>
<Insets left="10.0" />
</HBox.margin></Button>
</children>
<HBox layoutX="36.0" layoutY="76.0" prefHeight="35.0" prefWidth="635.0">
<children>
<TextField fx:id="FirName" prefHeight="54.0" prefWidth="93.0">
<HBox.margin>
<Insets right="20.0" />
</HBox.margin>
</TextField>
<TextField fx:id="FirMl" prefHeight="54.0" prefWidth="93.0">
<HBox.margin>
<Insets right="20.0" />
</HBox.margin>
</TextField>
<TextField fx:id="FirPrice" prefHeight="54.0" prefWidth="93.0">
<HBox.margin>
<Insets right="140.0" />
</HBox.margin>
</TextField>
<TextField fx:id="FirPerprice" prefHeight="35.0" prefWidth="143.0" />
</children>
</HBox>
<Label fx:id="FirstOneName" layoutX="36.0" layoutY="224.0" prefHeight="64.0" prefWidth="268.0" text="Label" />
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 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:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Node.fireEvent(Node.java:8411)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$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.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$353(GlassViewEventHandler.java:432)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:431)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$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:1769)
... 48 more
Caused by: java.lang.NullPointerException
at jproject.MlCalcController.CalculateButtonAction(MlCalcController.java:34)
... 58 more
我想计算每100毫升的饮料价格。 这是例子 第一次喝的水1000毫升是20美元。 这款饮料每100毫升2美元。 我想要这样的结果。