我有一个按钮addProduct，它通过AddProducts方法获取一个动作来显示一个Dialog，以便向表中添加项目但是当我触发它时会出现很多错误，当我尝试显示其他对话框时，我会遇到同样的问题将其他项添加到其他表中。
addProduct.setOnAction(event -> {
try {
AddProducts(table);
} catch (IOException e) {
e.printStackTrace();
}
});
我有一个方法AddProducts，当我点击addProduct时它应该显示一个Dialog但它会引发这个异常。
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at com.sun.javafx.scene.control.skin.Utils.computeTextWidth(Utils.java:118)
at com.sun.javafx.scene.control.skin.LabeledSkinBase.computeMinLabeledPartWidth(LabeledSkinBase.java:661)
at com.sun.javafx.scene.control.skin.LabeledSkinBase.computeMinWidth(LabeledSkinBase.java:633)
at javafx.scene.control.Control.computeMinWidth(Control.java:470)
at javafx.scene.Parent.minWidth(Parent.java:943)
at javafx.scene.layout.Region.minWidth(Region.java:1383)
at javafx.scene.layout.Region.computeChildPrefAreaWidth(Region.java:1728)
at javafx.scene.layout.GridPane.computePrefWidths(GridPane.java:1556)
at javafx.scene.layout.GridPane.computePrefWidth(GridPane.java:1242)
at javafx.scene.Parent.prefWidth(Parent.java:915)
at javafx.scene.layout.Region.prefWidth(Region.java:1419)
at javafx.scene.control.DialogPane.computePrefWidth(DialogPane.java:973)
at javafx.scene.Parent.prefWidth(Parent.java:915)
at javafx.scene.layout.Region.prefWidth(Region.java:1419)
at javafx.scene.Scene.getPreferredWidth(Scene.java:1697)
at javafx.scene.Scene.resizeRootToPreferredSize(Scene.java:1673)
at javafx.scene.Scene.preferredSize(Scene.java:1645)
at javafx.scene.Scene.impl_preferredSize(Scene.java:1720)
at javafx.stage.Window$9.invalidated(Window.java:846)
at javafx.beans.property.BooleanPropertyBase.markInvalid(BooleanPropertyBase.java:109)
at javafx.beans.property.BooleanPropertyBase.set(BooleanPropertyBase.java:144)
at javafx.stage.Window.setShowing(Window.java:922)
at javafx.stage.Window.show(Window.java:937)
at javafx.stage.Stage.show(Stage.java:259)
at javafx.stage.Stage.showAndWait(Stage.java:472)
at javafx.scene.control.HeavyweightDialog.showAndWait(HeavyweightDialog.java:162)
at javafx.scene.control.Dialog.showAndWait(Dialog.java:341)
**at ddapp.TabsView.AddProducts(TabsView.java:825)
at ddapp.TabsView.lambda$ShowProductsTable$5(TabsView.java:432)**
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.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.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$MouseEventNotification.run(GlassViewEventHandler.java:380)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:294)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:416)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:415)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at com.sun.glass.ui.gtk.GtkApplication.lambda$null$49(GtkApplication.java:139)
at java.lang.Thread.run(Thread.java:745)
这是方法AddProducts：
public void AddProducts(final TableView<ProductsValues> table) throws IOException {
Dialog<ProductsValues> addP = new Dialog<>();
DialogPane dialogPane = addP.getDialogPane();
dialogPane.getStylesheets().add(getClass().getClassLoader().getResource("JMetroLightTheme.css").toExternalForm());
addP.setTitle("Añadir Producto");
addP.setHeaderText("Ingrese la información correspondiente al producto que desea añadir al inventario.");
addP.setResizable(false);
addP.initModality(APPLICATION_MODAL);
addP.initStyle(StageStyle.TRANSPARENT);
Label label2 = new Label(CODE);
label2.setFont(fontAwesome);
label2.setTextFill(Color.web("#4E0A07"));
JFXTextField text2 = new JFXTextField();
text2.setPromptText("Codigo Interno");
text2.setLabelFloat(true);
Label label1 = new Label(BARCODE);
label1.setFont(fontAwesome);
label1.setTextFill(Color.web("#4E0A07"));
JFXTextField text1 = new JFXTextField();
text1.setPromptText("Codigo de Barra");
text1.setLabelFloat(true);
Label label3 = new Label(INFO);
label3.setFont(fontAwesome);
label3.setTextFill(Color.web("#4E0A07"));
JFXTextField text3 = new JFXTextField();
text3.setPromptText("Descripción");
text3.setLabelFloat(true);
Label label4 = new Label(MARK);
label4.setFont(fontAwesome);
label4.setTextFill(Color.web("#4E0A07"));
JFXTextField text4 = new JFXTextField();
text4.setPromptText("Marca");
text4.setLabelFloat(true);
Label label5 = new Label(PACK);
label5.setFont(fontAwesome);
label5.setTextFill(Color.web("#4E0A07"));
JFXTextField text5 = new JFXTextField();
text5.setPromptText("Embalaje");
text5.setLabelFloat(true);
Label label6 = new Label(BOX);
label6.setFont(fontAwesome);
label6.setTextFill(Color.web("#4E0A07"));
JFXTextField text6 = new JFXTextField();
text6.setPromptText("Unidades por Paquete");
text6.setLabelFloat(true);
Label label7 = new Label(PRODUCT);
label7.setFont(fontAwesome);
label7.setTextFill(Color.web("#4E0A07"));
JFXTextField text7 = new JFXTextField();
text7.setPromptText("Precio Unitario");
text7.setLabelFloat(true);
Label label8 = new Label(USD);
label8.setFont(fontAwesome);
label8.setTextFill(Color.web("#4E0A07"));
JFXTextField text8 = new JFXTextField();
text8.setPromptText("Precio Paquete");
text8.setLabelFloat(true);
GridPane grid = new GridPane();
grid.add(label2, 1, 1);
grid.add(text2, 2, 1);
grid.setMargin(text2, new Insets(15, 0, 0, 0));
grid.setMargin(label2, new Insets(15, 0, 0, 0));
grid.add(label1, 1, 2);
grid.add(text1, 2, 2);
grid.setMargin(text1, new Insets(15, 0, 0, 0));
grid.setMargin(label1, new Insets(15, 0, 0, 0));
grid.add(label3, 1, 3);
grid.add(text3, 2, 3);
grid.setMargin(text3, new Insets(15, 0, 0, 0));
grid.setMargin(label3, new Insets(15, 0, 0, 0));
grid.add(label4, 1, 4);
grid.add(text4, 2, 4);
grid.setMargin(text4, new Insets(15, 0, 0, 0));
grid.setMargin(label4, new Insets(15, 0, 0, 0));
grid.add(label5, 1, 5);
grid.add(text5, 2, 5);
grid.setMargin(text5, new Insets(15, 0, 0, 0));
grid.setMargin(label5, new Insets(15, 0, 0, 0));
grid.add(label6, 1, 6);
grid.add(text6, 2, 6);
grid.setMargin(text6, new Insets(15, 0, 0, 0));
grid.setMargin(label6, new Insets(15, 0, 0, 0));
grid.add(label7, 1, 7);
grid.add(text7, 2, 7);
grid.setMargin(text7, new Insets(15, 0, 0, 0));
grid.setMargin(label7, new Insets(15, 0, 0, 0));
grid.add(label8, 1, 8);
grid.add(text8, 2, 8);
grid.setMargin(text8, new Insets(15, 0, 0, 0));
grid.setMargin(label8, new Insets(15, 0, 0, 0));
addP.getDialogPane().setContent(grid);
addP.initOwner(mainStage);
ButtonType buttonTypeOk = new ButtonType("Agregar", ButtonBar.ButtonData.OK_DONE);
addP.getDialogPane().getButtonTypes().add(buttonTypeOk);
ButtonType buttonTypeCancel = new ButtonType("Cancelar", ButtonBar.ButtonData.CANCEL_CLOSE);
addP.getDialogPane().getButtonTypes().add(buttonTypeCancel);
addP.setResultConverter(b -> {
if (b == buttonTypeOk) {
int nextIndex = table.getSelectionModel().getSelectedIndex();
table.getItems().add(nextIndex, new ProductsValues(text1.getText(), text2.getText(), text3.getText(), text4.getText(), text5.getText(), Integer.parseInt(text6.getText()), Double.parseDouble(text7.getText()), Double.parseDouble(text8.getText())));
table.getSelectionModel().select(nextIndex);
addP.close();
return new ProductsValues(text2.getText(), text1.getText(), text3.getText(), text4.getText(), text5.getText(), Integer.parseInt(text6.getText()), Double.parseDouble(text7.getText()), Double.parseDouble(text8.getText()));
} else
addP.close();
return null;
});
addP.showAndWait();
}
这是我的课程中的一行，它认为是错误：
addP.showAndWait();//825, when I show the Dialog
AddProducts(table);//432, when I call the method