我试图通过使用fxml进行布局来在另一个阶段使用搜索框。 它显示绝对正确，但它不会对任何事件做出反应。似乎找不到元素。
我的代码出了什么问题？
import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.stage.*;
import javafx.scene.*;
import javafx.scene.control.Button;
import javafx.scene.control.CheckBox;
import javafx.scene.control.Label;
import javafx.scene.control.Tab;
import javafx.scene.control.TabPane;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
public class SearchBox{
//tabs
@FXML
private static TabPane frepl_tabPane=new TabPane();
@FXML
private static Tab frepl_tabReplace=new Tab();
@FXML
private static Tab frepl_tabSearch=new Tab();
//search
//search Controls
@FXML
private static TextField fr_searchInput=new Textfield();
@FXML
private static Button fr_find=new Button();
private static Stage stage = new Stage();
public static void display(String title) throws IOException {
Parent root = FXMLLoader.load(SearchBox.class.getResource("find_replace.fxml"));
Scene scene = new Scene(root);
stage.setTitle(title);
stage.setScene(scene);
stage.showAndWait();
frepl_tabPane.getSelectionModel().selectedItemProperty().addListener((obs,ov,nv)->{
//no reaction here
stage.setTitle(nv.getText());
System.out.println("pane was tabbed");
});
fr_find.setOnMouseClicked(e ->{
//no reaction here
System.out.println("search");
});
}
要打开它我使用（＃34;初始化＆＃34;另一个FXMLDocumentControler的功能）：
btn_search.setOnMouseClicked(e->{
try {
SearchBox.display("search");
} catch (IOException ex) {
Logger.getLogger(FXMLDocumentController.class.getName()).log(Level.SEVERE, null, ex);
}
});
这是堆栈跟踪（当所有内容都是非静态的时，例如类，方法和字段）。当我关上窗户时，它会出现。
Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at SearchBox.display(SearchBox.java:133)
at FXMLDocumentController.lambda$A_table_buttons$22(FXMLDocumentController.java:1309)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$ClickGenerator.postProcess(Scene.java:3470)
at javafx.scene.Scene$ClickGenerator.access$8100(Scene.java:3398)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3766)
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$MouseEventNotification.run(GlassViewEventHandler.java:352)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:275)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:388)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:387)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
at java.lang.Thread.run(Thread.java:745)
FXML文件：
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.text.*?>
<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>
<Pane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="508.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1">
<children>
<TabPane fx:id="frepl_tabPane" layoutX="-1.0" layoutY="2.0" prefHeight="400.0" prefWidth="508.0" tabClosingPolicy="UNAVAILABLE">
<tabs>
<Tab fx:id="frepl_tabSearch" text="Search">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="180.0" prefWidth="200.0">
<children>
<TableView fx:id="fr_Stableview" layoutY="87.0" prefHeight="287.0" prefWidth="508.0">
<columns>
<TableColumn fx:id="fr_Sline" editable="false" prefWidth="75.0" sortable="false" text="Line" />
<TableColumn fx:id="fr_SColumn" editable="false" prefWidth="61.0" sortable="false" text="Column" />
<TableColumn fx:id="fr_SValue" editable="false" prefWidth="371.0" sortable="false" text="Value" />
</columns>
</TableView>
<TextField fx:id="fr_searchInput" layoutX="66.0" layoutY="13.0" prefHeight="25.0" prefWidth="250.0" />
<Label layoutX="3.0" layoutY="17.0" text="Search for:" />
<Button fx:id="fr_find" layoutX="324.0" layoutY="13.0" mnemonicParsing="false" text="Find" />
<Button fx:id="fr_findAll" layoutX="372.0" layoutY="13.0" mnemonicParsing="false" text="Find All" />
<CheckBox fx:id="fr_matchCaseS" layoutX="324.0" layoutY="53.0" mnemonicParsing="false" text="Match case (Aa)" />
<Label fx:id="fr_foundS" layoutX="8.0" layoutY="70.0" text="found: 5" underline="true">
<font>
<Font name="System Bold Italic" size="12.0" />
</font>
</Label>
</children>
</AnchorPane>
</content>
</Tab>
<Tab fx:id="frepl_tabReplace" text="Replace">
<content>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="180.0" prefWidth="200.0">
<children>
<TableView fx:id="fr_tableviewR" layoutY="107.0" prefHeight="267.0" prefWidth="508.0">
<columns>
<TableColumn fx:id="fr_lineR" prefWidth="75.0" text="Line" />
<TableColumn fx:id="fr_ColumnR" prefWidth="61.0" text="Column" />
<TableColumn fx:id="fr_ValueR" prefWidth="371.0" text="Value" />
</columns>
</TableView>
<CheckBox fx:id="fr_matchCaseR" layoutX="347.0" layoutY="59.0" mnemonicParsing="false" text="Match case (Aa)" />
<Label layoutX="3.0" layoutY="17.0" text="Search for:" />
<Button fx:id="fr_replace" layoutX="347.0" layoutY="11.0" mnemonicParsing="false" text="Replace" />
<TextField fx:id="fr_replaceInput" layoutX="82.0" layoutY="13.0" prefHeight="25.0" prefWidth="250.0" />
<Button fx:id="fr_replaceAll" layoutX="412.0" layoutY="11.0" mnemonicParsing="false" text="Replace All" />
<TextField fx:id="fr_replaceAllInput" layoutX="82.0" layoutY="55.0" prefHeight="25.0" prefWidth="250.0" />
<Label layoutX="3.0" layoutY="59.0" text="Replace with:" />
<Label fx:id="fr_replacedR" layoutX="3.0" layoutY="90.0" text="replaced: 5" underline="true">
<font>
<Font name="System Bold Italic" size="12.0" />
</font>
</Label>
</children>
</AnchorPane>
</content>
</Tab>
</tabs>
</TabPane>
</children>
</Pane>