JavaFX 问题与始终可见的日期选择器

Question

我正在尝试创建一个始终打开（弹出窗口）的日期选择器。所以我从 githhub 链接 https://gist.github.com/flasheater/ba58d5adffa1324e727e 那里得到了一个工作代码。但我的问题是当我在我的控制器类上实现此代码时，它显示错误。所以我想在下面发布我的完整代码。

FXMLDocumentController.java

  public class FXMLDocumentController implements Initializable {
  @FXML
  private AnchorPane bp;
  @Override
  public void initialize(URL url, ResourceBundle rb) {
    final DatePicker date_picker = new DatePicker();
    StackPane root=new StackPane(date_picker);
    date_picker.setVisible( false );
    date_picker.setManaged( false );
   final com.sun.javafx.scene.control.skin.DatePickerSkin skin = (com.sun.javafx.scene.control.skin.DatePickerSkin) date_picker.getSkin();
   root.getChildren().add(skin.getPopupContent()); 
   //added to stackpane.I think above line is having problem
   bp.getChildren().add(root); //added to anchorpane which already designed via scenebuilder
}
}

FXMLDocument.fxml（通过scenebuilder2.0设计）

 <?xml version="1.0" encoding="UTF-8"?>
 <?import java.lang.*?>
 <?import java.util.*?>
 <?import javafx.scene.*?>
 <?import javafx.scene.control.*?>
 <?import javafx.scene.layout.*?>
 <AnchorPane fx:id="bp" prefHeight="443.0" prefWidth="563.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="tableviewmodalbaseview.FXMLDocumentController" />

错误如下

Exception in Application start method
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:497)
at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
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:497)
at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:323)
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:497)
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:917)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$152(LauncherImpl.java:182)
at com.sun.javafx.application.LauncherImpl$$Lambda$51/17398621.run(Unknown Source)
at java.lang.Thread.run(Thread.java:745)

Caused by: javafx.fxml.LoadException: 
    file:/C:/Users/aboosidhu/Documents/NetBeansProjects/TableViewModalBaseView/dist/run1705880335/TableViewModalBaseView.jar!/tableviewmodalbaseview/FXMLDocument.fxml
at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2605)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2583)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2445)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3218)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3179)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3152)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3128)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3108)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3101)
at tableviewmodalbaseview.TableCellFactorySample.start(TableCellFactorySample.java:46)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$159(LauncherImpl.java:863)
at com.sun.javafx.application.LauncherImpl$$Lambda$54/31372366.run(Unknown Source)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$172(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl$$Lambda$46/22256815.run(Unknown Source)
at com.sun.javafx.application.PlatformImpl.lambda$null$170(PlatformImpl.java:295)
at com.sun.javafx.application.PlatformImpl$$Lambda$49/23180581.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$171(PlatformImpl.java:294)
at com.sun.javafx.application.PlatformImpl$$Lambda$48/265996.run(Unknown Source)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$145(WinApplication.java:101)
at com.sun.glass.ui.win.WinApplication$$Lambda$37/23703675.run(Unknown Source)
... 1 more

 Caused by: java.lang.NullPointerException
at tableviewmodalbaseview.FXMLDocumentController.initialize(FXMLDocumentController.java:151)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2552)
... 22 more

所以任何人都可以帮助我修复我的代码错误。任何答案将不胜感激。

Answer 1

我不知道

你到底想实现什么，但我没有看到在这里使用Cast的兴趣：

final com.sun.javafx.scene.control.skin.DatePickerSkin skin = (com.sun.javafx.scene.control.skin.DatePickerSkin) date_picker.getSkin();

为什么不直接使用带有DatePicker的实例作为参数：

final DatePickerSkin skin = new DatePickerSkin(date_picker); 

尝试正确导入您的组件，祝你好运！