我创建了一个类似窗格的卡片，以便我可以向其中添加数据并根据数据创建一个包含许多卡片的页面（很像移动应用程序中的卡片布局）但是，我不知道如何将它的新实例添加到 VBox . 我累了和没有循环，但仍然没有工作。它不断给出以下错误：
javafx.fxml.LoadException:
/C:///////bin/application/HotelReservation.fxml
at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2579)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
at application.Main.start(Main.java:18)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException: Children: child node is null: parent = VBox[id=vboxData]
at javafx.scene.Parent$2.onProposedChange(Parent.java:435)
at com.sun.javafx.collections.VetoableListDecorator.add(VetoableListDecorator.java:206)
at application.HotelReservationController.initialize(HotelReservationController.java:45)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
... 17 more
这是像 Pane 这样的卡片的 FXML 文件：
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.image.ImageView?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.layout.VBox?>
<?import javafx.scene.text.Font?>
<?import javafx.scene.text.Text?>
<AnchorPane fx:id="cardAnchor" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1">
<children>
<HBox fx:id="cardHBox" prefHeight="152.0" prefWidth="584.0">
<children>
<ImageView fx:id="cardPhoto" fitHeight="150.0" fitWidth="200.0" pickOnBounds="true" preserveRatio="true" />
<VBox prefHeight="200.0" prefWidth="100.0">
<children>
<Text fx:id="cardTitle" strokeType="OUTSIDE" strokeWidth="0.0" text="Ttile:" wrappingWidth="385.9830722808838">
<font>
<Font name="System Bold" size="31.0" />
</font>
</Text>
<HBox prefHeight="18.0" prefWidth="386.0">
<children>
<Text fx:id="cardLocation" strokeType="OUTSIDE" strokeWidth="0.0" text="Location:" wrappingWidth="211.9830722808838">
<font>
<Font name="System Bold" size="15.0" />
</font>
</Text>
<Text fx:id="cardRating" strokeType="OUTSIDE" strokeWidth="0.0" text="Rating:" wrappingWidth="172.9830722808838">
<font>
<Font name="System Bold" size="15.0" />
</font>
</Text>
</children>
</HBox>
<HBox prefHeight="100.0" prefWidth="200.0">
<children>
<Text fx:id="cardDescription" strokeType="OUTSIDE" strokeWidth="0.0" wrappingWidth="308.9830722808838" />
<Button fx:id="cardDetails" mnemonicParsing="false" prefHeight="89.0" prefWidth="79.0" text="Details" textAlignment="JUSTIFY" />
</children>
</HBox>
</children>
</VBox>
</children>
</HBox>
</children>
</AnchorPane>
这是 VBox 所在位置的 FXML：
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.ScrollPane?>
<?import javafx.scene.control.SplitPane?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.layout.VBox?>
<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="700.0" prefWidth="700.0" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="application.HotelReservationController">
<children>
<SplitPane dividerPositions="0.14630681818181818" layoutX="-2.0" layoutY="-2.0" orientation="VERTICAL" prefHeight="706.0" prefWidth="708.0">
<items>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="85.0" prefWidth="162.0" style="-fx-background-color: brown;">
<children>
<HBox layoutX="2.0" prefHeight="100.0" prefWidth="248.0" spacing="2.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="75.0">
<children>
<Button mnemonicParsing="false" style="-fx-background-color: #EE854E;" text="Home" />
<Button mnemonicParsing="false" style="-fx-background-color: #EE854E;" text="Hotels" />
<Button mnemonicParsing="false" style="-fx-background-color: #EE854E;" text="Cars" />
<Button mnemonicParsing="false" style="-fx-background-color: #EE854E;" text="Trips" />
</children>
</HBox>
</children>
</AnchorPane>
<AnchorPane minHeight="0.0" minWidth="0.0" prefHeight="508.0" prefWidth="673.0" style="-fx-background-color: orange;">
<children>
<ScrollPane fx:id="scrollPaneContent" layoutX="-1.0" layoutY="-2.0" prefHeight="605.0" prefWidth="708.0" style="-fx-background-color: orange;" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
<content>
<VBox fx:id="vboxData" prefHeight="176.0" prefWidth="705.0" style="-fx-background-color: orange;" />
</content></ScrollPane>
</children></AnchorPane>
</items>
</SplitPane>
</children>
</AnchorPane>
这是我在java中实现它的方式：
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.layout.AnchorPane;
public class Main extends Application {
public static void main(String[] args) {
launch(args);
}
@Override
public void start(Stage primaryStage) {
try {
AnchorPane root =(AnchorPane) FXMLLoader.load(Main.class.getResource("/application/HotelReservation.fxml"));
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.setTitle("Hotel Reservation");
primaryStage.show();
} catch(Exception e) {
e.printStackTrace();
}
}
}
......
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.ScrollPane;
import javafx.scene.layout.AnchorPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.text.Text;
public class HotelReservationController implements Initializable{
@FXML
private ScrollPane scrollPaneContent;
@FXML
private VBox vboxData;
@FXML
private AnchorPane cardAnchor;
@FXML
private HBox cardHBox;
@Override
public void initialize(URL arg0, ResourceBundle arg1) {
// TODO Auto-generated method stub
vboxData.setSpacing(5);
vboxData.getChildren().add(cardAnchor);
// for (int j = 0; j < 100; j++) {
// vboxData.getChildren().add(cardAnchor);
// }
}
HotelReservation.fxmlwith 中没有元素fx:id="cardAnchor"，因此cardAnchor控制器中为 null，并且您会在堆栈跟踪中看到空指针异常。
要“创建 FXML 的实例”，您需要加载 FXML。所以我认为你在这里尝试做的是：
public class HotelReservationController implements Initializable{
@FXML
private ScrollPane scrollPaneContent;
@FXML
private VBox vboxData;
@FXML
private HBox cardHBox;
@Override
public void initialize(URL arg0, ResourceBundle arg1) {
// unclear why you wouldn't do this in the FXML
vboxData.setSpacing(5);
// guessing at the path, will need to be set appropriately:
URL cardURL = getClass().getResource("/application/Card.fxml");
try {
for (int j = 0; j < 100; j++) {
Parent cardAnchor = FXMLLoader.load(cardURL);
vboxData.getChildren().add(cardAnchor);
}
} catch (IOException exc) {
exc.printStackTrace();
System.exit(1);
}
}
}
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