我已经创建了一个基于FXML的自定义控件,其中又引用了另一个基于FXML的自定义控件。当我在Eclipse中加载它们时,它们都可以正常工作,但是当我尝试将它们导入到SceneBuilder中时,外部控件(包含另一个控件的控件)无法正确导入。
这里是一个大大简化的示例:
Widget.java:
package example;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.fxml.FXMLLoader;
import javafx.scene.layout.Pane;
public class Widget extends Pane{
public Widget() {
Logger logger = Logger.getLogger(Widget.class.getName());
try {
FXMLLoader loader= new FXMLLoader(Widget.class.getResource("Widget.fxml"));
Pane pane = loader.load();
this.getChildren().add(pane);
}
catch(Exception e) {
logger.log(Level.SEVERE, "Failed to load Widget", e);
}
}
}
Widget.fxml:
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.FlowPane?>
<?import javafx.scene.control.Label?>
<?import example.SubWidget?>
<FlowPane xmlns:fx="http://javafx.com/fxml/1" >
<children>
<Label text="Widget"/>
<SubWidget></SubWidget>
</children>
</FlowPane>
SubWidget.java:
package example;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.fxml.FXMLLoader;
import javafx.scene.layout.Pane;
public class SubWidget extends Pane{
public SubWidget() {
Logger logger = Logger.getLogger(SubWidget.class.getName());
try {
FXMLLoader loader= new FXMLLoader(SubWidget.class.getResource("SubWidget.fxml"));
Pane pane = loader.load();
this.getChildren().add(pane);
}
catch(Exception e) {
logger.log(Level.SEVERE, "Failed to load SubWidget", e);
}
}
}
SubWidget.fxml:
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.layout.FlowPane?>
<?import javafx.scene.control.Label?>
<FlowPane xmlns:fx="http://javafx.com/fxml/1" >
<children>
<Label text="Subwidget"/>
</children>
</FlowPane>
我将这些导出为jar文件,尝试通过SceneBuilder的jar导入功能进行导入。当我这样做时,
SubWidget
被成功导入并且看起来很好。 Widget
也会显示为控件,但它将完全为空。当我检查日志文件时,发现FXML加载器无法找到SubWidget类文件而导致这种情况。
Oct 29, 2020 4:28:30 PM example.Widget <init>
SEVERE: Failed to load Widget
javafx.fxml.LoadException:
file:/C:/Users/nate/AppData/Roaming/Scene%20Builder/Library/TestFxControl.jar!/example/Widget.fxml
at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
at javafx.fxml.FXMLLoader.importClass(FXMLLoader.java:2848)
at javafx.fxml.FXMLLoader.processImport(FXMLLoader.java:2692)
at javafx.fxml.FXMLLoader.processProcessingInstruction(FXMLLoader.java:2661)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2517)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
at example.Widget.<init>(Widget.java:27)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at java.lang.Class.newInstance(Unknown Source)
at sun.reflect.misc.ReflectUtil.newInstance(Unknown Source)
at javafx.fxml.FXMLLoader$InstanceDeclarationElement.constructValue(FXMLLoader.java:1009)
at javafx.fxml.FXMLLoader$ValueElement.processStartElement(FXMLLoader.java:746)
at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2707)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2527)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2425)
at com.oracle.javafx.scenebuilder.kit.library.util.JarExplorer.instantiateWithFXMLLoader(JarExplorer.java:110)
at com.oracle.javafx.scenebuilder.kit.library.util.JarExplorer.exploreEntry(JarExplorer.java:160)
at com.oracle.javafx.scenebuilder.kit.library.util.JarExplorer.explore(JarExplorer.java:70)
at com.oracle.javafx.scenebuilder.kit.library.user.LibraryFolderWatcher.exploreAndUpdateLibrary(LibraryFolderWatcher.java:325)
at com.oracle.javafx.scenebuilder.kit.library.user.LibraryFolderWatcher.runDiscovery(LibraryFolderWatcher.java:138)
at com.oracle.javafx.scenebuilder.kit.library.user.LibraryFolderWatcher.run(LibraryFolderWatcher.java:92)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassNotFoundException: example.SubWidget
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at javafx.fxml.FXMLLoader.loadTypeForPackage(FXMLLoader.java:2916)
at javafx.fxml.FXMLLoader.loadType(FXMLLoader.java:2905)
at javafx.fxml.FXMLLoader.importClass(FXMLLoader.java:2846)
... 24 more
在我看来,FXML加载器使用的类加载器不包括其他自定义组件,这很奇怪,因为如果我在Widget
类中绕过FXML并使其变成:
public class Widget extends FlowPane{
public Widget() {
this.getChildren().addAll(new Label("Widget"), new SubWidget());
}
}
然后在SceneBuilder中正常加载。因此,实际加载Widget
的ClassLoader
与FXMLLoader
使用的ClassLoader
不同。
这可能与这个未解答的问题有关,虽然它们并不完全相同。