我试图获取并销毁我在 FXML 应用程序关闭中通过 ProcessBuilder 创建的外部进程,但它不起作用。这是基于有用的建议谢尔盖·格里涅夫给了我这里.
我尝试过使用/不使用“// myController.setApp(this);”来运行并使用“// super.stop();”在子类的顶部和底部(请参阅 MyApp 中该行的注释掉/注释),但没有组合有效。
这可能与 FXML 或 JavaFX 无关,尽管我认为这是在 JavaFX 上开发应用程序的常见模式。我想我正在寻求一种 Java 最佳实践,用于在像这样的基于 UI 的应用程序中关闭相关进程(在本例中:基于 FXML / JavaFX),其中有一个控制器类和一个应用程序类。
你能解释一下我做错了什么吗?或者更好:建议我什么should而是做什么?谢谢。
在我的应用程序中我这样做:
public class MyApp extends Application {
@Override
public void start(Stage primaryStage) throws Exception {
FXMLLoader fxmlLoader = new FXMLLoader();
Scene scene = (Scene)FXMLLoader.load(getClass().getResource("MyApp.fxml"));
MyAppController myController = (MyAppController)fxmlLoader.getController();
primaryStage.setScene(scene);
primaryStage.show();
// myController.setApp(this);
}
@Override
public void stop() throws Exception {
// super.stop();
// this is called on fx app close, you may call it in an action handler too
if (MyAppController.getScriptProcess() != null) {
MyAppController.getScriptProcess().destroy();
}
super.stop();
}
public static void main(String[] args) {
launch(args);
}
}
在我的控制器中我这样做:
public class MyAppController implements Initializable {
private Application app;
private static Process scriptProcess;
public void setApp(Application a) {
app = a;
}
public static Process getScriptProcess() {
return scriptProcess;
}
}
当我使用“注释掉的 setApp()”运行时的结果not注释掉(即留在启动方法中),启动后立即如下(主场景闪烁,然后消失,然后出现此对话框:
"JavaFX Launcher Error:
Exception while running Application"
它还在控制台中给出了“应用程序启动方法中的异常”。
当我在上面的 MyApp 中省略“注释掉的代码”(即从启动方法中删除“setApp()”)时,结果是我的应用程序does确实关闭了,但是关闭时出现此错误:
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1440)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:69)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:28)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.Node.fireEvent(Node.java:6863)
at javafx.scene.control.Button.fire(Button.java:179)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:193)
at com.sun.javafx.scene.control.skin.SkinBase$4.handle(SkinBase.java:336)
at com.sun.javafx.scene.control.skin.SkinBase$4.handle(SkinBase.java:329)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:64)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:217)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:170)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:38)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:37)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:35)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:92)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:53)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:33)
at javafx.event.Event.fireEvent(Event.java:171)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3324)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3164)
at javafx.scene.Scene$MouseHandler.access$1900(Scene.java:3119)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1559)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2261)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:228)
at com.sun.glass.ui.View.handleMouseEvent(View.java:528)
at com.sun.glass.ui.View.notifyMouse(View.java:922)
at com.sun.glass.ui.gtk.GtkApplication._runLoop(Native Method)
at com.sun.glass.ui.gtk.GtkApplication$3$1.run(GtkApplication.java:82)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1435)
... 44 more
Caused by: java.lang.NullPointerException
at mypackage.MyController.handleCancel(MyController.java:300)
... 49 more
Clean up...