Question

我在使用JavaFx ImageView时遇到问题，每次尝试访问时都会给我一个NullPointerExecption，这就是我所做的，首先我在FXML中设置它喜欢 <ImageView fx:id="img_MainScreen" fitHeight="240.0" fitWidth="360.0" pickOnBounds="true"></ImageView>并在ControllerClass中添加了FXML标记，并创建了@FXML private ImageView img_MainScreen之类的对象，之后我进入initialize()并尝试打印出FitHeight and FitWidth并尝试设置一个图像，因为我知道该方法只在所有视图初始化后调用，所以我这样做

public void imageProcessor(ImageView screen)
{
    Thread mainThread = new Thread (new Runnable()
            {

                @Override
                public void run() {
                    // TODO Auto-generated method stub


                    try{
                    System.out.println("height of ImageView: "+screen.getFitHeight());
                    System.out.println("Width of ImageView: "+screen.getFitWidth());

                    }catch(Exception e)
                    {
                        e.printStackTrace();
                    }

                }

            });mainThread.start();

}


  Jan 20, 2016 11:32:56 AM loginManager.LoginManager showMainView
SEVERE: null
 javafx.fxml.LoadException: 
  /C:/xx/xx/xx/xx/xx/xxx/mainWindow.fxml

at javafx.fxml.FXMLLoader.constructLoadException(Unknown Source)
at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
at javafx.fxml.FXMLLoader.loadImpl(Unknown Source)
at javafx.fxml.FXMLLoader.load(Unknown Source)
at loginManager.LoginManager.showMainView(LoginManager.java:184)
at loginManager.LoginManager.authenticated(LoginManager.java:50)
at application.LoginController$1.handle(LoginController.java:67)
at application.LoginController$1.handle(LoginController.java:1)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
at javafx.event.Event.fireEvent(Unknown Source)
at javafx.scene.Node.fireEvent(Unknown Source)
at javafx.scene.control.Button.fire(Unknown Source)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(Unknown Source)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(Unknown Source)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEventImpl(Unknown Source)
at com.sun.javafx.event.EventUtil.fireEvent(Unknown Source)
at javafx.event.Event.fireEvent(Unknown Source)
at javafx.scene.Scene$MouseHandler.process(Unknown Source)
at javafx.scene.Scene$MouseHandler.access$1500(Unknown Source)
at javafx.scene.Scene.impl_processMouseEvent(Unknown Source)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(Unknown Source)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(Unknown Source)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.handleMouseEvent(Unknown Source)
at com.sun.glass.ui.View.notifyMouse(Unknown Source)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.reflect.misc.Trampoline.invoke(Unknown Source)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at sun.reflect.misc.MethodUtil.invoke(Unknown Source)
... 58 more
 Caused by: java.lang.NullPointerException
at application.MainViewController.initialize(MainViewController.java:73)
... 67 more

Answer 1

您的fxml无法加载。

  Jan 20, 2016 11:32:56 AM loginManager.LoginManager showMainView
SEVERE: null
 javafx.fxml.LoadException: 
  /C:/xx/xx/xx/xx/xx/xxx/mainWindow.fxml

除非您提供完整的代码，特别是如何加载它，否则没有人可以帮助您。

JavaFx ImageView给出nullpointerExeption

1 个答案: