Question

我的程序有2个控制器，关闭一个控制器后，我想在TextArea中显示一些String。但是在调用方法后，我在Javafx Thread中得到了NullPointerException。我已经尝试了所有方法，是的，FXML变量已正确分配。

  public  void showIt(String message) {
    try{
    Platform.runLater(()->chatArea.appendText(message +"\n"));
  } catch(NullPointerException exc) {
   exc.printStackTrace();
 }
}

从第二类中调用显示方法的方法：

@FXML
void tryToConnect(ActionEvent event) throws IOException, InterruptedException {


    Thread t = new Thread(() -> {
        Socket socket = null;
        try {
            socket = new Socket("localhost", 6666);
            connectionStabilizer = new ConnectionStabilizer();
            connectionStabilizer.getConnection(socket);

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

    });
    t.start();

    MainWindowController mainWindowController = new MainWindowController();
    mainWindowController.showIt("works");
    cancelConnectionPanel(event);

}

错误消息：

       Exception in thread "JavaFX Application Thread" java.lang.NullPointerException
at sample.Controller.lambda$setClockLabel$1(Controller.java:60)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$9(PlatformImpl.java:418)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:417)
at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:175)
at java.base/java.lang.Thread.run(Thread.java:844)

调用方法时，线程“ JavaFX Application Thread”中的异常java.lang.NullPointerException

0 个答案: