我被困住了，需要一些建议。我在TextField和PasswordField上调用getText时不断获取NullPointerExceptions。我也使用fxml文件来创建UI和场景构建器。
代码：
public class LoginScreenController {
private Model model;
private final String userName = "Kazam";
private final String userPassword = "Kazam420";
@FXML
TextField login_txt;
@FXML
PasswordField password_txt;
@FXML
private MainScreenController mainscreencontroller;
@FXML
Pane loginScreen;
@FXML
public void Login() {
/* FXMLLoader loader = new FXMLLoader(getClass().getResource("/fxml/Options.fxml"));
Pane pane = null;
String name = login_txt.getText();
String password = password_txt.getText();
if (name.equals(userName) && password.equals(userPassword)) {
try {
pane = loader.load();
} catch (IOException ex) {
ex.printStackTrace();
}
OptionsScreenController optionsScreenController = loader.getController();
optionsScreenController.setMainScreenController(mainscreencontroller);
mainscreencontroller.setScreen(pane);
}*/
model.login();
}
public void setScreen(Pane pane){
loginScreen.getChildren().clear();
loginScreen.getChildren().add(pane);
}
public void setMainScreenController(MainScreenController mainscreencontroller) {
this.mainscreencontroller = mainscreencontroller;
}
public String getPassword(PasswordField password_txt){
String password = password_txt.getText();
return password;
}
public String getLogin(TextField login_txt) {
String login = login_txt.getText();
return login;
}
}
public class Model {
private LoginScreenController loginScreenController;
private final String userName = "Kazam";
private final String userPassword = "Kazam420";
@FXML
private MainScreenController mainscreencontroller;
@FXML
private TextField login_txt;
@FXML
private PasswordField password_txt;
String name = loginScreenController.getLogin(login_txt);
String password = loginScreenController.getPassword(password_txt);
public void login(){
FXMLLoader loader = new FXMLLoader(getClass().getResource("/fxml/Options.fxml"));
Pane pane;
if (name.equals(userName) && password.equals(userPassword) ){
try {
pane = loader.load();
mainscreencontroller.setScreen(pane);
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
}
控制器中的注释代码工作正常。我想把这个逻辑放在我的模型中。如果我做错了，请保持温和。我是编码和stackoverflow的初学者。 StackTrace：
Exception in thread "JavaFX Application Thread" java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1774)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Node.fireEvent(Node.java:8413)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Scene$MouseHandler.process(Scene.java:3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:381)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:417)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:416)
at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
at com.sun.glass.ui.View.notifyMouse(View.java:937)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java:275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java:1771)
... 45 more
Caused by: java.lang.NullPointerException
at Controllers.LoginScreenController.Login(LoginScreenController.java:61)
... 55 more
------------------------------------------------------------------------
BUILD SUCCESS
------------------------------------------------------------------------
Total time: 15.783s
Finished at: Mon May 22 15:36:21 CEST 2017
Final Memory: 20M/182M
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