java - 将 CSS 与 javaFX 链接

Question

我只是javafx的初学者。我已经使用场景构建器使用它，但现在我正在尝试在没有场景构建器的情况下学习基础知识。我在 netbeans 中执行以下代码。我包含的库文件是

package login;

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.scene.paint.Color;
import javafx.scene.text.Font;
import javafx.scene.text.FontWeight;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class Login extends Application {

    public void start(Stage primaryStage) {

        GridPane grid = new GridPane();
        grid.setAlignment(Pos.CENTER);
        grid.setHgap(10);
        grid.setVgap(10);
        grid.setPadding(new Insets(25,25,25,25));

        Scene scene = new Scene(grid, 300, 275);

        Text scenetitle = new Text("Please Login: ");
        scenetitle.setFont(Font.font("Tahoma",FontWeight.NORMAL, 20));
        Label userName = new Label("User Name:");
        TextField userTextField = new TextField();
        Label pw = new Label("Password: ");
        PasswordField pwBox = new PasswordField();

        grid.add(scenetitle,0,0,2,1);
        grid.add(userName,0,1);
        grid.add(userTextField, 1,1);
        grid.add(pw,0,2);
        grid.add(pwBox,1,2);

        grid.setGridLinesVisible(false);

        Button btn = new Button("Sign in");
        HBox hbBtn = new HBox(10);
        hbBtn.setAlignment(Pos.BOTTOM_RIGHT);
        hbBtn.getChildren().add(btn);
        grid.add(hbBtn,1,4);

        final Text actiontarget = new Text();
        grid.add(actiontarget,1,6);

        btn.setOnAction(event ->
        {
            actiontarget.setFill(Color.TURQUOISE);
            actiontarget.setText("Sign in button pressed");

        });
        scene.getStylesheets().
                add(Login.class.getResource("Login.css").toExternalForm());
        primaryStage.setTitle("JavaFX Login Form");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        launch(args);
    }

}

使用此类后，我使用以下 CSS 代码对程序进行样式设置

.root {-fx-background-image: url("background.png");}

.label {
    -fx-font-size: 12px;
    -fx-font-weight: bold;
    -fx-text-fill: #0E1D33;
}

#login-text{
    -fx-font-size:32px;
    -fx-font-family: "Arial Black";
    -fx-fill: #115E7F;
}

#actiontarget {
    -fx-fill:WHITE;
    -fx-font-weight:bold;
    
}
.button {
    -fx-text-fill:white;
    -fx-font-family:"Arial Narrow";
    -fx-font-weight:bold;
    -fx-background-color:linear-gradient(#61a2b1,#2A5058);
    
}

在应用程序启动方法中运行代码异常 java.lang.reflect.InvocationTargetException 后，它给了我以下异常

    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 com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
    at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
    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.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:767)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$154(LauncherImpl.java:182)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException
    at login.Login.start(Login.java:72)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    ... 1 more
Exception running application login.Login
E:\NetBean Projects\Java FX Lynda Following\Login\nbproject\build-impl.xml:1052: The following error occurred while executing this line:
E:\NetBean Projects\Java FX Lynda Following\Login\nbproject\build-impl.xml:806: Java returned: 1

标签： javacssjavafxnetbeans