JavaFX WebView: how do I change the default cursor?

问题

How do I change WebView's default cursor? Every change I make is ignored, the icon always reverts back to the default pointer.

Example:

import javafx.application.Application;
import javafx.scene.Cursor;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class Main extends Application {
    public static void main(String[] args) {
        launch(args);
    }

    public void start(Stage primaryStage) {
        primaryStage.setTitle("JavaFX WebView Example");

        WebView webView = new WebView();
        webView.getEngine().loadContent("http://google.com");

        VBox vBox = new VBox(webView);
        Scene scene = new Scene(vBox, 960, 600);

        scene.setCursor(Cursor.CLOSED_HAND); // Doesn't work, reverted to pointer
        primaryStage.setScene(scene);
        primaryStage.show();
    }
}

I also tried to change the webView cursor itself, but to no avail.

回答1:

The document’s HTML content defines the cursor, so you can modify the document’s body style after it loads:

import org.w3c.dom.Document;
import org.w3c.dom.Element;

import javafx.application.Application;
import javafx.concurrent.Worker;
import javafx.scene.Scene;
import javafx.scene.layout.VBox;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class WebViewCursorOverride extends Application {
    public static void main(String[] args) {
        launch(args);
    }
    public void start(Stage primaryStage) {
        primaryStage.setTitle("JavaFX WebView Example");

        WebView webView = new WebView();
        webView.getEngine().getLoadWorker().stateProperty().addListener(
            (o, old, state) -> {
                if (state != Worker.State.SUCCEEDED) {
                    return;
                }

                Document doc = webView.getEngine().getDocument();
                Element body = (Element)
                    doc.getElementsByTagName("body").item(0);
                String style = body.getAttribute("style");
                body.setAttribute("style", "cursor: grab;" + style);
            });
        webView.getEngine().load("https://google.com");

        VBox vBox = new VBox(webView);
        Scene scene = new Scene(vBox, 960, 600);

        primaryStage.setScene(scene);
        primaryStage.show();
    }
}

You can also create your own cursor from an image:

body.setAttribute("style",
    "cursor: url('https://upload.wikimedia.org/wikipedia/commons/thumb/8/8c/Pixel_51_icon_cursor_click_top_right.svg/36px-Pixel_51_icon_cursor_click_top_right.svg.png') 27 9, default;" + style);

The full definition of the cursor CSS property is here. Here is the current list of predefined cursors; note that not all of them are supported on every system:

auto
default
none
context-menu
help
pointer
progress
wait
cell
crosshair
text
vertical-text
alias
copy
move
no-drop
not-allowed
grab
grabbing
e-resize
n-resize
ne-resize
nw-resize
s-resize
se-resize
sw-resize
w-resize
ew-resize
ns-resize
nesw-resize
nwse-resize
col-resize
row-resize
all-scroll
zoom-in
zoom-out

回答2:

The solution by @VGR is elegant, but induces flickering on my machine.

A more drastic solution is replacing the CursorManager used by WebEngine by something else.

For example, in Java10 you can create this CursorManagerImpl2 class based on the default CursorManagerImpl:

import com.sun.webkit.CursorManager;
import com.sun.webkit.graphics.WCGraphicsManager;
import com.sun.webkit.graphics.WCImage;

import javafx.application.Application;
import javafx.scene.Cursor;
import javafx.scene.ImageCursor;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.scene.layout.VBox;
import javafx.scene.web.WebView;
import javafx.stage.Stage;
import java.util.*;

public class CursorManagerImpl2 extends CursorManager<javafx.scene.Cursor> {
    private final Map<String, javafx.scene.Cursor> map = new HashMap();
    private ResourceBundle bundle;
    private javafx.scene.Cursor defaultCursor = javafx.scene.Cursor.DEFAULT;

    public CursorManagerImpl2() {}

    public CursorManagerImpl2(javafx.scene.Cursor defaultCursor) {
      this.defaultCursor = defaultCursor;
    }

    public javafx.scene.Cursor getDefaultCursor() {
      return defaultCursor;
    }

    public void setDefaultCursor(javafx.scene.Cursor cursor) {
      defaultCursor = cursor;
    }

    @Override
    protected javafx.scene.Cursor getCustomCursor(WCImage image, int hotspotX, int hotspotY) {
      return new ImageCursor(
          com.sun.javafx.tk.Toolkit.getImageAccessor()
              .fromPlatformImage(WCGraphicsManager.getGraphicsManager().toPlatformImage(image)),
          hotspotX,
          hotspotY);
    }
    @Override
    protected javafx.scene.Cursor getPredefinedCursor(int type) {
      switch (type) {
        case 0:
        default: return defaultCursor; // line changed
        case 1: return javafx.scene.Cursor.CROSSHAIR;
        case 2: return javafx.scene.Cursor.HAND;
        case 3: return javafx.scene.Cursor.MOVE;
        case 4: return javafx.scene.Cursor.TEXT;
        case 5: return javafx.scene.Cursor.WAIT;
        case 6: return this.getCustomCursor("help", javafx.scene.Cursor.DEFAULT);
        case 7: return javafx.scene.Cursor.E_RESIZE;
        case 8: return javafx.scene.Cursor.N_RESIZE;
        case 9: return javafx.scene.Cursor.NE_RESIZE;
        case 10: return javafx.scene.Cursor.NW_RESIZE;
        case 11: return javafx.scene.Cursor.S_RESIZE;
        case 12: return javafx.scene.Cursor.SE_RESIZE;
        case 13: return javafx.scene.Cursor.SW_RESIZE;
        case 14: return javafx.scene.Cursor.W_RESIZE;
        case 15: return javafx.scene.Cursor.V_RESIZE;
        case 16: return javafx.scene.Cursor.H_RESIZE;
        case 17: return this.getCustomCursor("resize.nesw", javafx.scene.Cursor.DEFAULT);
        case 18: return this.getCustomCursor("resize.nwse", javafx.scene.Cursor.DEFAULT);
        case 19: return this.getCustomCursor("resize.column", javafx.scene.Cursor.H_RESIZE);
        case 20: return this.getCustomCursor("resize.row", javafx.scene.Cursor.V_RESIZE);
        case 21: return this.getCustomCursor("panning.middle", javafx.scene.Cursor.DEFAULT);
        case 22: return this.getCustomCursor("panning.east", javafx.scene.Cursor.DEFAULT);
        case 23: return this.getCustomCursor("panning.north", javafx.scene.Cursor.DEFAULT);
        case 24: return this.getCustomCursor("panning.ne", javafx.scene.Cursor.DEFAULT);
        case 25: return this.getCustomCursor("panning.nw", javafx.scene.Cursor.DEFAULT);
        case 26: return this.getCustomCursor("panning.south", javafx.scene.Cursor.DEFAULT);
        case 27: return this.getCustomCursor("panning.se", javafx.scene.Cursor.DEFAULT);
        case 28: return this.getCustomCursor("panning.sw", javafx.scene.Cursor.DEFAULT);
        case 29: return this.getCustomCursor("panning.west", javafx.scene.Cursor.DEFAULT);
        case 30: return this.getCustomCursor("vertical.text", javafx.scene.Cursor.DEFAULT);
        case 31: return this.getCustomCursor("cell", javafx.scene.Cursor.DEFAULT);
        case 32: return this.getCustomCursor("context.menu", javafx.scene.Cursor.DEFAULT);
        case 33: return this.getCustomCursor("no.drop", javafx.scene.Cursor.DEFAULT);
        case 34: return this.getCustomCursor("not.allowed", javafx.scene.Cursor.DEFAULT);
        case 35: return this.getCustomCursor("progress", javafx.scene.Cursor.WAIT);
        case 36: return this.getCustomCursor("alias", javafx.scene.Cursor.DEFAULT);
        case 37: return this.getCustomCursor("zoom.in", javafx.scene.Cursor.DEFAULT);
        case 38: return this.getCustomCursor("zoom.out", javafx.scene.Cursor.DEFAULT);
        case 39: return this.getCustomCursor("copy", javafx.scene.Cursor.DEFAULT);
        case 40: return javafx.scene.Cursor.NONE;
        case 41: return this.getCustomCursor("grab", javafx.scene.Cursor.OPEN_HAND);
        case 42: return this.getCustomCursor("grabbing", javafx.scene.Cursor.CLOSED_HAND);
      }
    }

    private javafx.scene.Cursor getCustomCursor(String cursorId, javafx.scene.Cursor defaultCursor) {
      javafx.scene.Cursor customCursor = this.map.get(cursorId);
      if (customCursor == null) {
        try {
          if (this.bundle == null) {
            this.bundle =
                ResourceBundle.getBundle("com.sun.javafx.webkit.Cursors", Locale.getDefault());
          }

          if (this.bundle != null) {
            String fileName = this.bundle.getString(cursorId + ".file");
            javafx.scene.image.Image image =
                new Image(com.sun.javafx.webkit.CursorManagerImpl.class.getResourceAsStream(fileName));
            fileName = this.bundle.getString(cursorId + ".hotspotX");
            int hotspotX = Integer.parseInt(fileName);
            fileName = this.bundle.getString(cursorId + ".hotspotY");
            int hotspotY = Integer.parseInt(fileName);
            customCursor = new ImageCursor(image, hotspotX, hotspotY);
          }
        } catch (MissingResourceException e) {
        }

        if (customCursor == null) {
          customCursor = defaultCursor;
        }

        this.map.put(cursorId, customCursor);
      }

      return customCursor;
    }
}

You can then replace the manager with

CursorManager.setCursorManager(new CursorManagerImpl2(javafx.scene.Cursor.CROSSHAIR));

To change the default cursor, you can use

((CursorManagerImpl2) CursorManager.getCursorManager()).setDefaultCursor(javafx.scene.Cursor.MOVE);

Note that you might have to add the com.sun packages to your gradle:

compileJava {
    options.compilerArgs.addAll(['--add-exports=javafx.web/com.sun.webkit=ALL-UNNAMED', '--add-exports=javafx.web/com.sun.javafx.webkit=ALL-UNNAMED', '--add-exports=javafx.web/com.sun.webkit.graphics=ALL-UNNAMED', '--add-exports=javafx.graphics/com.sun.javafx.tk=ALL-UNNAMED'])
}
run {
    jvmArgs = ['--add-exports=javafx.web/com.sun.webkit=ALL-UNNAMED', '--add-exports=javafx.web/com.sun.javafx.webkit=ALL-UNNAMED', '--add-exports=javafx.web/com.sun.webkit.graphics=ALL-UNNAMED', '--add-exports=javafx.graphics/com.sun.javafx.tk=ALL-UNNAMED']
}

With this, I do not suffer from any flickering while moving the mouse, even when using large custom cursors.

The big downside (beside the com.sun imports) is that the CursorManager is static; as such, all WebViews will use the same cursor management.

来源：https://stackoverflow.com/questions/61021849/javafx-webview-how-do-i-change-the-default-cursor

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