检测 WebView 中的超链接悬停并打印链接

Question

我想从 WebView 添加悬停的超链接并将其显示在角落。

我该如何实现？它应该类似于 Chrome 的功能：

示例-Chrome-屏幕截图

包含许多链接的示例 WebView 代码：

import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.ScrollPane;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class core extends Application {
    @Override
    public void start(final Stage stage) {
        Scene scene = new Scene(new Group());

        final WebView browser = new WebView();
        final WebEngine webEngine = browser.getEngine();

        ScrollPane scrollPane = new ScrollPane();
        scrollPane.setContent(browser);

        webEngine.load("http://java2s.com");

        scene.setRoot(scrollPane);

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

    public static void main(String[] args) {
        launch(args);
    }
}

Answer 1

第一件事 - 你的Scene 应该包含多个元素，而不仅仅是ScrollPane。你需要一个TextField 来显示超链接的内容，这两个Controls 应该放在某种窗格上。 当鼠标经过超链接时，要处理显示内容，您需要获取所有超链接类型的节点，然后为它们添加适当的侦听器。

看看下面的代码，它做了你想要实现的（它部分基于'JavaFX WebView addHyperlinkListener' article from the 'Inspiration and Expression' blog）：

public class Main extends Application {

  @Override
  public void start(final Stage stage) {
    Scene scene = new Scene(new Group());

    final WebView browser = new WebView();
    final WebEngine webEngine = browser.getEngine();

    ScrollPane scrollPane = new ScrollPane();
    scrollPane.setContent(browser);

    TextField textField = new TextField();
    textField.setVisible(false);
    textField.setEditable(false);

    webEngine.getLoadWorker().stateProperty().addListener((observable, oldValue, newValue) -> {
      if (newValue == Worker.State.SUCCEEDED) {

        EventListener mouseOverEventListener = new EventListener() {
          @Override
          public void handleEvent(Event ev) {
            String href = ((Element) ev.getTarget()).getAttribute("href");
            textField.setText(href);
            textField.setVisible(true);
            textField.setPrefWidth(textField.getText().length() * 6); //
            System.out.println(href);
          }
        };

        EventListener mouseOutEventListener = new EventListener() {
          @Override
          public void handleEvent(Event ev) {
            textField.setVisible(false);
          }
        };

        Document document = webEngine.getDocument();
        NodeList nodeList = document.getElementsByTagName("a");
        for (int i = 0 ; i < nodeList.getLength() ; i++) {
          ((EventTarget) nodeList.item(i)).addEventListener("mouseover",mouseOverEventListener,false);
          ((EventTarget) nodeList.item(i)).addEventListener("mouseout",mouseOutEventListener,false);
        }
      }
    });

    String content = "http://java2s.com";
    webEngine.load(content);

    AnchorPane anchorPane = new AnchorPane();
    anchorPane.getChildren().add(scrollPane);
    anchorPane.getChildren().add(textField);
    AnchorPane.setBottomAnchor(textField, 0.0);
    AnchorPane.setLeftAnchor(textField, 0.0);

    scene.setRoot(anchorPane);
    stage.setScene(scene);
    stage.show();
  }

  public static void main(String[] args) {
    launch(args);
  }
}

Answer 2

我如何显示所有元素的链接的完整示例：

import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.events.Event;
import org.w3c.dom.events.EventListener;
import org.w3c.dom.events.EventTarget;
import org.w3c.dom.html.HTMLIFrameElement;
import org.w3c.dom.Element;
import javafx.application.Application;
import javafx.concurrent.Worker;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.AnchorPane;
import javafx.scene.layout.BorderPane;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Stage;

public class getWeblinksInCorner extends Application {

    EventListener mouseOverEventListener;
    EventListener mouseOutEventListener;

    @Override
    public void start(final Stage stage) {
        final WebView browser = new WebView();
        Label textField = new Label();

        final WebEngine webEngine = browser.getEngine();

        textField.setVisible(false);

        webEngine.getLoadWorker().stateProperty().addListener((observable, oldValue, newValue) -> {
            if (newValue == Worker.State.SUCCEEDED) {

                mouseOverEventListener = new EventListener() {
                    @Override
                    public void handleEvent(Event ev) {
                        String href = getNextHref((Element) ev.getTarget());
                        if (href != null && !href.isEmpty()) {
                            if (href.startsWith("/")) {
                                href = ((Element) ev.getTarget()).getBaseURI() + href;
                            }
                            textField.setText(href + "   ");
                            textField.setPrefHeight(22);
                            textField.setMaxWidth(650);
                            textField.setStyle("-fx-border-color: #C6C6C7; -fx-background-color: #F2F2F2;");
                            textField.setVisible(true);
                        }
                    }

                    private String getNextHref(Element target) {
                        while (target.getAttribute("href") == null) {
                            if (target.toString().contains("HTMLHtmlElement")) {
                                return "";
                            }
                            target = (Element) target.getParentNode();
                            if (target == null) {
                                return "";
                            }
                        }
                        return target.getAttribute("href");
                    }
                };

                mouseOutEventListener = new EventListener() {

                    @Override
                    public void handleEvent(Event ev) {
                        textField.setVisible(false);
                    }
                };

                Document document = webEngine.getDocument();
                addListener(document.getElementsByTagName("*"));
            }
        });

        String content = "http://java2s.com";
        webEngine.load(content);

        TextField tf = new TextField();
        tf.textProperty().bind(webEngine.locationProperty());
        BorderPane pane = new BorderPane();

        AnchorPane ap = new AnchorPane(browser, textField);
        AnchorPane.setBottomAnchor(browser, 0.0);
        AnchorPane.setLeftAnchor(browser, 0.0);
        AnchorPane.setTopAnchor(browser, 0.0);
        AnchorPane.setRightAnchor(browser, 0.0);
        AnchorPane.setBottomAnchor(textField, 0.0);
        AnchorPane.setLeftAnchor(textField, 0.0);
        pane.setCenter(ap);
        pane.setTop(tf);

        Scene scene = new Scene(pane);
        stage.setScene(scene);
        stage.show();
    }

    private void addListener(NodeList nodeList) {
        for (int i = 0; i < nodeList.getLength(); i++) {
            try {
                HTMLIFrameElement iFrame = ((HTMLIFrameElement) nodeList.item(i));
                addListener(iFrame.getContentDocument().getElementsByTagName("*"));
            } catch (Exception e) {
                Element el = (Element) nodeList.item(i);
                while (!el.toString().contains("HTMLHtmlElement")) {
                    el = (Element) el.getParentNode();
                    ((EventTarget) el).removeEventListener("mouseover", mouseOverEventListener, false);
                    ((EventTarget) el).removeEventListener("mouseout", mouseOutEventListener, false);
                }
                ((EventTarget) nodeList.item(i)).addEventListener("mouseover", mouseOverEventListener, false);
                ((EventTarget) nodeList.item(i)).addEventListener("mouseout", mouseOutEventListener, false);
            }
        }
    }

    public static void main(String[] args) {
        launch(args);
    }
}