1

我是 Java 和 JavaFX 新手。我不知道如何将变量matched从Browser实现 Web 引擎的 () 类传递回 Application ( MyScene) 类。下面列出了这两个类。我明白（我是对的吗？）它应该在变量更新之后，在页面加载之后完成。我想有两种方法可以做到这一点：通过强制MyScene类等待几秒钟，然后使用方法检索（如public String getMatched()在Browser（未列出）类中或通过通知MyScene类变量已更新。但我不知道，怎么做。有没有人有什么建议？

MyScene.java：

package mypackage;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.stage.Stage;
import javafx.concurrent.Task;

public class MyScene extends Application {
    private Scene scene;

    private static String address = "https://www.google.com";

    @Override public void start(Stage stage) {
        // create the scene
        stage.setTitle("Web View");
        Browser myBrowser = new Browser(address);

        scene = new Scene(myBrowser,750,500);
        stage.setResizable(false);
        stage.setScene(scene);
        stage.show();
    }

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

浏览器.java：

package mypackage;

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javafx.application.Platform;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.concurrent.Worker.State;
import javafx.geometry.HPos;
import javafx.geometry.VPos;
import javafx.scene.Node;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.scene.layout.Region;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;

import org.w3c.dom.Element;
import org.w3c.dom.NodeList;

class Browser extends Region {
  private String matched;
    final WebView browser = new WebView();
    final WebEngine webEngine = browser.getEngine();

    public Browser(String loadAddress) {

      String myAddress = loadAddress;
        //apply the styles
        getStyleClass().add("browser");
        // load the web page
        webEngine.load(myAddress);

        //add the web view to the scene
        getChildren().add(browser);
        webEngine.getLoadWorker().stateProperty().addListener(
            new ChangeListener<State>() {
                    public void changed(ObservableValue ov, State oldState, State newState) {
                        if (newState == State.SUCCEEDED) {

                          Pattern fbPattern = Pattern.compile(" <title id=\"([...]+)\">");
                          NodeList lst = webEngine.getDocument().getElementsByTagName("script");
                            if (lst != null && lst.getLength() > 0) {
                                  for (int i = 0; i < lst.getLength(); i++) {
                                      if (lst.item(i).getNodeType() == org.w3c.dom.Node.ELEMENT_NODE) {
                                          Element el = (Element) lst.item(i);
                                         Matcher fbMatcher = fbPattern.matcher(el.getTextContent());
                                          if (fbMatcher.find()) {
                                            matched = fbMatcher.group(1);
                                          }
                                      }
                                  }
                              }
                        }
                    }
                });
    }


    private Node createSpacer() {
        Region spacer = new Region();
        HBox.setHgrow(spacer, Priority.ALWAYS);
        return spacer;
    }

    @Override protected void layoutChildren() {
        double w = getWidth();
        double h = getHeight();
        layoutInArea(browser,0,0,w,h,0, HPos.CENTER, VPos.CENTER);
    }

    @Override protected double computePrefWidth(double height) {
        return 750;
    }


    @Override protected double computePrefHeight(double width) {
        return 500;
    }
}
4

0 回答 0