Question

我有一个JavaFX WebView，并希望从webview中显示的“test.html”中调用类“JavaBridge”的方法“hello”。为什么这不起作用？我确保只有在完全呈现页面时才将“bridge”对象添加到window.object中，这可能不是问题所在。我也看不到HTML的任何问题。

以下是HTML代码（“test.html”）：

<html>
<head>
</head>
<body>
    <a href="#click" onclick="bridge.hello()">call java</a>
</body>
</html>

这是Java代码：

import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.concurrent.Worker;
import javafx.concurrent.Worker.State;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import netscape.javascript.JSObject;

public class HelloWorld extends Application {

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

  @Override
  public void start(Stage primaryStage) {

    java.net.URI uri = java.nio.file.Paths.get("test.html").toAbsolutePath().toUri();
    WebView root = new javafx.scene.web.WebView();
    root.getEngine().load(uri.toString());

    root.getEngine().
    getLoadWorker().
    stateProperty().
    addListener(new ChangeListener < State > () {
      @Override public void changed(ObservableValue ov, State oldState, State newState) {

        if (newState == Worker.State.SUCCEEDED) {
          System.out.println("READY");
          JSObject jsobj = (JSObject) root.getEngine().executeScript("window");
          jsobj.setMember("bridge", new JavaBridge());
        }

      }
    });
    primaryStage.setScene(new javafx.scene.Scene(root, 800, 600));
    primaryStage.show();
  }
}

class JavaBridge {
  public void hello() {
    System.out.println("hello");
  }
}

Answer 1

你的内部类应该在主类中。它应该是公开的。像这样：

import java.net.URL;

import javafx.application.Application;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.concurrent.Worker;
import javafx.concurrent.Worker.State;
import javafx.scene.web.WebView;
import javafx.stage.Stage;
import netscape.javascript.JSObject;

public class HelloWorld extends Application {

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

    @Override
    public void start(Stage primaryStage) {

        final URL url = getClass().getResource("test.html");

        WebView root = new javafx.scene.web.WebView();
        root.getEngine().load(url.toExternalForm());

        root.getEngine().getLoadWorker().stateProperty().addListener(new ChangeListener<State>() {
            @Override
            public void changed(ObservableValue ov, State oldState, State newState) {

                if (newState == Worker.State.SUCCEEDED) {
                    System.out.println("READY");
                    JSObject jsobj = (JSObject) root.getEngine().executeScript("window");
                    jsobj.setMember("bridge", new JavaBridge());
                }

            }
        });
        primaryStage.setScene(new javafx.scene.Scene(root, 800, 600));
        primaryStage.show();
    }

    public class JavaBridge {
        public void hello() {
            System.out.println("hello");
        }
    }
}

Answer 2

在Java 10.0.2上使用此桥接器功能时，我注意到它无法始终如一地工作。 Javascript调用并非一直有效。

经过研究，我发现了与Java Garbage Collector相关的OpenJDK错误，该错误似乎也发生在常规JDK上： https://bugs.openjdk.java.net/browse/JDK-8170085

实际上，根据https://docs.oracle.com/javase/9/docs/api/javafx/scene/web/WebEngine.html，建议将网桥存储到变量中，以避免Java GC收集对象。

在向类添加私有变量后，从JS到Java的调用一直在我的应用程序中开始工作。

Answer 3

我有同样的问题，解决此问题的唯一方法是将Bridge存储在静态变量中。这是一个使用javafx FileChooser的示例。

   active environment : base
  active env location : C:\ProgramData\Miniconda
          shell level : 1
     user config file : C:\Users\[username]\.condarc
populated config files :
        conda version : 4.5.12
  conda-build version : not installed
       python version : 3.7.0.final.0
     base environment : C:\ProgramData\Miniconda  (writable)
         channel URLs : https://repo.anaconda.com/pkgs/main/win-64
                        https://repo.anaconda.com/pkgs/main/noarch
                        https://repo.anaconda.com/pkgs/free/win-64
                        https://repo.anaconda.com/pkgs/free/noarch
                        https://repo.anaconda.com/pkgs/r/win-64
                        https://repo.anaconda.com/pkgs/r/noarch
                        https://repo.anaconda.com/pkgs/pro/win-64
                        https://repo.anaconda.com/pkgs/pro/noarch
                        https://repo.anaconda.com/pkgs/msys2/win-64
                        https://repo.anaconda.com/pkgs/msys2/noarch
        package cache : C:\ProgramData\Miniconda\pkgs
                        C:\Users\[username]\AppData\Local\conda\conda\pkgs
     envs directories : C:\ProgramData\Miniconda\envs
                        C:\Users\[username]\AppData\Local\conda\conda\envs
                        C:\Users\[username]\.conda\envs
             platform : win-64
           user-agent : conda/4.5.12 requests/2.19.1 CPython/3.7.0 Windows/10 Windows/10.0.17134
        administrator : False
           netrc file : None
         offline mode : False

来自JavaScript的JavaFX WebView up调用不起作用

3 个答案: