Java Crosswalk-如何在XWalkExtension类中获得android应用程序上下文？

因此，我遵循在上创建人行横道扩展的说明。我的问题与扩展XWalkExtension类有关

package org.crosswalkproject.sample;

import org.xwalk.core.XWalkExtension;

public class ExtensionEcho extends XWalkExtension {
    private static String name = "echo";

    private static String jsapi = "var echoListener = null;" +
         "extension.setMessageListener(function(msg) {" +
         "  if (echoListener instanceof Function) {" +
         "    echoListener(msg);" + "  };" + "});" +
         "exports.echo = function (msg, callback) {" +
         "  echoListener = callback;" + "  extension.postMessage(msg);" +
         "};" + "exports.echoSync = function (msg) {" +
         "  return extension.internal.sendSyncMessage(msg);" + "};";

    public ExtensionEcho() {
        super(name, jsapi);
    }

    @Override
    public void onMessage(int instanceID, String message) {
        postMessage(instanceID, "From java: " + message);
    }

    @Override
    public String onSyncMessage(int instanceID, String message) {
        return "From java sync: " + message;
    }

}

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扩展XWalkExtension类时，如何获取android应用程序上下文？因此，如果我想创建一个Toast消息，我可以在上下文中传递。

没有公开文档化的接口来从XWalkExtension获取活动。您可以修改构造函数来存储对活动的私有引用，然后从实例化扩展的位置将其传入

public class ExtensionEcho extends XWalkExtension {
    private final Activity activity;

    public ExtensionEcho(Activity activity) {
        this.activity = activity;
    }

    ...
}