Crosswalk - 如何在XWalkExtension類中獲取android應用程序上下文？

Question

所以我按照說明在https://crosswalk-project.org/documentation/embedding_crosswalk/extensions.html上創建了Crosswalk擴展。我的問題涉及擴展XWalkExtension類。

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; 
    } 

} 

擴展XWalkExtension類時，如何獲取android應用程序上下文？因此，如果我想創建一個Toast消息，我可以傳入上下文。

Answer 1

沒有公開記錄的界面來從XWalkExtension獲取活動。您可以修改構造函數以存儲對Activity的私有引用，然後將其從實例化擴展的地方傳入。

public class ExtensionEcho extends XWalkExtension { 
    private final Activity activity; 

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

    ... 
}