HB如何实现调用系统悬浮窗

需求：
当程序运行到后台时，收到推送信息，要弹出系统窗体显示内容。
问题：
HB如何实现以下代码呢？有没有好的实现思路？

WindowManager _winMgr=(WindowManager)getApplicationContext().getSystemService(getApplicationContext().WINDOW_SERVICE)  
_winMgr.addView(view, defaultParams);

我写了个插件，用js去调用插件，java代码如下：

if("sysView".equals(action)){  
            activity = pWebview.getActivity();  
            WindowManager wm = (WindowManager)MyApplication.context.getSystemService(MyApplication.context.WINDOW_SERVICE);  
            String url = "file:///android_asset/apps/HelloH5/www/test.html";  
            IWebview webview = SDK.createWebview(activity, url,"HelloH5",new IWebviewStateListener(){  
                @Override  
                public Object onCallBack(int pType, Object pArgs) {  
                    switch (pType) {  
                    case IWebviewStateListener.ON_WEBVIEW_READY:  

                        break;  
                    case IWebviewStateListener.ON_PAGE_STARTED:  

                        break;  
                    case IWebviewStateListener.ON_PROGRESS_CHANGED:  

                        break;  
                    case IWebviewStateListener.ON_PAGE_FINISHED:                      

                        break;  
                    }  
                    return null;  
                }  
            });  
            wm.addView((View) webview, defaultParams());  
        }

test.html这个页面并没有加载出来？