PhoneGap與Android之間通信實(shí)現(xiàn)原理是本我要介紹的內(nèi)容，主要來了解PhoneGap實(shí)現(xiàn)原理。PhoneGap為移動(dòng)開發(fā)者帶來了全新的開發(fā)模式，使用javascript調(diào)用移動(dòng)設(shè)備的本地接口，這樣，你就可以在js中調(diào)用你手機(jī)的攝像頭，文件系統(tǒng)等等功能，理論上來說，你的本地應(yīng)用程序可以訪問的接口都可以通過javascript來調(diào)用了。不得不說，這樣功能實(shí)在是很強(qiáng)大。既能使用javascript，html等web技術(shù)來實(shí)現(xiàn)程序，又能通過統(tǒng)一的接口來調(diào)用本地接口。兼具了web應(yīng)用與app應(yīng)用的特點(diǎn)。

那么PhoneGap是如何實(shí)現(xiàn)javascript腳本調(diào)用本地設(shè)備的接口的呢？

相信大家都很想知道吧，那我就少點(diǎn)廢話了，一句話，通過ajax發(fā)送請(qǐng)求，實(shí)現(xiàn)腳本對(duì)設(shè)備發(fā)送消息；設(shè)備接受到消息處理后通過webView的loadUrl方法（這是Android系統(tǒng)下的瀏覽器控件對(duì)象）執(zhí)行腳本實(shí)現(xiàn)腳本的回調(diào)。

主要的代碼有下面三處：

1、

xmlhttp.open("GET", "http://127.0.0.1:"+PhoneGap.JSCallbackPort+"/"+PhoneGap.JSCallbackToken , true); 

 這是phonegap.js里面的代碼，通過ajax請(qǐng)求，發(fā)送消息給設(shè)備。
 
2、      

active = true;  
            ServerSocket waitSocket = new ServerSocket(0);  
            port = waitSocket.getLocalPort();  
            token = UUID.randomUUID().toString();  
            while(active)   
            {  
                Socket connection = waitSocket.accept();  
                BufferedReader xhrReader = new BufferedReader(new InputStreamReader(connection.getInputStream()), 40);  
                DataOutputStream output = new DataOutputStream(connection.getOutputStream());  
                String request = xhrReader.readLine();  
                String response = "";  
                if(active && request != null)  
                {  
                    if(request.contains("GET"))  
                    {  
                        String requestParts[] = request.split(" ");  
                        if(requestParts.length == 3 && requestParts[1].substring(1).equals(token))  
                        {  
                            synchronized(this)  
                            {  
                                do  
                                {  
                                    if(!empty)  
                                        break;  
                                    try  
                                    {  
                                        wait(10000L);  
                                        break;  
                                    }  
                                    catch(Exception e) { }  
                                } while(true);  
                            }  
                            if(active)  
                            {  
                                if(empty)  
                                {  
                                    response = "HTTP/1.1 404 NO DATA\r\n\r\n ";  
                                } else  
                                {  
                                    response = "HTTP/1.1 200 OK\r\n\r\n";  
                                    String js = getJavascript();  
                                    if(js != null)  
                                        response = (new StringBuilder()).append(response).append(URLEncoder.encode(js, "UTF-8")).toString();  
                                }  
                            } else  
                            {  
                                response = "HTTP/1.1 503 Service Unavailable\r\n\r\n ";  
                            }  
                        } else  
                        {  
                            response = "HTTP/1.1 403 Forbidden\r\n\r\n ";  
                        }  
                    } else  
                    {  
                        response = "HTTP/1.1 400 Bad Request\r\n\r\n ";  
                    }  
                    output.writeBytes(response);  
                    output.flush();  
                }  
                output.close();  
                xhrReader.close(); 

               
這是java代碼，監(jiān)聽javascript代碼發(fā)送過來的請(qǐng)求

3、

appView.loadUrl("javascript:PhoneGap...."); 

通過loadUrl來執(zhí)行javascript代碼。

小結(jié)：PhoneGap與Android之間通信實(shí)現(xiàn)原理的內(nèi)容介紹完了，希望通過本文的學(xué)習(xí)能對(duì)你有所幫助！