android中WebView和javascript实现数据交互实例

在看懂这篇文章之前首先要有javascript基础。

(1) js调用android的方法:

WebView wView;

wView. addJavascriptInterface (Object obj, String interfaceName);

是实例化一个对象,在html的js中调用,第二个参数是实例化对象的别名,如果要使用这个obj,则在js中使用的名字
就是interfaceName。
public class jsWebDemo extends Activity {   

    WebView wView;

    /** Called when the activity is first created. */      @Override      public void onCreate(Bundle savedInstanceState) {           super.onCreate(savedInstanceState);           setContentView(R.layout.main);            wView = (WebView)findViewById(R.id.wv1);                     WebSettings wSet = wView.getSettings();           wSet.setJavaScriptEnabled(true); 

        ProxyBridge pBridge = new ProxyBridge();           wView.addJavascriptInterface(pBridge, "AliansBridge");                    wView.loadUrl("file:///android_asset/index.html");                  }      private class ProxyBridge {     public int one () {      return 1;     }    }     }


来看一下index.html的内容:
 

<html>

  <mce:script language="javascript"><!--

  

        /* This function is invoked by the activity */   

        function wave() {   

            alert("1");   

            document.getElementById("droid").src="android_waving.png";   

            alert("2");   

        }   

    

// --></mce:script>

<body>      

<div id="output">Test page.</div>     

<a onClick="window.demo.clickOnAndroid()">  <div style="width:100px;               margin:0px auto;               padding:10px;               text-align:center;               border:2px solid #202020;" >                  <img id="droid" src="android_normal.png" mce_src="android_normal.png"/><br>                  Click me!           </div>  </a> <input type="submit" value="change to 1" onclick="document.getElementById('output').innerHTML

=AliansBridge.one()" />      </body> </html>


这里的AliansBridge即是调用的JAVA对象。
要注意的是,如果你只有一个方法需要被js调用只new一个对象就行:
ProxyBridge pBridge = new ProxyBridge();
wView.addJavascriptInterface(pBridge, "AliansBridge");
如果你需要调用好多个方法,就要把整个android程序所在的类本身实例化传递进去:
wView.addJavascriptInterface(this, "AliansBridge");
(2) android调用js的方法:wView.setWebChromeClient (WebChromeClient client)
要用到Handler更新UI,Handler mHandler = new Handler();
mWebView.setWebChromeClient(new MyWebChromeClient());                

    mWebView.addJavascriptInterface(new Object(){

    /**      

     * This is not called on the UI thread. Post a runnable to invoke      

     * loadUrl on the UI thread.      

     */        

    public void clickOnAndroid() {        

        mHandler.post(new Runnable() {         

            public void run() {         

                mWebView.loadUrl("javascript:wave()");         

            }         

        });                 

    } 

 }, "demo");

同理,在html中必须有一个名为demo的对象调用clickOnAndroid()方法。
/**      

 * Provides a hook for calling "alert" from javascript. Useful for      

 * debugging your javascript.      

 */        

final class MyWebChromeClient extends WebChromeClient {         

    @Override     

    public boolean onJsAlert(WebView view, String url, String message,      

            JsResult result) {                      

        result.confirm();       

    return super.onJsAlert(view, url, message, result);                        

    } 

}