android中WebView和javascript实现数据交互实例

时间:2021-09-06 06:40:08

在看懂这篇文章之前首先要有javascript基础。

(1) js调用android的方法:

复制代码 代码如下:
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。

复制代码 代码如下:

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:
 

复制代码 代码如下:


<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();

复制代码 代码如下:
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。

复制代码 代码如下:
/**     
 * 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);                       
    }
}