使用javascript调用android代码

1.使用webview对象的addJavascriptInterface方法

2.addJavascriptInterface方法有两个参数，第一个参数就是我们一般会实现一个自己的类，类里面提供我们要提供给javascript访问的方法；第二个参数是访问我们在obj中声明的方法时候所用到的js对象，调用模式为window.interfaceName.方法名()或者是javascript: interfaceName.方法名() ;，如myWebView.addJavascriptInterface(new JavaScriptinterface(this), "android");

3.编写JavaScriptinterface类，如有一个函数名为showToast()的方法

4.在html中调用时的形式：javascript：android.showToast()。

JavaScriptinterface.java

 1 import android.content.Context;
 2     import android.widget.Toast;
 3     public class JavaScriptinterface {
 4         private Context mContext; 
 5         /** Instantiate the interface and set the context */
 6         public JavaScriptinterface(Context c) {
 7             mContext = c;
 8         }
 9         /** Show a toast from the web page */
10         public void showToast(String toast) {
11             Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show();
12         }
13     }

MainActivity.java

 1 import java.io.BufferedReader;
 2 import java.io.File;
 3 import java.io.InputStreamReader;
 4 import android.app.Activity;
 5 import android.content.Context;
 6 import android.os.Bundle;
 7 import android.view.KeyEvent;
 8 import android.webkit.WebView;
 9 import android.webkit.WebViewClient;
10 
11 public class MainActivity extends Activity {
12     /** Called when the activity is first created. */
13     private WebView myWebView;
14 
15     @Override
16     public void onCreate(Bundle savedInstanceState) {
17         super.onCreate(savedInstanceState);
18         setContentView(R.layout.main);
19         myWebView = (WebView) findViewById(R.id.myWebView);
20         myWebView.getSettings().setJavaScriptEnabled(true);
21         myWebView.addJavascriptInterface(new JavaScriptinterface(this),
22                 "android");
23         String htmlText = getFromAssets("test.html");
24         //把myWebView加载html
25         myWebView.loadData(htmlText, "text/html", "utf-8");
26         myWebView.setWebViewClient(new myWebViewClient());
27         
28     }
29     // 此按键监听的是返回键，能够返回到上一个网页（通过网页的hostlistery）
30     public boolean onKeyDown(int keyCode, KeyEvent event) {
31         if ((keyCode == KeyEvent.KEYCODE_BACK) && myWebView.canGoBack()) {
32             myWebView.goBack();
33             return true;
34         }
35         return super.onKeyDown(keyCode, event);
36     }
37     public String getFromAssets(String fileName) {
38         try {
39             InputStreamReader inputReader = new InputStreamReader(
40                     getResources().getAssets().open(fileName));
41             BufferedReader bufReader = new BufferedReader(inputReader);
42             String line = "";
43             String Result = "";
44             while ((line = bufReader.readLine()) != null)
45                 Result += line;
46             if (bufReader != null)
47                 bufReader.close();
48             if (inputReader != null)
49                 inputReader.close();
50             return Result;
51         } catch (Exception e) {
52             e.printStackTrace();
53         }
54         return null;
55     }
56     class myWebViewClient extends WebViewClient {
57         @Override
58         public boolean shouldOverrideUrlLoading(WebView view, String url){
59             view.loadUrl(url);
60             return true;
61         }
62     }
63 }

test.html

 1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
 2 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="zh-CN" dir="ltr">
 3 <head>
 4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
 5 
 6 <script type="text/javascript">   
 7 function showAndroidToast(toast) {       
 8     javascript:android.showToast(toast);   
 9      }
10 </script>
11 
12 </head>
13 <body>
14 <input type="button" value="Say hello"
15     onClick="showAndroidToast('Hello Android!')" />
16 </body>
17 </html>

MainActivity02.java

 1 import java.io.BufferedReader;
 2 import java.io.File;
 3 import java.io.InputStreamReader;
 4 import android.app.Activity;
 5 import android.content.Context;
 6 import android.content.Intent;
 7 import android.net.Uri;
 8 import android.os.Bundle;
 9 import android.os.Handler;
10 import android.view.KeyEvent;
11 import android.view.View;
12 import android.view.View.OnClickListener;
13 import android.webkit.WebSettings;
14 import android.webkit.WebView;
15 import android.webkit.WebViewClient;
16 import android.widget.Button;
17 
18 public class MainActivity02 extends Activity {
19     /** Called when the activity is first created. */
20     private WebView webView; 
21       private Button button; 
22       @Override 
23       public void onCreate(Bundle savedInstanceState) { 
24           super.onCreate(savedInstanceState); 
25           setContentView(R.layout.main2); 
26            
27           webView=(WebView) this.findViewById(R.id.webView); 
28           button=(Button) this.findViewById(R.id.button); 
29            
30           WebSettings setting=webView.getSettings(); 
31           //设置支持javascript 
32           setting.setJavaScriptEnabled(true); 
33             //增加接口方法,让html页面调用   
34           webView.addJavascriptInterface(new Object(){ 
35               //这里我定义了一个拨打的方法   
36               public void startPhone(String num){ 
37                   Intent intent=new Intent(); 
38                    
39                   intent.setAction(Intent.ACTION_CALL); 
40                   intent.setData(Uri.parse("tel:"+num)); 
41                   startActivity(intent); 
42               } 
43           }, "demo"); 
44           //加载页面 
45           webView.loadUrl("file:///android_asset/test2.html"); 
46            
47           button.setOnClickListener(new OnClickListener() { 
48                
49               @Override 
50               public void onClick(View v) { 
51                   // TODO Auto-generated method stub 
52                   webView.loadUrl("javascript:show('activity传过来的数据')"); //调用javascript函数
53                   /*
54                   * 通过webView.loadUrl("javascript:xxx")方式就可以调用当前网页中的名称
55                   * 为xxx的javascript方法
56                   */
57               } 
58           }); 
59 }}

test2.html

 1 <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 
 2 <html> 
 3 <head> 
 4 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 
 5 <title>Insert title here</title> 
 6 <script type="text/javascript"> 
 7      function show(content){ 
 8          document.getElementById("countent").innerHTML= 
 9              "这是我的javascript调用. 这是："+content; 
10      } 
11 </script> 
12 </head> 
13 <body> 
14   <table align="center"> 
15      <tr><td>姓名</td><td>电话</td></tr> 
16      <tr><td>小明</td><td><a  href="javascript:demo.startPhone(123)">123</a></td></tr> 
17      <tr><td>小王</td><td><a  href="javascript:demo.startPhone(456)">456</a></td></tr> 
18   </table> 
19   <p id="countent">html原始数据</p> 
20 </body> 
21 </html>

原文链接：http://www.cnblogs.com/lee0oo0/archive/2012/08/01/2617953.html