Android之如何使用javascript调用android代码使用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()。 import android.content.Context; import android.widget.Toast; public class JavaScriptinterface { private Context mContext; /** Instantiate the interface and set the context */ public JavaScriptinterface(Context c) { mContext = c; } /** Show a toast from the web page */ public void showToast(String toast) { Toast.makeText(mContext, toast, Toast.LENGTH_SHORT).show(); } } import java.io.BufferedReader; import java.io.File; import java.io.InputStreamReader; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.view.KeyEvent; import android.webkit.WebView; import android.webkit.WebViewClient; public class MainActivity extends Activity { /** Called when the activity is first created. */ private WebView myWebView; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); myWebView = (WebView) findViewById(R.id.myWebView); myWebView.getSettings().setJavaScriptEnabled(true); myWebView.addJavascriptInterface(new JavaScriptinterface(this), "android"); String htmlText = getFromAssets("test.html"); //把myWebView加载html myWebView.loadData(htmlText, "text/html", "utf-8"); myWebView.setWebViewClient(new myWebViewClient()); } // 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) public boolean onKeyDown(int keyCode, KeyEvent event) { if ((keyCode == KeyEvent.KEYCODE_BACK) && myWebView.canGoBack()) { myWebView.goBack(); return true; } return super.onKeyDown(keyCode, event); } public String getFromAssets(String fileName) { try { InputStreamReader inputReader = new InputStreamReader( getResources().getAssets().open(fileName)); BufferedReader bufReader = new BufferedReader(inputReader); String line = ""; String Result = ""; while ((line = bufReader.readLine()) != null) Result += line; if (bufReader != null) bufReader.close(); if (inputReader != null) inputReader.close(); return Result; } catch (Exception e) { e.printStackTrace(); } return null; } class myWebViewClient extends WebViewClient { @Override public boolean shouldOverrideUrlLoading(WebView view, String url) { // TODO Auto-generated method stub view.loadUrl(url); return true; } } } <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www./TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www./1999/xhtml" xml:lang="zh-CN" dir="ltr"> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <script type="text/javascript"> function showAndroidToast(toast) { javascript:android.showToast(toast); } </script> </head> <body> <input type="button" value="Say hello" onClick="showAndroidToast('Hello Android!')" /> </body> </html> android的应用程序中,可以直接调用WebView 中的javascript 代码: import java.io.BufferedReader; import java.io.File; import java.io.InputStreamReader; import android.app.Activity; import android.content.Context; import android.content.Intent; import android.net.Uri; import android.os.Bundle; import android.os.Handler; import android.view.KeyEvent; import android.view.View; import android.view.View.OnClickListener; import android.webkit.WebSettings; import android.webkit.WebView; import android.webkit.WebViewClient; import android.widget.Button; public class MainActivity02 extends Activity { /** Called when the activity is first created. */ private WebView webView; private Button button; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main2); webView=(WebView) this.findViewById(R.id.webView); button=(Button) this.findViewById(R.id.button); WebSettings setting=webView.getSettings(); //设置支持javascript setting.setJavaScriptEnabled(true); //增加接口方法,让html页面调用 webView.addJavascriptInterface(new Object(){ //这里我定义了一个拨打的方法 public void startPhone(String num){ Intent intent=new Intent(); intent.setAction(Intent.ACTION_CALL); intent.setData(Uri.parse("tel:"+num)); startActivity(intent); } }, "demo"); //加载页面 webView.loadUrl("file:///android_asset/test2.html"); button.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub webView.loadUrl("javascript:show('activity传过来的数据')"); //调用javascript函数 /* * 通过webView.loadUrl("javascript:xxx")方式就可以调用当前网页中的名称 * 为xxx的javascript方法 */ } }); } } <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www./TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Insert title here</title> <script type="text/javascript"> function show(content){ document.getElementById("countent").innerHTML= "这是我的javascript调用. 这是:"+content; } </script> </head> <body> <table align="center"> <tr><td>姓名</td><td>电话</td></tr> <tr><td>小明</td><td><a href="javascript:demo.startPhone(123)">123</a></td></tr> <tr><td>小王</td><td><a href="javascript:demo.startPhone(456)">456</a></td></tr> </table> <p id="countent">html原始数据</p> </body> </html> 分类: android讲义
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