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()。
附上一个小例子:
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 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;
}
}
}
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.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/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>
<html xmlns="http://www.w3.org/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
*/
}
});
}
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.w3.org/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>
<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>
