转自：http://seya.iteye.com/blog/897576

有的中国移动的业务需要走CMWAP接入点才能够连接网络的，在做这类应用的时候，不可避免地需要判断当前APN, 切换APN，以及成功连接到网络后连接到服务器。 首先，获取当前的APN有两种方式，一种是从当前系统的网络连接服务获取，即通过 ConnectivityManager conManager= (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo info = conManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE); String currentAPN = info.getExtraInfo(); CurrentAPN为‘cmnet’或者’cmwap’。。。 还有一种是通过查询数据库的方式，因为我们设置的APN是存放在本地的xml中的 首先申明APN_URI: public static final Uri CURRENT_APN_URI = Uri.parse("content://telephony/carriers/preferapn"); public static final Uri APN_LIST_URI = Uri.parse("content://telephony/carriers"); 当前选中的APN记录在CURRENT_APN_URI中，而APN_LIST_URI里面是所以的APN列表。通过以下方法获取到选中的apn名字, public static String getCurrentAPNFromSetting(ContentResolver resolver) {         Cursor cursor = null;         try {             cursor = resolver.query(CURRENT_APN_URI, null, null, null, null);             String curApnId = null;             if (cursor != null && cursor.moveToFirst()) {                 curApnId = cursor.getString(cursor.getColumnIndex("apn_id"));                 String apnName1 = cursor.getString(cursor.getColumnIndex("apn"));             }             cursor.close();             //find apn name from apn list             if (curApnId != null) {                 cursor = resolver.query(APN_LIST_URI, null, " _id = ?", new String[]{curApnId}, null);                 if (cursor != null && cursor.moveToFirst()) {                     String apnName = cursor.getString(cursor.getColumnIndex("apn"));                     return apnName;                 }             }                     } catch (SQLException e) {             Debug.error(e.getMessage());         } finally {             if (cursor != null) {                 cursor.close();             }         }                 return null; } 获取到APN之后，需要判断是否是cmwap, 如果不是需要更改当前APN为cmwap. 可以通过改数据库的方式： public static int updateCurrentAPN(ContentResolver resolver, String newAPN) {         Cursor cursor = null;         try {             //get new apn id from list             cursor = resolver.query(APN_LIST_URI, null, " apn = ? and current = 1", new String[]{newAPN.toLowerCase()}, null);             String apnId = null;             if (cursor != null && cursor.moveToFirst()) {                 apnId = cursor.getString(cursor.getColumnIndex("_id"));             }             cursor.close();                         //set new apn id as chosen one             if (apnId != null) {                 ContentValues values = new ContentValues();                 values.put("apn_id", apnId);                 resolver.update(CURRENT_APN_URI, values, null, null);             } else {                 //apn id not found, return 0.                 return 0;             }         } catch (SQLException e) {             Debug.error(e.getMessage());         } finally {             if (cursor != null) {                 cursor.close();             }         }                 //update success         return 1; } 在更改数据库之后，网络并不是立刻就能连接上的，我们需要加一个网络连接的消息监听器，发现切换成cmwap之后才开始连接服务器。NetworkChangeReceiver如下： /*      * receiver for observing network connection change      */     public class NetworkChangeReceiver extends BroadcastReceiver {         public void onReceive(Context context, Intent intent) {             if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {                 NetworkInfo info = conManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);                 String apn = info.getExtraInfo();                 if ("cmwap".equals(apn)) {                     /*                      * apn change message is sent out more than once during a second, but it                      * only happens once practically.                      */                     if (mNChangeReceiver != null) {                         updateDcdContent(mManRequest);                         HwDcdCmService.this.unregisterReceiver(mNChangeReceiver);                         mNChangeReceiver = null;                     }                 }             }         }     } 切换apn总入口如下，包括了检测当前apn, 切换，注册网络监听器： /*      * change current network connection to cmwap if it's not.      */     public int forceCMWapConnection() {                 NetworkInfo info = conManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);         oldAPN = info.getExtraInfo();                 //if current apn is not cmwap, we have to switch to cmwap.         if (!"cmwap".equals(oldAPN)) {             mNChangeReceiver = new NetworkChangeReceiver();             //register receiver for wap network connection.             IntentFilter upIntentFilter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);             registerReceiver(mNChangeReceiver, upIntentFilter);              MyUtil.updateCurrentAPN(getContentResolver(), "cmwap");             return 1;         }         return 0;     } 顺便值得一提的是，使用cmwap来连接网络的时候，仅仅切换接入点还不够，需要在请求头上加上http-route.default-proxy: 10.0.172:80. 代码如下： HttpParams baseParams = new BasicHttpParams();         baseParams.setParameter("http.route.default-proxy",                 new HttpHost(“10.0.0.172”, 80));         HttpConnectionParams.setConnectionTimeout(baseParams, 30 * 1000);         HttpConnectionParams.setSoTimeout(baseParams, 45 * 1000);         // establish HttpClient         DefaultHttpClient client = new DefaultHttpClient(baseParams); 备注：笔者发现ConnectionManager提供了一个conManager.startUsingNetworkFeature(type, value)，第一个设置为ConnectivityManager.TYPE_MOBILE， 第二个为”mms”的时候，也可以进行网络的切换，不涉及到setting里面的APN值的改变。第二个参数为APN接入点中的APN类型。但是这需要framework层的支持。中移动的Ophone sdk中可以使用这种方式来切换到cmwap或internet. 但是原版的android sdk中貌似不行。