(转载) android APN切换cmwap实现

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。 

转载自 ： http://seya.iteye.com/blog/897576