如何在android中检查3g是否活跃

我正在尝试检查我的手机中的 3G 是否处于活动状态，之后我必须触发一个 Intent。 所以请有人帮助我 提前致谢：）

我最近编写的应用程序的另一个片段：

TelephonyManager telManager;    
telManager = (TelephonyManager) getApplicationContext().getSystemService(Context.TELEPHONY_SERVICE);
int cType = telManager.getNetworkType();
String cTypeString;
switch (cType) {
        case 1: cTypeString = "GPRS"; break;
        case 2: cTypeString = "EDGE"; break;
        case 3: cTypeString = "UMTS"; break;
        case 8: cTypeString = "HSDPA"; break;
        case 9: cTypeString = "HSUPA"; break;
        case 10:cTypeString = "HSPA"; break;
        default:cTypeString = "unknown"; break;
}