public class NetworkDetector {    /** Network type is unknown */    public static final int NETWORK_TYPE_UNKNOWN = 0;    /** Current network is GPRS */    public static final int NETWORK_TYPE_GPRS = 1;    /** Current network is EDGE */    public static final int NETWORK_TYPE_EDGE = 2;    /** Current network is UMTS */    public static final int NETWORK_TYPE_UMTS = 3;    /** Current network is CDMA: Either IS95A or IS95B */    public static final int NETWORK_TYPE_CDMA = 4;    /** Current network is EVDO revision 0 */    public static final int NETWORK_TYPE_EVDO_0 = 5;    /** Current network is EVDO revision A */    public static final int NETWORK_TYPE_EVDO_A = 6;    /** Current network is 1xRTT */    public static final int NETWORK_TYPE_1xRTT = 7;    /** Current network is HSDPA */    public static final int NETWORK_TYPE_HSDPA = 8;    /** Current network is HSUPA */    public static final int NETWORK_TYPE_HSUPA = 9;    /** Current network is HSPA */    public static final int NETWORK_TYPE_HSPA = 10;    /** Current network is iDen */    public static final int NETWORK_TYPE_IDEN = 11;    /** Current network is EVDO revision B */    public static final int NETWORK_TYPE_EVDO_B = 12;    /** Current network is LTE */    public static final int NETWORK_TYPE_LTE = 13;    /** Current network is eHRPD */    public static final int NETWORK_TYPE_EHRPD = 14;    /** Current network is HSPA+ */    public static final int NETWORK_TYPE_HSPAP = 15;    /** Unknown network class. {@hide} */    public static final int NETWORK_CLASS_UNKNOWN = 0;    /** Class of broadly defined "2G" networks. {@hide} */    public static final int NETWORK_CLASS_2_G = 1;    /** Class of broadly defined "3G" networks. {@hide} */    public static final int NETWORK_CLASS_3_G = 2;    /** Class of broadly defined "4G" networks. {@hide} */    public static final int NETWORK_CLASS_4_G = 3;    /** Class of broadly defined "WIFI" networks. {@hide} */    public static final int NETWORK_CLASS_WIFI = 4;    /** Class of broadly defined "NONET" networks. {@hide} */    public static final int NETWORK_CLASS_NONET = 5;    /**     * 判断当前网络是否可用     *      * @param context     * @return true：可用，false:不可用；     */    public static boolean isAvailable(Context context) {        ConnectivityManager manager = (ConnectivityManager) context                .getSystemService(Context.CONNECTIVITY_SERVICE);        if (manager == null) {            return false;        }        NetworkInfo networkinfo = manager.getActiveNetworkInfo();        // NetworkInfo.isAvailable() 如果网络可用返回true，否则返回false。        if (networkinfo == null || !networkinfo.isAvailable()) {            return false;        } else {            return true;        }    }    /**     * 判断当前的网络状态     *      * @param context     * @return 0、未知， 1、2G， 2、3G， 3、4G， 4、wifi， 5、noNet；     */    public static int getNetWorkType(Context context) {        ConnectivityManager manager = (ConnectivityManager) context                .getSystemService(Context.CONNECTIVITY_SERVICE);        if (manager == null) {            return NETWORK_CLASS_NONET;        }        NetworkInfo networkinfo = manager.getActiveNetworkInfo();        if (networkinfo == null || !networkinfo.isAvailable()) {            return NETWORK_CLASS_NONET;        }        if (networkinfo.getType() == ConnectivityManager.TYPE_WIFI) {            return NETWORK_CLASS_WIFI;        } else {            return getNetworkClass(((TelephonyManager) context                    .getSystemService(Context.TELEPHONY_SERVICE))                    .getNetworkType());        }    }    public static int getNetworkClass(int networkType) {        switch (networkType) {        case NETWORK_TYPE_GPRS:        case NETWORK_TYPE_EDGE:        case NETWORK_TYPE_CDMA:        case NETWORK_TYPE_1xRTT:        case NETWORK_TYPE_IDEN:            return NETWORK_CLASS_2_G;        case NETWORK_TYPE_UMTS:        case NETWORK_TYPE_EVDO_0:        case NETWORK_TYPE_EVDO_A:        case NETWORK_TYPE_HSDPA:        case NETWORK_TYPE_HSUPA:        case NETWORK_TYPE_HSPA:        case NETWORK_TYPE_EVDO_B:        case NETWORK_TYPE_EHRPD:        case NETWORK_TYPE_HSPAP:            return NETWORK_CLASS_3_G;        case NETWORK_TYPE_LTE:            return NETWORK_CLASS_4_G;        default:            return NETWORK_CLASS_UNKNOWN;        }    }}