解决办法中使用到了ConnectivityManager类，但是在SDK中的ConnectivityManager类并没有提供setMobileDataEnable()、getMobileDataEnable()等方法。也看了ConnectivityManager类的源码，里面都是有这些方法的。弄了大半天，最终狠下心来，自己写个ConnectivityManager类，其中的方法和源ConnectivityManager类的方法一样，但都是空实现，编译成ConnectivityManager.class文件，然后替换android.jar包中的android.net.ConnectivityManager.class文件。然后在项目中，使用ConnectivityManager的setMobileDataEnable()方法来打开和关闭数据上网，使用getMobileDataEnable()方法获得当前连接状态，当然这需要android.permission.CHANGE_NETWORK_STATE和android.permission.ACCESS_NETWORK_STATE权限。
原解决方案来自于CSDN问答，更多解决方案见http://ask.csdn.net/questions/152
ConnectivityManager类如下：
package android.net;
import java.net.InetAddress;
public class ConnectivityManager
{
public static final String CONNECTIVITY_ACTION = "android.net.conn.CONNECTIVITY_CHANGE";
public static final String CONNECTIVITY_ACTION_IMMEDIATE = "android.net.conn.CONNECTIVITY_CHANGE_IMMEDIATE";
public static final String EXTRA_NETWORK_INFO = "networkInfo";
public static final String EXTRA_IS_FAILOVER = "isFailover";
public static final String EXTRA_OTHER_NETWORK_INFO = "otherNetwork";
public static final String EXTRA_NO_CONNECTIVITY = "noConnectivity";
public static final String EXTRA_REASON = "reason";
public static final String EXTRA_EXTRA_INFO = "extraInfo";
public static final String EXTRA_INET_CONDITION = "inetCondition";
public static final String ACTION_BACKGROUND_DATA_SETTING_CHANGED = "android.net.conn.BACKGROUND_DATA_SETTING_CHANGED";
public static final String INET_CONDITION_ACTION = "android.net.conn.INET_CONDITION_ACTION";
public static final String ACTION_TETHER_STATE_CHANGED = "android.net.conn.TETHER_STATE_CHANGED";
public static final String EXTRA_AVAILABLE_TETHER = "availableArray";
public static final String EXTRA_ACTIVE_TETHER = "activeArray";
public static final String EXTRA_ERRORED_TETHER = "erroredArray";
public static final int TYPE_NONE = -1;
public static final int TYPE_MOBILE = 0;
public static final int TYPE_WIFI = 1;
public static final int TYPE_MOBILE_MMS = 2;
public static final int TYPE_MOBILE_SUPL = 3;
public static final int TYPE_MOBILE_DUN = 4;
public static final int TYPE_MOBILE_HIPRI = 5;
public static final int TYPE_WIMAX = 6;
public static final int TYPE_BLUETOOTH = 7;
public static final int TYPE_DUMMY = 8;
public static final int TYPE_ETHERNET = 9;
public static final int TYPE_MOBILE_FOTA = 10;
public static final int TYPE_MOBILE_IMS = 11;
public static final int TYPE_MOBILE_CBS = 12;
public static final int TYPE_WIFI_P2P = 13;
public static final int MAX_RADIO_TYPE = TYPE_WIFI_P2P;
public static final int MAX_NETWORK_TYPE = TYPE_WIFI_P2P;
public static final int DEFAULT_NETWORK_PREFERENCE = TYPE_WIFI;
public static boolean isNetworkTypeValid(int networkType)