/**

	 * 判断网络是否连通

	 * @param context

	 * @return

	 */

	public static boolean isNetworkConnected(Context context){

		ConnectivityManager cm = (ConnectivityManager) context.getSystemService(context.CONNECTIVITY_SERVICE);

		NetworkInfo info = cm.getActiveNetworkInfo();

		return info != null && info.isConnected();

	}

弹出对话框并设置

//如果网络连接

				if(Util.isNetworkConnected(context)){

					mMainFrameTask = new MainFrameTask();

					mMainFrameTask.execute();

				}else{

					AlertDialog.Builder builder = new Builder(context);

					builder.setTitle("设置网络");

					builder.setMessage("网络错误，请设置网络");

					builder.setPositiveButton("设置网络",new DialogInterface.OnClickListener() {

						@Override

						public void onClick(DialogInterface dialog, int which) {

							//获取系统版本号

							/* Build.VERSION_CODES

							    1 (0x00000001)           Android 1.0             BASE

							    2 (0x00000002)           Android 1.1             BASE_1_1

							    3 (0x00000003)           Android 1.5             CUPCAKE

							    4 (0x00000004)           Android 1.6             DONUT

							    5 (0x00000005)           Android 2.0             ECLAIR

							    6 (0x00000006)           Android 2.0.1          ECLAIR_0_1

							    7 (0x00000007)           Android 2.1             ECLAIR_MR1

							    8 (0x00000008)           Android 2.2             FROYO

							    9 (0x00000009)           Android 2.3             GINGERBREAD

							    10 (0x0000000a)         Android 2.3.3          GINGERBREAD_MR1

							    11 (0x0000000b)         Android 3.0             HONEYCOMB

							    12 (0x0000000c)         Android 3.1             HONEYCOMB_MR1

							    13 (0x0000000d)         Android 3.2             HONEYCOMB_MR2 */

							int currentapiVersion=android.os.Build.VERSION.SDK_INT;

							System.out.println("currentapiVersion = " + currentapiVersion);

							Intent intent;

							if(currentapiVersion < 11){

								intent = new Intent();

								intent.setClassName("com.android.settings", "com.android.settings.WirelessSettings");

							}else{

								//3.0以后

								//intent = new Intent( android.provider.Settings.ACTION_WIRELESS_SETTINGS);

								intent = new Intent( android.provider.Settings.ACTION_SETTINGS);

							}

							context.startActivity(intent);

						}

					});

					builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {

						@Override

						public void onClick(DialogInterface dialog, int which) {

						}

					});

					builder.create().show();

				}

			}

注意：3.0以前和3.0以后的设置网络方法不同。