在网上搜索开启wifi后自动关闭移动数据，但搜到的都是如何打开关闭wifi/3g，如何监听wifi/3g的状态，没有完整的。于是自己整了一天，终于搞定了。

首先在服务中注册动态广播，在OnReceive方法中，获得网络连接服务，然后创建NetworkInfo对象获得网络连接类型，用Boolean类型的isWifiConnected做判断。当wifi在一定时间内没有连上，就关闭wifi并打开3g网，当wifi连上了就关闭3g网。

mReceiver = new BroadcastReceiver() {

@Override

public void onReceive(Context context, Intent intent) {

boolean isWifiConnected = false;

boolean isMobileConnected = false;

ConnectivityManager connMgr = (ConnectivityManager) context

.getSystemService(Context.CONNECTIVITY_SERVICE);

NetworkInfo networkInfo = connMgr

.getNetworkInfo(ConnectivityManager.TYPE_WIFI);

isWifiConnected = networkInfo.isConnected();

//判断wifi是否开启

if (isWifiConnected) {

Toast.makeText(context, "wifi is on", 0).show();

Log.i("NetLisService", "wifi is "+isWifiConnected);

//wifi连接上就关闭3g网

NetLisService.this.setMobileDataStatus(NetLisService.this,false);

}else{

Toast.makeText(context, "wifi is off", 0).show();

Log.i("NetLisService", "wifi is "+isWifiConnected);

new Thread(){

public void run() {

try {

//当wifi断开十秒没连接上就关闭wifi

Thread.sleep(10000);

WifiManager wifiManager = (WifiManager) getSystemService(WIFI_SERVICE);

//关闭wifi

wifiManager.setWifiEnabled(false);

//开启3g

NetLisService.this.setMobileDataStatus(NetLisService.this,true);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

};

}.start();

}

//网络连接改为3g模式

networkInfo = connMgr

.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

isMobileConnected = networkInfo.isConnected();

//判断3g是否开启

if (isMobileConnected) {

Toast.makeText(context, "3g is on", 0).show();

Log.i("NetLisService", "3g is "+isMobileConnected);

}else{

Toast.makeText(context, "3g is off", 0).show();

Log.i("NetLisService", "3g is "+isMobileConnected);

}

}

};

IntentFilter filter = new IntentFilter();

//添加过滤action

filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);

registerReceiver(mReceiver, filter);

这是网上扒下来的开关移动数据的方法

public void setMobileDataStatus(Context context , boolean enabled) {

ConnectivityManager conMgr = (ConnectivityManager) this

.getSystemService(Context.CONNECTIVITY_SERVICE);

// ConnectivityManager类

Class> conMgrClass = null;

// ConnectivityManager类中的字段

Field iConMgrField = null;

// IConnectivityManager类的引用

Object iConMgr = null;

// IConnectivityManager类

Class> iConMgrClass = null;

// setMobileDataEnabled方法

Method setMobileDataEnabledMethod = null;

try {

// 取得ConnectivityManager类

conMgrClass = Class.forName(conMgr.getClass().getName());

// 取得ConnectivityManager类中的对象Mservice

iConMgrField = conMgrClass.getDeclaredField("mService");

// 设置mService可访问

iConMgrField.setAccessible(true);

// 取得mService的实例化类IConnectivityManager

iConMgr = iConMgrField.get(conMgr);

// 取得IConnectivityManager类

iConMgrClass = Class.forName(iConMgr.getClass().getName());

// 取得IConnectivityManager类中的setMobileDataEnabled(boolean)方法

setMobileDataEnabledMethod = iConMgrClass.getDeclaredMethod(

"setMobileDataEnabled", Boolean.TYPE);

// 设置setMobileDataEnabled方法是否可访问

setMobileDataEnabledMethod.setAccessible(true);

// 调用setMobileDataEnabled方法

setMobileDataEnabledMethod.invoke(iConMgr, enabled);

} catch (ClassNotFoundException e) {

e.printStackTrace();

} catch (NoSuchFieldException e) {

e.printStackTrace();

} catch (SecurityException e) {

e.printStackTrace();

} catch (NoSuchMethodException e) {

e.printStackTrace();

} catch (IllegalArgumentException e) {

e.printStackTrace();

} catch (IllegalAccessException e) {

e.printStackTrace();

} catch (InvocationTargetException e) {

e.printStackTrace();

}

}