<uses-permission android/194683.html">android/273439.html">android:name="android.permission.ACCESS_NETWORK_STATE"/><uses-permission android:name="android.permission.INTERNET"/>

public class NetWorkStateReceiver extends BroadcastReceiver {  @Override  public void onReceive(Context context, Intent intent) {    System.out.println("網絡狀態發生變化");    //檢測API是不是小于23，因為到了API23之后getNetworkInfo(int networkType)方法被棄用    if (android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.LOLLIPOP) {      //獲得ConnectivityManager對象      ConnectivityManager connMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);      //獲取ConnectivityManager對象對應的NetworkInfo對象      //獲取WIFI連接的信息      NetworkInfo wifiNetworkInfo = connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);      //獲取移動數據連接的信息      NetworkInfo dataNetworkInfo = connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);      if (wifiNetworkInfo.isConnected() && dataNetworkInfo.isConnected()) {        Toast.makeText(context, "WIFI已連接,移動數據已連接", Toast.LENGTH_SHORT).show();      } else if (wifiNetworkInfo.isConnected() && !dataNetworkInfo.isConnected()) {        Toast.makeText(context, "WIFI已連接,移動數據已斷開", Toast.LENGTH_SHORT).show();      } else if (!wifiNetworkInfo.isConnected() && dataNetworkInfo.isConnected()) {        Toast.makeText(context, "WIFI已斷開,移動數據已連接", Toast.LENGTH_SHORT).show();      } else {        Toast.makeText(context, "WIFI已斷開,移動數據已斷開", Toast.LENGTH_SHORT).show();      }//API大于23時使用下面的方式進行網絡監聽    }else {      System.out.println("API level 大于23");      //獲得ConnectivityManager對象      ConnectivityManager connMgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);      //獲取所有網絡連接的信息      Network[] networks = connMgr.getAllNetworks();      //用于存放網絡連接信息      StringBuilder sb = new StringBuilder();      //通過循環將網絡信息逐個取出來      for (int i=0; i < networks.length; i++){        //獲取ConnectivityManager對象對應的NetworkInfo對象        NetworkInfo networkInfo = connMgr.getNetworkInfo(networks[i]);        sb.append(networkInfo.getTypeName() + " connect is " + networkInfo.isConnected());      }      Toast.makeText(context, sb.toString(),Toast.LENGTH_SHORT).show();    }  }}

public class MainActivity extends AppCompatActivity {  NetWorkStateReceiver netWorkStateReceiver;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);  }  //在onResume()方法注冊  @Override  protected void onResume() {    if (netWorkStateReceiver == null) {      netWorkStateReceiver = new NetWorkStateReceiver();    }    IntentFilter filter = new IntentFilter();    filter.addAction(ConnectivityManager.CONNECTIVITY_ACTION);    registerReceiver(netWorkStateReceiver, filter);    System.out.println("注冊");    super.onResume();  }  //onPause()方法注銷  @Override  protected void onPause() {    unregisterReceiver(netWorkStateReceiver);    System.out.println("注銷");    super.onPause();  }}

<receiver android:name=".NetWorkStateReceiver">   <intent-filter> //檢測網絡變化的acton    <action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>     <category android:name="android.intent.category.DEFAULT" />   </intent-filter> </receiver>