獲取有關Android設備上WiFi狀態更改的通知？

Question

我的目標是建立一個Android應用程序，記錄設備WiFi適配器正在進行的一切。例如，WiFi開啓/關閉，設備連接/移出WiFi路由器的範圍等。 我的應用應該能夠在設備開啓後立即記錄這些事件。從RECENTS清除應用程序不應該影響應用程序記錄這些事件的能力。 我已經通過BroadcastReceiver。它被綁定到應用程序的生命週期，因此一旦從RECENTS中清除應用程序就不會記錄事件。

public class MainActivity extends Activity { 
    BroadcastReceiver mybroadcastReceiver; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     mybroadcastReceiver = new WifiBroadcastReceiver(this); 
     IntentFilter intentFilter = new IntentFilter(); 
     intentFilter.addAction(WifiManager.SUPPLICANT_STATE_CHANGED_ACTION); 
     registerReceiver(mybroadcastReceiver, intentFilter); 
    } 

    @Override 
    protected void onDestroy() { 
     super.onDestroy(); 
     unregisterReceiver(mybroadcastReceiver); 
    } 
} 

public class WifiBroadcastReceiver extends BroadcastReceiver { 
    final String TAG = "WifiBroadcastReceiver"; 
    final String desiredMacAddress = "02:17:1c:96:42:fa"; 
    Activity activity; 

    WifiBroadcastReceiver(Activity activity) { 
     this.activity = activity; 
    } 

    @Override 
    public void onReceive(Context context, Intent intent) { 
     String action = intent.getAction(); 

     if (WifiManager.SUPPLICANT_STATE_CHANGED_ACTION.equals(action)) { 
      SupplicantState state = intent.getParcelableExtra(WifiManager.EXTRA_NEW_STATE); 

      if (SupplicantState.isValidState(state) && state == SupplicantState.COMPLETED) 
       checkConnectedToDesiredWifi(); 
     } 
    } 

    /** Detect you are connected to a specific network. */ 
    private void checkConnectedToDesiredWifi() { 
     WifiManager myWifiManager = (WifiManager)activity.getSystemService(Context.WIFI_SERVICE); 
     WifiInfo wifiInfo = myWifiManager.getConnectionInfo(); 

     if (wifiInfo != null) { 
      // get current router MAC address 
      String bssid = wifiInfo.getBSSID(); 

      if (desiredMacAddress.equals(bssid)) 
       Log.d(TAG, "Connected to " + bssid + " i.e., desiredMacAddress"); 
      else 
       Log.d(TAG, "Connected to " + bssid + " not " + desiredMacAddress); 
     } 
    } 
} 

Answer 1

一個解決方案可能是從不依賴於任何Activity的生命週期的服務運行BroadcastReceiver。

1）聲明在清單

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> 

1網絡狀態許可使用）創建服務類

public class WifiService extends Service { 

    private BroadcastReceiver mReceiver; 

    @Nullable 
    @Override 
    public IBinder onBind(Intent intent) { 
     // When creating the service, register a broadcast receiver 
     // to listen for network state changes 
     IntentFilter filter = new IntentFilter(); 
     filter.addAction("android.net.conn.CONNECTIVITY_CHANGE"); 

     mReceiver = new WifiReceiver(); 
     registerReceiver(mReceiver, filter); 
     return null; 
    } 

    @Override 
    public boolean onUnbind(Intent intent) { 
     // Unregister the receiver when unbinding the service 
     unregisterReceiver(mReceiver); 
     mReceiver = null; 
     return super.onUnbind(intent); 
    } 
} 

2）創建一個BroadcastReceiver

public class WifiReceiver extends BroadcastReceiver { 

    @Override 
    public void onReceive(Context context, Intent intent) { 
     ConnectivityManager manager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); 
     NetworkInfo networkInfo = manager.getActiveNetworkInfo(); 

     boolean isConnected = networkInfo != null && 
           networkInfo.isConnectedOrConnecting(); 

     if (isConnected) { 
      switch (networkInfo.getType()) { 
       case ConnectivityManager.TYPE_WIFI: 
        // Connected via wifi 
        checkConnectedToDesiredWifi(); 
        break; 

       case ConnectivityManager.TYPE_ETHERNET: 
        // Connected via ethernet 
        break; 

       case ConnectivityManager.TYPE_MOBILE: 
        // Connected via mobile data 
        break; 
      } 
     } 
    } 

    private void checkConnectedToDesiredWifi() { 
     // ... 
    } 
} 

3）聲明清單中的服務

<service android:name=".receivers.WifiService" 
      android:stopWithTask="false" 
      android:enabled="true"/>