如何检查何时网络在Android设备上不可用？

Question

我使用android设备

我想在应用程序启动时检查当前的网络状态。

所以，我试试这个。

ConnectivityManager manager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERIVCE); 
NetworkInfo ethernet = manager.getNetworkInfo(ConnectivityManager.TYPE_ETHERNET); 
NetworkInfo wifi = manager.getNetworkInfo(ConnectivityManager.TYPE_WIFI); 

if (wifi.isConnected()) { 
    Log.d(TAG, "WIFI isConnected"); 
} else if (ethernet.isConnected()) { 
    Log.d(TAG, "Ethernet isConnected"); 
} else if (wifi.isAvaiable()) { 
    Log.d(TAG, "Wifi not connect, but wifi isAvailable"); 
} else { 
    Log.d(TAG, "not available network"); 
} 

此源码检查Wi-Fi和以太网的网络状态。

但是当无法联网时。不检查。

我的设备如果使用wifi，请在我的设备上连接无线LAN。

当我的设备上断开无线局域网。我的来源是检查wifi.isAvailable()

总之，

1. 如何检查时，网络不可用（电流源，当网络不可用检查wifi.isAvailable）

2. 当连接无线局域网和Wifi关闭，请检查wifi.isAvailable()但是当断开无线局域网和Wifi的连接时，请检查wifi.isAvailable() 如何区分这种情况。

谢谢。

Answer 1

试试这个在线或离线检查设备。

private boolean isOnline() { 
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); 
    NetworkInfo netInfo = cm.getActiveNetworkInfo(); 

    if (netInfo != null && netInfo.isConnectedOrConnecting()){ 
     return true; 
    }else return false; 
} 

Answer 2

你应该使用getActiveNetworkInfo()来检查当前活动的默认数据网络的连通性 - 无需检查特定的数据网络;无论是以太网还是Wi-Fi。

public static boolean NetAvailable(final Context context) { 
    ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); 
    NetworkInfo activeNetwork = cm.getActiveNetworkInfo(); 
    final boolean isConnected = activeNetwork != null && activeNetwork.isConnectedOrConnecting(); 
    return isConnected; 
    } 

Answer 3

试试这个功能

public boolean isNetworkAvailable(Context context) { 
     ConnectivityManager connectivity = (ConnectivityManager) context 
       .getSystemService(Context.CONNECTIVITY_SERVICE); 
     if (connectivity != null) { 
      NetworkInfo[] info = connectivity.getAllNetworkInfo(); 
      if (info != null) { 
       for (int i = 0; i < info.length; i++) { 
        if (info[i].getState() == NetworkInfo.State.CONNECTED) { 
         return true; 
        } 
       } 
      } 
     } 
     return false; 
    } 

，并检查这样

if(isNetworkAvailable(this)) 
{ 
System.out.println(""Internet Connected); 
}else 
{ 
System.out.println(""Internet Not Connected); 
} 

Answer 4

public static boolean isNetworkAvailable(Context context) { 
     ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(
       Context.CONNECTIVITY_SERVICE); 
     NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo(); 
     return activeNetworkInfo != null && activeNetworkInfo.isConnected(); 
    } 

Answer 5

对于了解网络工作状态使用这个片段

public static boolean isInternetAccess() { 
    try { 
     HttpURLConnection urlc = (HttpURLConnection) 
      (new URL("http://www.google.com") 
      .openConnection()); 
     urlc.setRequestProperty("User-Agent", "Android"); 
     urlc.setRequestProperty("Connection", "close"); 
     urlc.setConnectTimeout(1500); 
     urlc.connect(); 
     return (urlc.getResponseCode() == 200); 
    } catch (IOException e) { 
     Log.e(TAG, "Error checking internet connection", e); 
    } 

return false; 

}

如果此代码返回的失败结果意味着网络不可用，并且调用您的代码以获取可用网络。

Answer 6

您需要使用BroadcastReceiver进行连接检查。当状态改变时调用onReceive（）方法。

public BroadcastReceiver internetConnectionReciever = new BroadcastReceiver() { 

    @Override 
    public void onReceive(Context context, Intent intent) { 
     ConnectivityManager connectivityManager = (ConnectivityManager) context 
       .getSystemService(CONNECTIVITY_SERVICE); 
     NetworkInfo activeNetInfo = connectivityManager 
       .getNetworkInfo(ConnectivityManager.TYPE_MOBILE); 
     @SuppressWarnings("static-access") 
     NetworkInfo activeWIFIInfo = connectivityManager 
       .getNetworkInfo(connectivityManager.TYPE_WIFI); 

     if (activeWIFIInfo.isConnected() || activeNetInfo.isConnected()) { 

     } 
    } 
}; 

注册接收机中的onResume（）和在的onDestroy摧毁它（）

@Override 
protected void onResume() { 
    super.onResume(); 
    registerReceiver(internetConnectionReciever, new IntentFilter(
      "android.net.conn.CONNECTIVITY_CHANGE")); 

} 

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

Answer 7

public static boolean checkInternetConnection(Context context) { 
     try { 
      ConnectivityManager connec = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); 
      android.net.NetworkInfo wifi = connec.getNetworkInfo(ConnectivityManager.TYPE_WIFI); 
      android.net.NetworkInfo mobile = connec.getNetworkInfo(ConnectivityManager.TYPE_MOBILE); 
      android.net.NetworkInfo ethernet = connec.getNetworkInfo(ConnectivityManager.TYPE_ETHERNET); 

      if ((wifi != null && wifi.isConnected()) 
        || (mobile != null && mobile.isConnected()) 
        || (ethernet != null && ethernet.isConnected())) { 
       return true; 
      } 
      log("Connection", "Connection failed"); 
      return false; 
     } catch (Exception e) { 
      // TODO: handle exception 
      e.printStackTrace(); 
      return false; 
     } 
    }

使用此方法。你不需要检查wifi.isAvailable（），只需检查isConnected（）