Internet connection in android emulator always displays connected state

问题

I tried in many ways to check Internet connection in my android emulator

  ConnectivityManager conMgr = (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);  

   NetworkInfo info= conMgr.getActiveNetworkInfo();  

         if(info != null || info.isConnected()) {  
              Log.v("NetworkInfo","Connected State");  
         }  
        else{  
            Log.v("NetworkInfo","Not Connected state");  
            Log.v("Reason",info.getReason());  
        }

even if i disable Internet connection in my system ,my code seems to display Connected state so i guessed this may work

 if ( conMgr.getNetworkInfo(1).getState() == NetworkInfo.State.CONNECTED
        ||  conMgr.getNetworkInfo(0).getState() == NetworkInfo.State.CONNECTED  ) {

      Log.v("Congr","Connection Present");

    }
    else if ( conMgr.getNetworkInfo(1).getState() == NetworkInfo.State.DISCONNECTED
        ||  conMgr.getNetworkInfo(0).getState() == NetworkInfo.State.DISCONNECTED) {

      Log.v("conMgr"," No Connection");

    }

but the above code also displays "Connection Present" even when i disconnect Internet cables. .Please help to find a correct way to do this .I have ACCESS_NETWORK_STATE and INTERNET permission in my manifest file

回答1:

1 Disconnecting internet cables is irrelevant. Use F8 to switch off/on internet in the emulator

2 In the first code this logic is wrong:

if(info != null || info.isConnected()) {  
              Log.v("NetworkInfo","Connected State");  
         }

It should be:

if(info != null && info.isConnected()) {  
              Log.v("NetworkInfo","Connected State");  
         }

If you use || then this is the result: a) when info is null, info.isConnected() will crash b) when info is not null, you will always show Connected State

However, even if you fix that, the code wont be completely correct (see 4)

3 In the second code, this logic is wrong:

 else if ( conMgr.getNetworkInfo(1).getState() == NetworkInfo.State.DISCONNECTED
        ||  conMgr.getNetworkInfo(0).getState() == NetworkInfo.State.DISCONNECTED) {

      Log.v("conMgr"," No Connection");

    }

should be:

 else {

      Log.v("conMgr"," No Connection");

    }

Why? Because there are more states than CONNECTED and DISCONNECTED.

However, even if you fix that, the code wont be completely correct (see 4)

4 This works on emulator and devices.

connected = (   conMgr.getActiveNetworkInfo() != null &&
            conMgr.getActiveNetworkInfo().isAvailable() &&
            conMgr.getActiveNetworkInfo().isConnected()   )

Note the use of isAvailable - without this isConnected can return TRUE when WIFI is disabled.

Hope this helps!

回答2:

Actually, this doesn't tell you if the emulator is connected to the web via the hosting PC. If you run it on a PC and the PC's wireless is turned off it still returns true as long the emulator thinks its in online state. The only way I've been able to determine for sure whether the emulator is really online is to try to fetch a page and see if it succeeds or not.

来源：https://stackoverflow.com/questions/2599633/internet-connection-in-android-emulator-always-displays-connected-state

标签

android

internet-connection