How do you check the internet connection in android? [duplicate]

This question already has answers here: How to check internet access on Android? InetAddress never 开发者_开发知识库times out (64 answers) Closed 6 years ago.

I want to check the internet connectivity in each activity. If it is lost a message should be displayed.

Can any one guide me how to achieve this?

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Only one connection can be active at any one point. So a simpler answer is:

final ConnectivityManager conMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
final NetworkInfo activeNetwork = conMgr.getActiveNetworkInfo();
if (activeNetwork != null && activeNetwork.isConnected()) {
    // notify user you are online
} else {
    // notify user you are not online
} 

It also caters for any new type of network such as ConnectivityManager#TYPE_WIMAX

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Also make sure that you have the required permission to monitor the network state. You need to add this permission to your AndroidManifest.xml:

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

---

You can use the ConnectivityManager to check the network state.

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

if ( conMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.CONNECTED 
    || conMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.CONNECTED ) {

    // notify user you are online

}
else if ( conMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE).getState() == NetworkInfo.State.DISCONNECTED 
    || conMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI).getState() == NetworkInfo.State.DISCONNECTED) {

    // notify user you are not online
}

Note that the constants ConnectivityManager.TYPE_MOBILE and ConnectivityManager.TYPE_WIFI represent connection types and these two values are not exhaustive. See here for an exhaustive list.

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Also make sure that you have the required permission to monitor the network state. You need to add this permission to your AndroidManifest.xml:

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

---

You can do this, for various types of network status

public void  checkNetworkStatus(){

    final ConnectivityManager connMgr = (ConnectivityManager)
     this.getSystemService(Context.CONNECTIVITY_SERVICE);

     final android.net.NetworkInfo wifi =
     connMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);

     final android.net.NetworkInfo mobile =
     connMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);

     if( wifi.isAvailable() ){

     Toast.makeText(this, "Wifi" , Toast.LENGTH_LONG).show();
     }
     else if( mobile.isAvailable() ){

     Toast.makeText(this, "Mobile 3G " , Toast.LENGTH_LONG).show();
     }
     else
     {

         Toast.makeText(this, "No Network " , Toast.LENGTH_LONG).show();
     }

}

---

You can check network coverage and data availability of Mobile and wi-fi directly with

For Network coverage availability,

private boolean isNetworkAvailable()
{
 ConnectivityManager conxMgr = (ConnectivityManager)getSystemService(CONNECTIVITY_SERVICE);

 NetworkInfo mobileNwInfo = conxMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
 NetworkInfo wifiNwInfo   = conxMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);

return ((mobileNwInfo== null ? false : mobileNwInfo.isAvailable()) || (wifiNwInfo == null ? false : wifiNwInfo.isAvailable()));

}

For Data availability if network available

private boolean isDataAvailable()
{
  ConnectivityManager conxMgr = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);

 NetworkInfo mobileNwInfo = conxMgr.getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
 NetworkInfo wifiNwInfo   = conxMgr.getNetworkInfo(ConnectivityManager.TYPE_WIFI);

return ((mobileNwInfo== null? false : mobileNwInfo.isConnected() )|| (wifiNwInfo == null? false : wifiNwInfo.isConnected()));
}

---

Correction

if ( conMgr.getNetworkInfo(0).getState() == NetworkInfo.State.CONNECTED 
    ||  conMgr.getNetworkInfo(1).getState() == NetworkInfo.State.CONNECTING  ) {
   //notify user you are online
}

should be

if ( conMgr.getNetworkInfo(0).getState() == NetworkInfo.State.CONNECTED 
    ||  conMgr.getNetworkInfo(1).getState() == NetworkInfo.State.CONNECTED ) {
    //notify user you are online
}

---

Register a broadcast receiver to handle CONNECTIVITY_ACTION. See this full example. You should update a static variable 'connectionAvailable' that will be accessible everywhere and everytime through its respective getter.

Remember to declare the broadcast receiver in the manifest file:

<receiver android:name=".NetworkConnectivityReceiver" android:enabled="true">
    <intent-filter>
        <action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
    </intent-filter>
</receiver>

On the matter of 'checking in each activity', may be you would be interested in using a BaseActivity extended by your activities and managing the test of connectivity and displaying the message.

Also, note that using events (not polling from activities) will be more efficient.

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You are not using ConnectivityManager.getNetworkInfo(0).getState() and ConnectivityManager.getNetworkInfo(1).getState() properly, instead of hardcoding the values (1) and (0) use ConnectivityManager.TYPE_WIFI and ConnectivityManager.TYPE_MOBILE

---

This is a boolean check to see if you have network access. It doesn't determine what kind of network access - mobile, wifi..., it just checks to see if you're online.

boolean mobileNwInfo = false;  
ConnectivityManager conxMgr = (ConnectivityManager) getSystemService(CONNECTIVITY_SERVICE);  
try { mobileNwInfo = conxMgr.getActiveNetworkInfo().isConnected(); }  
catch (NullPointerException e) { mobileNwInfo = false; }  
if ( mobileNwInfo == false ) {
  // Your code goes here...
}