连接WIFI时获取SSID

Question

I'm trying to get the SSID of the WIFI network when my android device is connected to WIFI.

I've registered a BroadcastReceiver listening for android.net.wifi.supplicant.CONNECTION_CHANGE . I get the notification when WIFI is disconnected or reconnected. Unfortunately, I can't get the network's SSID.

I'm using the following code to find the SSID:

WifiManager wifiManager = (WifiManager) context.getSystemService(context.WIFI_SERVICE);
WifiInfo wifiInfo = wifiManager.getConnectionInfo();
String ssid = wifiInfo.getSSID();

Instead of the SSID, I get the string <unknown ssid> back.

These are the permissions in the manifest (I've added ACCESS_NETWORK_STATE just to check, I don't actually need it)

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

Why does this happen? How can I get the actual SSID? Is the broadcast fired to early, before the connection is established? Is there another broadcast I should listen to? I'm only interested in WIFI connections, not 3G connections.

Update: I just checked, wifiInfo.getBSSID() returns null.

Answer 1

I listen for WifiManager.NETWORK_STATE_CHANGED_ACTION in a broadcast receiver

if (WifiManager.NETWORK_STATE_CHANGED_ACTION.equals (action)) {
        NetworkInfo netInfo = intent.getParcelableExtra (WifiManager.EXTRA_NETWORK_INFO);
        if (ConnectivityManager.TYPE_WIFI == netInfo.getType ()) {

I check for netInfo.isConnected (). Then I am able to use

WifiManager wifiManager = (WifiManager) getSystemService (Context.WIFI_SERVICE);
WifiInfo info = wifiManager.getConnectionInfo ();
String ssid  = info.getSSID();

UPDATE

From android 8.0 onwards we wont be getting SSID of the connected network unless location services are enabled and your app has the permission to access it.

Answer 2

Starting with Android 8.1 (API 27), apps must be granted the ACCESS_COARSE_LOCATION (or ACCESS_FINE_LOCATION ) permission in order to obtain results from WifiInfo.getSSID() or WifiInfo.getBSSID() . Apps that target API 29 or higher (Android 10) must be granted ACCESS_FINE_LOCATION .

This permission is also needed to obtain results from WifiManager.getConnectionInfo() and WifiManager.getScanResults() although it is not clear if this is new in 8.1 or was required previously.

Source : "BSSID/SSID can be used to deduce location, so require the same location permissions for access to these WifiInfo fields requested using WifiManager.getConnectionInfo() as for WifiManager.getScanResults()."

Answer 3

If you don't want to make Broadcast Receiver then simple try

WifiManager wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiInfo wifiInfo;

wifiInfo = wifiManager.getConnectionInfo();
if (wifiInfo.getSupplicantState() == SupplicantState.COMPLETED) {
    ssid = wifiInfo.getSSID();
}

Remember every time user disconnect or connect to new SSID or any wifi state change then you need to initialize WifiInfo ie wifiInfo = wifiManager.getConnectionInfo();

Answer 4

I found interesting solution to get SSID of currently connected Wifi AP. You simply need to use iterate WifiManager.getConfiguredNetworks() and find configuration with specific WifiInfo.getNetworkId()

My example

in Broadcast receiver with action WifiManager.NETWORK_STATE_CHANGED_ACTION I'm getting current connection state from intent

NetworkInfo nwInfo = intent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
nwInfo.getState()

If NetworkInfo.getState is equal to NetworkInfo.State.CONNECTED then i can get current WifiInfo object

WifiManager wifiManager = (WifiManager) getSystemService (Context.WIFI_SERVICE);
WifiInfo info = wifiManager.getConnectionInfo ();

And after that

public String findSSIDForWifiInfo(WifiManager manager, WifiInfo wifiInfo) {

    List<WifiConfiguration> listOfConfigurations = manager.getConfiguredNetworks();

    for (int index = 0; index < listOfConfigurations.size(); index++) {
        WifiConfiguration configuration = listOfConfigurations.get(index);
        if (configuration.networkId == wifiInfo.getNetworkId()) {
            return configuration.SSID;
        }
    }

    return null;
}

And very important thing this method doesn't require Location nor Location Permisions

In API29 Google redesigned Wifi API so this solution is outdated for Android 10.

Answer 5

In Android 8.1 it is must to turned Location on to get SSID, if not you can get connection state but not SSID

WifiManager wifiManager = (WifiManager) context.getApplicationContext().getSystemService(Context.WIFI_SERVICE);
WifiInfo wifiInfo = null;
if (wifiManager != null) 
wifiInfo = wifiManager.getConnectionInfo();
 String ssid = null;
if (wifiInfo != null) 
ssid = wifiInfo.getSSID(); /*you will get SSID <unknown ssid> if location turned off*/

Answer 6

This is a follow up to the answer given by @EricWoodruff.

You could use netInfo 's getExtraInfo() to get wifi SSID.

if (WifiManager.NETWORK_STATE_CHANGED_ACTION.equals (action)) {
    NetworkInfo netInfo = intent.getParcelableExtra (WifiManager.EXTRA_NETWORK_INFO);
    if (ConnectivityManager.TYPE_WIFI == netInfo.getType ()) {
        String ssid = info.getExtraInfo()
        Log.d(TAG, "WiFi SSID: " + ssid)
    }
}

If you are not using BroadcastReceiver check this answer to get SSID using Context

This is tested on Android Oreo 8.1.0

Answer 7

Answer In Kotlin Give Permissions

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />



 private fun getCurrentNetworkDetail() {
    val connManager =
        context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
    val networkInfo = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI)
    if (networkInfo.isConnected) {
        val wifiManager =
            context.getApplicationContext().getSystemService(Context.WIFI_SERVICE) as WifiManager
        val connectionInfo = wifiManager.connectionInfo
        if (connectionInfo != null && !TextUtils.isEmpty(connectionInfo.ssid)) {
            Log.e("ssid", connectionInfo.ssid)
        }
    }
    else{
        Log.e("ssid", "No Connection")
    }

}

Answer 8

对我来说，它只有在我设置手机本身的权限时才有效（设置 -> 应用程序权限 -> 位置始终开启）。

Answer 9

According to the explanation of the official document, on Android 10+(API 29 and higher) , declaring ACCESS_COARSE_LOCATION or ACCESS_FINE_LOCATION permissions is not enough.

1. For foreground location:

You also need to declare a foregroundServiceType of location in your Service to use foreground location.

<service
    android:name="MyNavigationService"
    android:foregroundServiceType="location" ... >
    <!-- Any inner elements would go here. -->
</service>

Or if your code running in the Activity, the activity should be visible to the user.

2. For background location:

You should declare the ACCESS_BACKGROUND_LOCATION permission in your app's manifest in order to request background location access at runtime.

Note: The Google Play Store has a location policy concerning device location, restricting background location access to apps that need it for their core functionality and meet related policy requirements.

Official document:

https://developer.android.com/training/location/permissions https://developer.android.com/guide/topics/connectivity/wifi-scan#wifi-scan-permissions

Answer 10

Check via NetworkInfo for wifi-type if it is connected. And then use wifiinfo getSSid(). You might want to remove double slashes from returnd SSID

https://play.google.com/store/apps/details?id=com.connect.freewifi

You should check out this application and developer api from http://developer.android.com/reference/android/net/wifi/WifiInfo.html

It will help you with your task.

Answer 11

Android 9 SSID showing NULL values use this code..

ConnectivityManager connManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
        if (networkInfo.isConnected()) {
            WifiManager wifiManager = (WifiManager) context.getApplicationContext().getSystemService(Context.WIFI_SERVICE);
            WifiInfo wifiInfo = wifiManager.getConnectionInfo();
            wifiInfo.getSSID();
            String name = networkInfo.getExtraInfo();
            String ssid = wifiInfo.getSSID();
            return ssid.replaceAll("^\"|\"$", "");
        }