Develop Reference

Connection to specific WiFi if already have connection to another

I've been fighting like a fish for two days already, and I can not find a solution. I tried this code but it through time worked on Android 5(Lollipop) and didn't work at 7.1.1.(Nougat) I have another Scenario where phone loses connection and after this, it needs to return to the old Wifi.
public void setWifiConnection1(View view){
WifiManager wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
WifiConfiguration wc = new WifiConfiguration();
WifiInfo wifiInfo = wifiManager.getConnectionInfo();
wc.SSID = "\"NETWORK_NAME\"";
wc.preSharedKey = "\"PASSWORD\"";
wc.status = WifiConfiguration.Status.ENABLED;
wc.allowedProtocols.set(WifiConfiguration.Protocol.RSN);
wc.allowedProtocols.set(WifiConfiguration.Protocol.WPA);
wc.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
wc.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP40);
wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.WEP104);
wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
wc.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);
wc.priority = 999999;
wifiManager.setWifiEnabled(true);
int netId = wifiManager.addNetwork(wc);
if (netId == -1) {
netId = getExistingNetworkId(wc.SSID);
}
wifiManager.disconnect();
wifiManager.enableNetwork(netId, true);
wifiManager.reconnect();
}
private int getExistingNetworkId(String SSID) {
WifiManager wifiManager = (WifiManager) getApplicationContext().getSystemService(Context.WIFI_SERVICE);
List<WifiConfiguration> configuredNetworks = wifiManager.getConfiguredNetworks();
if (configuredNetworks != null) {
for (WifiConfiguration existingConfig : configuredNetworks) {
if (existingConfig.SSID.equals(SSID)) {
return existingConfig.networkId;
}
}
}
return -1;
}

wifiManager.setWifiEnabled(true);
You can't execute your code right after this line. You should do a wifiManager.isWifiEnabled() check and subscribe to a broadcast if it's disabled.
Next...
wifiManager.disconnect();
wifiManager.enableNetwork(netId, true);
wifiManager.reconnect();
This part is very odd: why do you disconnect ? Be aware that most of WifiManager operations are asynchronous so that's why you observe different results each time - real "disconnect" may occur after you've tried to enable your desired network.
You can always get inspiration from system API: https://android.googlesource.com/platform/frameworks/base/+/android-8.0.0_r30/wifi/java/android/net/wifi/WifiManager.java#2773
So correct sequence is:
wifiManager.addNetwork(...);
wifiManager.enableNetwork(netId, true);
wifiManager.saveConfiguration();
wifiManager.reconnect();
But if you are allowed to do so, it's more convenient to use system API directly.

Using WifiManager to connect to a wireless network (wpa2)

Trying to create a NFC tag app that stores Wifi credentials on a NFC tag then read it out. From there I take the string and use that to and put the credentials through wifimanager to connect to the wireless network. I'm pretty sure I have the code correct, but it's still not connecting. Am i missing something? The channel i'm trying to connect to is WPA2.
How i'm pulling the data for the function:
#Override
public void onClick(View v)
{
String payload = _textViewData.getText().toString();
String[] parts = payload.split("-");
String SSID = parts[0];
String Password = parts[1];
part1.setText(SSID);
part2.setText(Password);
connectToWifi(SSID, Password);
}
});
UPDATED: connect function
private void connectToWifi(final String networkSSID, final String networkPassword){
if (!wifiManager.isWifiEnabled()){
wifiManager.setWifiEnabled(true);
}
WifiConfiguration conf = new WifiConfiguration();
conf.SSID = String.format("\"%s\"", networkSSID);
conf.preSharedKey = "\""+ networkPassword +"\"";
WifiManager wifiManager = (WifiManager)this.getSystemService(Context.WIFI_SERVICE);
wifiManager.addNetwork(conf);
List<WifiConfiguration> wifiList = wifiManager.getConfiguredNetworks();
for( WifiConfiguration i : wifiList ) {
if(i.SSID != null && i.SSID.equals("\"" + networkSSID + "\"")) {
wifiManager.disconnect();
wifiManager.enableNetwork(i.networkId, true);
wifiManager.reconnect();
break;
}
}
}
UPDATE 2:
I switched my network to WPA and it worked, doesn't seem to work for WPA2, is that even possible?

For connecting WPA network you need to add passphrase like this:
conf.preSharedKey = "\""+ networkPass +"\"";
For Open network you need to do this:
conf.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE);
Then, you need to add it to Android wifi manager settings:
WifiManager wifiManager = (WifiManager)context.getSystemService(Context.WIFI_SERVICE);
wifiManager.addNetwork(conf);
after that you have to enable it.
List<WifiConfiguration> wifiList = wifiManager.getConfiguredNetworks();
for( WifiConfiguration i : wifiList ) {
if(i.SSID != null && i.SSID.equals("\"" + networkSSID + "\"")) {
wifiManager.disconnect();
wifiManager.enableNetwork(i.networkId, true);
wifiManager.status = WifiConfiguration.Status.ENABLED;
wifiManager.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);
wifiManager.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
wifiManager.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
wifiManager.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP); wifiManager.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP); wifiManager.allowedProtocols.set(WifiConfiguration.Protocol.RSN); wifiManager.allowedProtocols.set(WifiConfiguration.Protocol.WPA);
wifiManager.reconnect();
break;
}
}
Happy coding!!

Thanks #HemantParmar
With his help and a bit of googling I got it to work with WPA2:
private void connectToWifiWPA2(final String networkSSID, final String networkPassword){
WifiConfiguration conf = new WifiConfiguration();
conf.SSID = "\"" + networkSSID + "\"";
conf.preSharedKey = "\""+ networkPassword +"\"";
WifiManager wifiManager = (WifiManager)getSystemService(WIFI_SERVICE);
//if (!wifiManager.isWifiEnabled()){
// wifiManager.setWifiEnabled(true);
//}
conf.status = WifiConfiguration.Status.ENABLED;
conf.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.TKIP);
conf.allowedGroupCiphers.set(WifiConfiguration.GroupCipher.CCMP);
conf.allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK);
conf.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.TKIP);
conf.allowedPairwiseCiphers.set(WifiConfiguration.PairwiseCipher.CCMP);
conf.allowedProtocols.set(WifiConfiguration.Protocol.RSN);
int netId = wifiManager.addNetwork(conf);
wifiManager.disconnect();
wifiManager.enableNetwork(netId, true);
wifiManager.reconnect();
}

Android: How to Scan WiFi, Connect to an AP and then Establish a TCP Connection?

I am writing an Android app. In my app, I want it to scan the WiFi network, and then connect to a dedicated Access Point (AP) by checking the SSID. And then after connected to the AP, establish a TCP connection to it.
Above I have described 3 tasks in order. I know how to do each task independently, however I do not know the proper way to finish them in sequence. Examples are appreciated.
Currently my code is to start scan the WiFi network whenever the user pressed a button by:
WifiManager wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
if (wifiManager.isWifiEnabled() == false) {
wifiManager.setWifiEnabled(true);
Toast.makeText(MainActivity.this, "WiFi is enabled", Toast.LENGTH_SHORT).show();
}
wifiManager.startScan();
I used a broadcast receiver to check when the scanning finished, and then invoke a method ( ReconnectAP() ) to connect WiFi to the AP. I also used the broadcast receiver to check when it connected to the AP, then I want to execute an Async Task to establish the TCP network. However, by googling, I learn that it is a bad practice to execute async task in a broadcast receiver, because the async task can be killed by Android when the receiver finished.
private String networkSSID = "The_AP_SSID";
// In onCreate of MainActivity, register the broadcast receiver:
registerReceiver(WiFireceiver, new IntentFilter(
WifiManager.NETWORK_STATE_CHANGED_ACTION));
registerReceiver(WiFireceiver, new IntentFilter(
WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
// Implement my broadcast receiver class:
BroadcastReceiver WiFireceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
if (WifiManager.SCAN_RESULTS_AVAILABLE_ACTION.equals(action)) {
Log.d(TAG, "WiFiReceiver received broadcast, action is SCAN_RESULTS_AVAILABLE_ACTION");
Log.d(TAG, "Start to check if need to reconnect to Charger AP");
ReconnectAP();
}
if (WifiManager.NETWORK_STATE_CHANGED_ACTION.equals(action)) {
Log.d(TAG, "WiFiReceiver received broadcast, action is NETWORK_STATE_CHANGED_ACTION");
NetworkInfo netInfo = intent.getParcelableExtra(WifiManager.EXTRA_NETWORK_INFO);
// If the connection type is WiFi...
if (netInfo != null && ConnectivityManager.TYPE_WIFI == netInfo.getType()) {
// If it is connected now....
if (netInfo.isConnected()) {
Log.d(TAG, "WiFi connected");
// Get WiFi connection information, eg SSID
WifiManager wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiInfo wifiInfo = wifiManager.getConnectionInfo();
String ssid = wifiInfo.getSSID();
Log.d(TAG, "WiFi connected SSID is : " + ssid);
if(ssid.equals(networkSSID)) {
// Start async task to establish a TCP connection:
new ConnectTCPAsynTask().execute();
}
} else {
Log.d(TAG, "WiFi disconnected");
}
}
}
}
};
int ReconnectAP() {
Log.d(TAG, "In ReconnectAP( )");
wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);
WifiInfo wifiInfo = wifiManager.getConnectionInfo();
String ssid = wifiInfo.getSSID();
Log.d(TAG, "Original connected AP SSID: " + ssid);
if (!ssid.equals(networkSSID)) {
Log.d(TAG, "It is not equal to the dedicated AP SSID,
we will disconnect the current WiFi connection,
and then connect to our dedicate AP");
List<WifiConfiguration> list = wifiManager.getConfiguredNetworks();
for (WifiConfiguration i : list) {
if (i.SSID != null && i.SSID.equals("\"" + networkSSID + "\"")) {
Log.d(TAG, "Start disconnect and reconnect to " + networkSSID);
wifiManager.disconnect();
wifiManager.enableNetwork(i.networkId, true);
wifiManager.reconnect();
return 1;
}
}
Log.d(TAG,"Reach here if cannot find the target SSID");
return -1;
}
Log.d(TAG, "Reach here if we already connected to the dedicated AP");
return 0;
}

Pass a flag from the broadcast receiver back to the main activity and let the main activity handle the task.

Reconnecting to a WiFi Network after disconnecting from it Programatically

I got disconnected from a WiFi network Programatically using
WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
wifi.disconnect();
DisconnectWifi discon = new DisconnectWifi();
registerReceiver(discon, new IntentFilter(WifiManager.SUPPLICANT_STATE_CHANGED_ACTION));
public class DisconnectWifi extends BroadcastReceiver {
#Override
public void onReceive(Context c, Intent intent) {
WifiManager wifi = (WifiManager) c.getSystemService(Context.WIFI_SERVICE);
if(!intent.getParcelableExtra(WifiManager.EXTRA_NEW_STATE).toString().equals(SupplicantState.SCANNING))
wifi.disconnect();
}
}
But I am not able to reconnect to the same network again. I tried reconnecting by using:
WifiManager wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
wifi.reconnect();
but was not able to connect. How can I now reconnect to WiFi Network?
Thanks,

So the complete, simplified solution would look something like this:
WifiConfiguration wifiConfig = new WifiConfiguration();
wifiConfig.SSID = String.format("\"%s\"", ssid);
wifiConfig.preSharedKey = String.format("\"%s\"", key);
WifiManager wifiManager = (WifiManager)getSystemService(WIFI_SERVICE);
//remember id
int netId = wifiManager.addNetwork(wifiConfig);
wifiManager.disconnect();
wifiManager.enableNetwork(netId, true);
wifiManager.reconnect();
Hope it Helps You!!

Wifi manager and wifi information

i want to get some information about Wifi like SSID Name, ip address and speed, so i wrote this code
WifiManager wifiMgr = (WifiManager) getSystemService(WIFI_SERVICE);
WifiInfo wifiInfo = wifiMgr.getConnectionInfo();
int ip = wifiInfo.getIpAddress();
int speed = wifiInfo.getLinkSpeed();
speedString = Integer.toString(speed);
mac = wifiInfo.getMacAddress();
ssid = wifiInfo.getSSID();
ipAddress = Formatter.formatIpAddress(ip);
The problem is that if the WiFi is enabled but the phone is not connected to any network i show
SSID: 0x
Ip: 0.0.0.0
Speed: -1 mbps
I do not want to display this type of information so I tried it with
if(ipAddress=="0.0.0.0") {
Ip.setSummary("Not connected");
}
But don't work because i see the same information (ssid: 0x, ip: 0.0.0.0 ecc). How can i fix?

NetworkInfo networkInfo = connManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI);
if (networkInfo.isConnected()) {
WifiManager wifiMgr = (WifiManager) getSystemService(WIFI_SERVICE);
WifiInfo wifiInfo = wifiMgr.getConnectionInfo();
int ip = wifiInfo.getIpAddress();
int speed = wifiInfo.getLinkSpeed();
speedString = Integer.toString(speed);
mac = wifiInfo.getMacAddress();
ssid = wifiInfo.getSSID();
ipAddress = Formatter.formatIpAddress(ip);
}
Try this