I encountered the same problem. Since both devices know the group owner’s ip, it is already possible to send a message to the group owner. The first message you send can contain the ip address of the other device; from then on, bidirectional communication is possible. Here’s a possibility for retrieving your ip in java: … Read more
How does it work? When you visit a location-aware website in Firefox, the browser will ask you if you want to share your location. If you consent, Firefox gathers information about nearby wireless access points and your computer’s IP address, and will get an estimate of your location by sending this information to Google Location … Read more
You can use BroadcastReceiver to find out that wifi network has changed: BroadcastReceiver broadcastReceiver = new WifiBroadcastReceiver(); IntentFilter intentFilter = new IntentFilter(); intentFilter.addAction(WifiManager.SUPPLICANT_STATE_CHANGED_ACTION); context.registerReceiver(broadcastReceiver, intentFilter); The BroadcastReceiver may look like this. And to check for specific MAC address see the checkConnectedToDesiredWifi() method bellow. public class WifiBroadcastReceiver extends BroadcastReceiver { @Override public void onReceive(Context context, Intent … Read more
You need to find out which networks are available, and then pass them into CNCopyCurrentNetworkInfo. For example: CFArrayRef myArray = CNCopySupportedInterfaces(); CFDictionaryRef myDict = CNCopyCurrentNetworkInfo(CFArrayGetValueAtIndex(myArray, 0)); …and you can then use the kCNNetworkInfoKeySSID on the dictionary you’ve got back (myDict) to find out the SSID. Don’t forget to release/manage memory appropriately.
FSPL depends on two parameters: First is the frequency of radio signals；Second is the wireless transmission distance. The following formula can reflect the relationship between them. FSPL (dB) = 20log10(d) + 20log10(f) + K d = distance f = frequency K= constant that depends on the units used for d and f If d is … Read more
String ip; try { Enumeration<NetworkInterface> interfaces = NetworkInterface.getNetworkInterfaces(); while (interfaces.hasMoreElements()) { NetworkInterface iface = interfaces.nextElement(); // filters out 127.0.0.1 and inactive interfaces if (iface.isLoopback() || !iface.isUp()) continue; Enumeration<InetAddress> addresses = iface.getInetAddresses(); while(addresses.hasMoreElements()) { InetAddress addr = addresses.nextElement(); ip = addr.getHostAddress(); System.out.println(iface.getDisplayName() + ” ” + ip); } } } catch (SocketException e) { throw new … Read more
You can change system settings programatically. First you need to request the ‘WRITE_SETTINGS’ permission in your ‘AndroidManifest.xml’: <uses-permission android:name=”android.permission.WRITE_SETTINGS”/> Then you need to actually change the setting using the following code: android.provider.Settings.System.putString(getContentResolver(), android.provider.Settings.System.WIFI_USE_STATIC_IP, “0”); android.provider.Settings.System.putString(getContentResolver(), android.provider.Settings.System.WIFI_STATIC_DNS1, “192.168.0.2”); android.provider.Settings.System.putString(getContentResolver(), android.provider.Settings.System.WIFI_STATIC_DNS2, “192.168.0.3”); android.provider.Settings.System.putString(getContentResolver(), android.provider.Settings.System.WIFI_STATIC_GATEWAY, “192.168.0.1”); android.provider.Settings.System.putString(getContentResolver(), android.provider.Settings.System.WIFI_STATIC_NETMASK, “255.255.255.0”); android.provider.Settings.System.putString(getContentResolver(), android.provider.Settings.System.WIFI_STATIC_IP, “1”); The current settings can be accessed … Read more
The world has changed since this question was asked, and the answer is now the Android Open Accessory Development Kit. It won’t solve the problem for existing USB devices, but it makes it possible to create new devices that can use an Android device’s USB connection.
It does works for me: To verify network availability: private Boolean isNetworkAvailable() { ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo activeNetworkInfo = connectivityManager.getActiveNetworkInfo(); return activeNetworkInfo != null && activeNetworkInfo.isConnectedOrConnecting(); } To verify internet access: public Boolean isOnline() { try { Process p1 = java.lang.Runtime.getRuntime().exec(“ping -c 1 www.google.com”); int returnVal = p1.waitFor(); boolean reachable = (returnVal==0); return … Read more
Please refer to Android 6.0 Changes. To provide users with greater data protection, starting in this release, Android removes programmatic access to the device’s local hardware identifier for apps using the Wi-Fi and Bluetooth APIs. The WifiInfo.getMacAddress() and the BluetoothAdapter.getAddress() methods now return a constant value of 02:00:00:00:00:00. To access the hardware identifiers of nearby … Read more