The Android Virtual Device is connected by defualt to a wifi network called "AndroidWifi". I am working with an app that expects to be connected to a wifi network with a particular name.
How can I change the name of the wifi network from "AndroidWifi"?
Try something more pragmatic:
String getExpectedId() {
String ssid = this.getResources().getString(R.string.default_ssid);
if(Build.FINGERPRINT.contains("generic")) {ssid = "AndroidWifi";}
return ssid;
}
because you won't change the SSID (service set identifier) of the emulator's WiFi.
Despite there's adb commands alike svc wifi enable and svc wifi disable, the password for the default network likely is unknown in /data/misc/wifi/wpa_supplicant.conf; see Connecting to WiFi using adb shell. Since the emulator is rooted, one can generally configure any network alike that, while it is accessible (which the regular WiFi, which is exists in reality, obviously isn't). I think the first one approach is better, because editing emulator images isn't too portable.
AVD manager doesn't provide any ways to customize the simulated Wi-Fi access point AndroidWifi .
You may have to disable it and use another wifi simulator such as this one. It does need the Xposed framework in order to function. Here is how you can configure it.
You can modify the hostapd.conf file in your device (/data/vendor/wifi/hostapd/hostapd.conf). It will allow you to set ssid (ssid=) or even to set a password (wpa_passphrase). You will need a root access to do that.
More details at https://wiki.gentoo.org/wiki/Hostapd#WiFi_Technology
Related
I found an example on github, just jump to line 42 then you’ll see this:
ESP8266.println("AT+CWMODE=3");
AT is the command set in ESP8266 module, and AT + CWMODE=3 means initialize WiFi connection mode with both station and soft-ap modes.
p.s. The name of this example is called “ESP8266_P2P.cpp”.
The "Soft AP" part is the same as WiFi Direct. The "station" part just means that the WiFi Direct backend is the same WiFi module (as opposed to e.g. an ethernet connection).
The ESP8266 does not support the WiFi Direct specific protocols. It means that your Android phone won't see it under WiFi Direct. However, in most cases you don't need that.
this has many similar questions (google for: "no internet access detected. won't automatically reconnect." or: android force wifi connection programmatically).
i thought i had a answer here, but it stopped working after installing 6.0.1 updates (i have may 1 security patches).
seems like this is a behaviour change.
i have some 2013 nexus 7's with 6.0.1 that run a kiosk type app and want to connect programmatically to a specific wireless network that has no internet connection. each tablet has a unique static ip address of the form: 192.168.0.xx. i use the normal java socket constructors and check to see if the interface is up using: NetworkInterface.getNetworkInterfaces().
a manual connection has been made. sometimes there is a dialog that asks whether or not you want to always connect. i always check yes.
but the wifi says: "no internet access detected. won't automatically reconnect" after the router cycles power.
doing a disconnect, enable, reconnect does not work. at best it gets: ip6-localhost/::1.
has anyone had any luck using a request object, or bindProcessToNetwork?
edit: related.
edit: the problem seems to be with: CAPTIVE_PORTAL_DETECTION_ENABLED - this string seems to be defined in the source:
public static final String
CAPTIVE_PORTAL_DETECTION_ENABLED = "captive_portal_detection_enabled";
...
MOVED_TO_GLOBAL.add(Settings.Global.CAPTIVE_PORTAL_DETECTION_ENABLED);
but throws" android.provider.Settings$SettingNotFoundException: captive_portal_detection_enabled when used explicitly and is not visible to android studio.
also, doing a settings list global does not contain the constant.
edit doing a adb shell settings put global captive_portal_detection_enabled 0 does seem to work, but this can not be done in the field when the router cycles power. this value seems to persist when the tablet cycles power. and now this value shows up in a settings list global. also, using the raw string: Settings.Global.getInt(getContentResolver(),"captive_portal_detection_enabled"); now returns 0.
edit: looks like setting it requires: android.permission.WRITE_SECURE_SETTINGS, but of course this fails when put into the manifest since we are not a system app.
edit: trying to exec the shell command throws: java.lang.SecurityException, so it looks like you need to issue the command from adb :(
thanks
Could you try and set the global setting captive_portal_detection_enabled to 0 (false).
What's actually happening is that by default, everytime you connect to a wifi, the FW will test against a server (typically google) to see if it's a captive wifi (needs login). So if your wifi is not connected to google, this check will fail. After that, the device knows that wifi has no internet connection and simply will not autoconnect to it.
Setting this setting to 0, will avoid this check.
Programatically Settings.Global.putInt(getContentResolver(), Settings.Global.CAPTIVE_PORTAL_DETECTION_ENABLED, 0);
You can do it through adb for testing purposes:
adb shell settings put global captive_portal_detection_enabled 0
And retrieve it's value like this:
adb shell settings list global | grep "captive"
IMHO this is not very nice thing to do, since you are changing a setting for the user and many FWs don't provide even an advanced setting to enable/disable this by the user itself. (Google doesn't). But maybe it suits your needs.
Hope it helps!
A non-root solution which is a kind of hack tech. :P
Reboot phone, connect to the non-Internet Wifi;
Go to Settings and create a new user;
Continue, continue, and continue until you see "Checking connection";
As soon as you see "checking connection", switch off your phone;
Switch on your phone again, you will be in "Owner" user, keep it;
Toggle Wifi, and the exclamation mark should disappear quickly :)
Remove that new user or just leave it there;
I don't know why, but it works...
I need to connect 20+ android devices in a client-server network. Each client Android device will be communicating with the server Android device and vice versa. The client devices do not need to communicate with each other.
The server device would need access to internet for a brief period while connected to the clients.
My question is, can Wi-Fi P2P support that many connections reliably? And if yes, how do I go about implementing them?
Or will I have to ensure that all devices are on the same WLAN?
From experience, in a real-world deployment of an Android Wi-Fi Direct application, 20 devices should not be an issue.
Theoretically, the maximum number of devices in a Wi-Fi P2P group, where the GO is an Android device, is 254. The group owner is assigned the IP, 192.168.49.1. Clients are assigned an IP from the range, 192.168.49.2 to 192.168.49.254.
The group owner address is defined by the following in WifiP2pServiceImpl.java:
/* Is chosen as a unique address to avoid conflict with
the ranges defined in Tethering.java */
private static final String SERVER_ADDRESS = "192.168.49.1";
Determining the range for the clients is done as follows:
In WifiP2pServiceImpl.java, the startDhcpServer(String intf) method will start the DHCP server for a given interface - not a surprise. This method is called when the group has started and the device is the group owner.
Taking a closer look at this code, we can see that on the InterfaceConfiguration object, the link address is set to 192.168.49.1 and the prefix length is 24 (prefix length is the number of bits set in a subnet mask, here equivalent to 255.255.255.0) - this implies the answer, but we can dig a little further.
ifcg = mNwService.getInterfaceConfig(intf);
ifcg.setLinkAddress(new LinkAddress(NetworkUtils.numericToInetAddress(
SERVER_ADDRESS), 24));
ifcg.setInterfaceUp();
mNwService.setInterfaceConfig(intf, ifcg);
Next, the following commands will restart tethering with the DHCP range specified by the String[], tetheringDhcpRanges. The calls of mNwService (Network Management Service) methods will execute the appropriate netd commands.
ConnectivityManager cm = (ConnectivityManager) mContext.getSystemService(
Context.CONNECTIVITY_SERVICE);
String[] tetheringDhcpRanges = cm.getTetheredDhcpRanges();
if (mNwService.isTetheringStarted()) {
if (DBG) logd("Stop existing tethering and restart it");
mNwService.stopTethering();
}
mNwService.tetherInterface(intf);
mNwService.startTethering(tetheringDhcpRanges);
And cm.getTetheredDhcpRanges() is ultimately a reference to the following (ConnectivityManager.getTetheredDhcpRanges() -> ConnectivityService.getTetheredDhcpRanges() -> Tethering.getTetheredDhcpRanges()):
// USB is 192.168.42.1 and 255.255.255.0
// Wifi is 192.168.43.1 and 255.255.255.0
// BT is limited to max default of 5 connections. 192.168.44.1 to 192.168.48.1
// with 255.255.255.0
// P2P is 192.168.49.1 and 255.255.255.0
private String[] mDhcpRange;
private static final String[] DHCP_DEFAULT_RANGE = {
"192.168.42.2", "192.168.42.254", "192.168.43.2", "192.168.43.254",
"192.168.44.2", "192.168.44.254", "192.168.45.2", "192.168.45.254",
"192.168.46.2", "192.168.46.254", "192.168.47.2", "192.168.47.254",
"192.168.48.2", "192.168.48.254", "192.168.49.2", "192.168.49.254",
}
and:
mDhcpRange = context.getResources().getStringArray(
com.android.internal.R.array.config_tether_dhcp_range);
if ((mDhcpRange.length == 0) || (mDhcpRange.length % 2 ==1)) {
mDhcpRange = DHCP_DEFAULT_RANGE;
}
in com.android.server.connectivity.Tethering.
Of course, it is possible for the device manufacturer to change this code, so this is also worth considering.
For those planning to deploy applications where there will be many users, a mechanism to allow a more than one device to be GO is required. If data needs to be synchronised between devices, it is simple to simulate "churn" and have GOs only be a GO for a time period before becoming a client to another GO and synchronising any data.
The max number as far as I know is not specified, so you would need to test that out to be certain. Also there could be differences between hardware.
Anyway, the basic implementation would be rather simple. The server would call GreateGroup, so it would be the Groupowner in all cases. And then start locals service advertising. Clients then would simply look for the advertisement and once they see it, they would start connection process to the server. One the server connection is made over Wifi direct you would simply start socket communications from the client to the server (server would have listening socket on all times).
Note that connection would require user to click on the dialog showed when client tries to connect to the group owner. And if you want to get rid of this. Then you could actually use the Accesspoint created by GreateGroup, and add the access point name as well as the password to the advertising. Then your clients could actually use the accesspoint to connect (like to any Wlan accesspoint)
Note though that the Wifi Direct way, would not interfere with Wifi connections, not would it require it. But the accesspoint way would mean that any existing Wifi connection from the client would be disconnected, and the device thinks that the connection made to the server would provide normal internet connectivity.
Remember that devices don't need to be connected to a network to connect to each other. Wi-Fi Direct allows them to connect directly.
Here is a list of Wi-Fi Direct resources that you may find useful: https://groups.google.com/forum/#!topic/wi-fi-direct/uWpuOzHY6y0
I'd recommend following Android's Service Discovery Demo and try implementing it yourself. And here is the source code for the demo.
How do I get the MAC-Address of the network interface of an android device which doesn't have a Wifi-Interface (e.g. the android emulator)? WifiInfo obtained via the WifiManager returns null.
EDIT
To be more clear: I have to communicate with an existing network protocol (not designed by me) on the local network where I have to send the mac address of the communicating interface within the payload during a registration phase.
I'm going to take a leap and assume that you want this MAC address in order to establish a unique identifier for the device. Mac Addresses are not the way to do this.
There's an Android Developer Blog post titled "Identifying App Installations" which covers the topic of generating unique ID's fairly well, including the popular methods, and the pros/cons. It's definitely worth a read. Quite relevant to this post is the following quote:
It may be possible to retrieve a Mac address from a device’s WiFi or Bluetooth hardware. We do not recommend using this as a unique identifier. To start with, not all devices have WiFi. Also, if the WiFi is not turned on, the hardware may not report the Mac address.
The options available to you instead include TelephonyManager.getDeviceId(), android.os.Build.SERIAL, and Settings.Secure.ANDROID_ID, all of which are covered in more detail in the linked post.
Read /sys/class/net/[something]/address as a text file
But it's unlikely to be useful in the way you think.
See this post where I have submitted Utils.java example to provide pure-java implementations.
Utils.getMACAddress("wlan0");
Utils.getMACAddress("eth0");
Utils.getIPAddress(true); // IPv4
Utils.getIPAddress(false); // IPv6
What is the network interface you want the MAC address of? If there's no wifi, you certainly can't get the wifi device's MAC address. It represents the physical hardware and if that's not present, it simply doesn't exist.
To get wifi MAC of android device using adb:
adb shell getprop ril.wifi_macaddr
Use the following code in Java to get it programmatically:
Process p = Runtime.getRuntime.exec("adb", "shell", "getprop", "ril.wifi_macaddr")
BufferedReader br = new BufferedReader(new InputStreamReader(p.getInputStream());
String macAddress = br.readLine();
How could I programmatically set data roaming on/off in my android application ?
Apologies in advance for reopening a dead post but I have managed to achieve it by calling this executable:
su -c settings put global data_roaming0 1
Also to get the roaming setting for first SIM card:
su -c settings get global data_roaming0
If your app is signatureOrSystem/Privileged app (app resides in /system/priv-app) and your have valid android.permission.WRITE_SECURE_SETTINGS permission in system/etc/permissions. Then you can do it as below.
Enable :
Settings.Global.putInt(context.getContentResolver(), Settings.Global.DATA_ROAMING, 1)
Disable :
Settings.Global.putInt(context.getContentResolver(), Settings.Global.DATA_ROAMING, 0)
I hope that it's not possible to turn on data roaming programmatically as this would be a serious security issue from my point of view ...
Data roaming (i.e. UMTS data transfer via a foreign network) may result in a huge bill from your network provider - at least in europe.
If data roaming is currently on, then I think you can manipulate the Access Points Names in order to make it appear that a data service isn't available. See this post which also links to apndroid. You could browse their source and see the approach they have taken.
If data roaming has been set to off by the user, then this approach won't work. Though you could prompt users to turn it on as part of your install/setup process, which is the route apndroid take.
apndroid also provide an API for changing these kind of settings, which might be more convenient than reimplementing the same functionality.
On rooted devices when using su to enable data roaming, on multi sim devices the data roaming setting is sim specific.
So you need to get the sim number that is active for data calls
sim_num = settings get global multi_sim_data_call
and use this in the data_roaming + sim_num setting. EG sim_num 3
settings get global data_roaming3
if this is null then not multi sim device and use data_roaming otherwise use
settings put global data_roaming3
I was able to enable data roaming on my dual sim Motorola G8 without the need to root it via ADB. I'm posting here the procedure, because the phone has a bug that prevents data roaming from being enabled normally.
You need a computer and to install ADB installed
Enable developer mode and USB debugging in your phone
Connect the phone to the computer via USB and accept the debugging connection.
Start an "adb shell", be sure that it is correctly connected to your phone.
Issue the command
settings put global data_roaming1 1
to enable data roaming for SIM card 1, or
settings put global data_roaming2 1
to enable it for SIM 2
Note: if you do not have the USB cable, this can be done via wifi, but the pairing process is a bit complicated and version dependent.
If you do not have a computer, it may be possible to run the commands directly on the phone using a "local adb" app (there are a few on the play store), but I have not tested any.