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...
Related
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
I am trying to find if I can enable and/or disable Android's built-in "Battery Saver" mode programmatically.
Any official approaches, or trickery, are welcome.
For reference, here is how to do it following Android's standard UI in 5.0:
http://www.androidcentral.com/android-50-lollipop-basics-how-get-more-life-between-charges-battery-saver
I am aware you can detect it -- that is not what I am after.
Thanks all.
You can enable/disable Battery Saver programmatically on rooted devices. You have to edit the low_power value in global table, in /data/data/com.android.providers.settings/databases/settings.db file.
If your device supports settings command, you can execute (as root):
settings put global low_power 1
to enable Energy Saver and
settings put global low_power 0
to disable it.
If it doesn't, use sqlite3 command:
sqlite3 /data/data/com.android.providers.settings/databases/settings.db "update global set value='1' where name='low_power';"
sqlite3 /data/data/com.android.providers.settings/databases/settings.db "update global set value='0' where name='low_power';"
Remember that you have to unplug your phone from PC first, otherwise system will disable Energy Saver. Use ADB over WiFi or Android Terminal (Emulator).
UPDATE:
The sqlite3 method doesn't seem to be reliable anymore.
I'm not sure if android.os.action.POWER_SAVE_MODE_CHANGED broadcast gets send. Maybe you have to send it manually, like in code from here:
private static String COMMAND_ENABLE = "settings put global low_power 1\n" +
"am broadcast -a android.os.action.POWER_SAVE_MODE_CHANGED --ez mode true\n";
private static String COMMAND_DISABLE = "settings put global low_power 0\n" +
"am broadcast -a android.os.action.POWER_SAVE_MODE_CHANGED --ez mode false\n";
Also, it's been reported that a new power_saving entry appeared in settings database, however in Android 6.0.1 I haven't managed to find it. In Android 7.1.1_r13 low_power is still used internally (e.g. here), however it may get changed in some Android release. You may want to keep checking changes in e.g. this and this file.
You cannot without rooting your phone. I am not sure why this is the case, especially where location services are required now for viewing scan results since SdkVersion 23+ .
This issue is very revealing.
https://code.google.com/p/android/issues/detail?id=185370
The best answer is application developers are being forced to crowd source network location for their google overlords. Notice, the OS itself has no problem displaying scan results without location services on.
Revealing that there is no way to turn on location services without GPS where location services are inactive. This two step shuffle is a major quality of experience issue for users. Turn location services on, then turn GPS off.
Watch this space, more lock downs on the way.
I have been doing some low-level hacking on Android.
I'm trying to enable wifi i.e. establish Internet Connectivity through terminal (adb shell). I have written a C program to achieve this by hacking into android's bionic library and libnetutils library to get things working.
Everything works fine. I'm able to acquire an IP address via dhcp request. The problem is that whenever I try to open any site for ex. google.com via browser, it does not opens. But when I enter the IP address of the site "74.125.228.66" (google.com), the page gets loaded.
I have tried several options, like modifying the dns entries in file "resolv.conf" (present in /system/etc) and in file "20-dns.conf" (in /system/etc/dhcpcd/dhcpcd-hooks).
I also tried using "setprop" call to set dns values manually for "dhcp.eth0.dns*" and "dhcp.wlan0.dns*".
But nothing seems to work. There's also an interesting behavior I noticed. If I turn on wifi manually from "settings" menu and then turn it off and then run my program, I don't face this issue anymore. Looks like it uses some settings that I could not figure out.
My guess is that this is DNS issue, but it may be something else. Let me know if anyone has faced this issue before.
Here's is what I do to enable wifi:
Enable wpa_supplicant daemon using set_prop().
Send a dhcp request to acquire IP (code from dhcpclient.c in libnetutils).
Enable dhcpcd daemon using set_prop(). (Even without this, everything works. I ran this so that IP lease gets renewed automatically. ( Although I'm not sure about this, if dhcpcd daemon would take care of lease renewal or not) ).
In order to enable WIFI on Android via command line through a C program, you'll need to do the following:
1) Enable wpa_supplicant daemon. (Make sure you have the wpa_supplicant.conf file at /data/misc/wifi with AP (access point) information in it.). wpa_supplicant internally takes care of loading the driver and then establishes connectivity to the specified networks in its configuration file based on availability and strength.
2) Issue a dhcp request. ( To fetch IP, lease, dns1, dns2 etc.)
3) Start dhcpcd daemon. (For Lease renewal)
4) Set net.dns* properties. (Without this, DNS service would not work for any application)
In order to enable daemons (wpa_supplicant and dhcpcd) and set net.dns* properties , you'll need to use Android property system (property_set() and property_get() functions). To learn more about Android Property System, follow this link:
http://rxwen.blogspot.com/2010/01/android-property-system.html
In order to use above 2 functions, you'll need to hack into bionic and core libcutils library.
Location:
/bionic/libc/bionic/system_properties.c
/system/core/libcutils/properties.c
For issuing dhcp request, you need to hack some of the implementation of libnetutils
Location:
/system/core/libnetutils/*
Disabling Wifi:
1) Unload the driver manually.
2) Stop wpa_supplicant daemon.
3) Stop dhcpcd daemon.
4) Unset net.dns* properties.
In this case, driver needs to be unloaded manually unlike loading. If this step is not done, then any of the existing connections will not be torn apart even after 2, 3, and 4. To manually unload the driver, you need to issue "DRIVER STOP" request to wpa_supplicant which will take care of interacting with kernel to unload the driver.
In order to communicate with wpa_supplicant, you'll need to hack into wpa_cli implementation to see how it works. It basically uses UNIX Domain Sockets to interact with the supplicant. You basically need to have a look at wpa_ctrl.c and wpa_cli.c
To learn more about wpa_supplicant, wpa_cli, follow below link:
http://hostap.epitest.fi/wpa_supplicant/devel/
All above that I explained to you is done in Android at HAL layer.
Location:
/hardware/libhardware_legacy/wifi/wifi.c
So, basically whenever you toggle wifi switch from settings menu, control passes from wifi_app code to wifi_frameworks layer (WifiManager and WifiServices) which passes control to wifi.c (HAL layer) through JNI implementation (WifiNative).
A good starting point would be to look at wifi.c if you want to know things that are done at low level to enable wifi.
PS - All above is what I learned after several attempts trying to figure out stuff on my own. There are no documents or blogs (atleast I didn't find any!) that would specify what needs to be done and order of events that should be followed to enable/disable WIFI. So, it may be possible you might find a better way of doing things. This worked for me, something else might work for you!
I have a problem that has been nagging me to an extreme extend in the past few days. I would like to write an Android sh script that does the following (to help me sync music, pics etc.):
1) Turn on wifi (wifi is off by default to save power)
2) Check if my wifi connection is in range (lets call it myWifi)
3) If myWifi is not in range, disable wifi, if it is in range, connect and start some synch software
Now, to enable / disable wifi, I use the following command, which requires root:
svc wifi enable / disable
To scan for avaible wifi connections, I use the following command:
iwlist eth0 scan
The strage thing is, that iwlist eth0 scan will only work if I am NOT logged in as root (I am very curious to why this is the case, if anyone knows anything?), running it while root will return:
eth0: Interface doesn't support scanning : Invalid argument
but running it while not logged in as root, will give me the info I need. I have tried different approaches to get around this problem. The most obvious one is logging in as the standard user in the Android system right before invoking the iwlist command:
su -c app_1
However, any command that involves su will return permission denied even when invoking it as root, and since sudo does not exist in Android, I feel pretty lost here. I did also try a workaround involving splitting the script into two parts, and trying to run the first as root and the second as non root (the default user in Android i app_1), but this will only delay the problem...
If anyone has an answer to how to either get around this user problem, or how to use iwlist eth0 scan (or another command that does the same) while logged in as root, I would be very gratefull.
Thank you.
According to man iwlist normal users can only see some left-over scanning results. To initiate a new scan as root you first need to start up your interface (after starting wifi):
ifconfig wlan0 up
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.