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Always-on VPN switch on programmatically android

Can Always-on VPN switch be on programmatically?
I have added the device admin permission. After that i have set always on in with device admin
mDPM = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
mDeviceAdminSample = new ComponentName(this, DeviceAdminReceiver.class);
isAdminApp = mDPM.isAdminActive(mDeviceAdminSample);
if (isAdminApp) {
try {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
mDPM.setAlwaysOnVpnPackage(mDeviceAdminSample,"", true);
}
} catch (PackageManager.NameNotFoundException namenotfoundexception) {
namenotfoundexception.printStackTrace();
} catch (Exception ex) {
}
}
but it's not enabling the always on.
i have added package name insted of
mDPM.setAlwaysOnVpnPackage(mDeviceAdminSample,"my.app.package.name", true);
but still not enabling the switch.
Then what this code is doing?
How can i enable it programatically?
I want this to be like below image

According to docs, setAlwaysOnVpnPackage can only be used by the profile owner (usually the MDM client on work profile) or device owner (for fully managed devices):
Called by a device or profile owner to configure an always-on VPN connection through a specific application for the current user. This connection is automatically granted and persisted after a reboot.
As a personal profile user - I don't want my VPN to decide for itself when to connect (set always on programmatically will immediately connect the VPN, if implemented correctly).
As a work profile user (wearing the hat of an employee), it's not my decision, but my organization's (via the profile owner app).
So, all in all, this behavior makes sense.
Update:
Instead implementing MDM, which could take a lot of work, you can clone, build and debug Google's Test DPC app, which have everything you need to test toggling always-on VPN programmatically.
It also have million other things, which you don't need so be sure to ignore the rest :)
I haven't looked at their code, but I suggest searching for usages of setAlwaysOnVpnPackage function.
Google's Test DPC app:
Link to Play Store
Link to GitHub repo (to build & debug it yourself)

Java usb4java reading from usb device on windows 10 platform

I am trying to read a message from RFID reader connected via USB to windows 10pro machine with usb4java library.
I have managed to claim the interface, opened pipe and registered listener for the data, however the listener is never triggered. The reader acts as keyboard and whatever it reads ends up in active application, such as IDE i have open, instead of in listener.
UsbInterface usbInterface = activeInteface(device);
// there is only one endpoint in the list
UsbEndpoint endpoint = (UsbEndpoint)usbInterface.getUsbEndpoints().get(0);
UsbPipe pipe = endpoint.getUsbPipe();
try {
usbInterface.claim();
// true
System.out.println("claimed usb interface: " + usbInterface.isClaimed());
pipe.open();
// true
System.out.println("pipe open: " + pipe.isOpen());
pipe.addUsbPipeListener(new MessageListener());
// true
System.out.println("pipe active: " + pipe.isActive());
// keep main thread alive, async call should be done from another thread i guess
Thread.sleep(15000);
}
catch (Exception any) {System.out.println(any);}
}
And the listener:
private static class MessageListener implements UsbPipeListener {
#Override
public void errorEventOccurred(UsbPipeErrorEvent event) {
System.out.println(event.toString() + " , " +event.getUsbException());
}
#Override
public void dataEventOccurred(UsbPipeDataEvent event) {
// this code block never triggers
System.out.println("listener ...);
int actualLength = event.getActualLength();
System.out.println("length: " + actualLength);
byte[] data = event.getData();
System.out.println("data length " + data.length);
}
}
i have also tried synchronous read instead of asynchronous in the block above, like this:
byte[] buffer = new data[8];
// this fails on its own, don't even need to read something with RFID reader
int received = pipe.syncSubmit(buffer);
fails with:
USB error1: Transfer error on interrupt endpoint: Input/Output error
There is some windows specific property that library supports: org.usb4java.javax.useUSBDK = true
but this fails when i try to set it with an exception.
I have 0 experience with USB devices so not sure how to proceed from here. Is there something wrong with the code, do i need USBDK or device does not support libUSB driver ? Sadly this is not my device and i don't have access to documentation of the device so cannot be sure if it is device driver issue.

I know that this is 2 years old, but i've had similar issue and this was one of the first questions that i ran into looking for solution, which took me hours.
So, basically, windows doesn't let to read/write keyboard devices directly, to do so, you have to override it's driver (That's why you're getting Input/Output error, and it's written in the hid4java's FAQ).
First way to override device driver is described in libusb wiki.
As far as i know you would have to install a new driver every time you connect the device to a new USB port, which is why i recommend you to read further.
Second way is what you've already mentioned, which is using UsbDk (Usb Drivers Development Kit for Windows). It makes the device accessible for you by detaching the kernel driver and reattaching it back after you're done playing with it.
In order to use it, you need to do two things:
Set the org.usb4java.javax.useUSBDK = true in you javax.usb.properties file as stated in the manual (this can also be done manually in low-level usb4java, see OPTION_USE_USBDK and setOption(Context, int)).
Download and install UsbDk on your system (simplest way is to download x64 or x86 version msi installer which has GUI and is fully automated), which is sadly not in the manual (maybe it's obvious for some people, but took me amount of time that i am not proud of to realize).
Im guessing that the lack of second step is why OP has been getting an exception.
Hope that this will help someone, knowing all this two days ago would save me a lot of headache.

RFID readers operate in keyboard emulation mode by default.
You can normally get a tool from the manufacturer's website to configure the RFID reader.
This will allow you to change the reader to HID mode.
This should resolve your issues.
Sorry for the late response but I hope it helps others.

How to download files in background regardless of Application state?

This has been asked a couple of times on Unity Questions, but never answered.
All I need to do is creare an Android pluugin which downloads few files from given urls and show a downloading progress in notification panel. Downloading should continue even if my Unity application is out of focus.
(source: cuelogic.com)
Here is a peice of code that I have right now:
void DownloadFiles(string[] urls)
{
foreach(var url in urls)
{
StartCoroutine(DownloadFile_CR(url));
}
}
IEnumerator DownloadFile_CR(string url)
{
WWW www = new WWW(url);
while(!www.isDone)
{
yield return null;
}
if(www.error == null)
{
//file downloaded. do something...
}
}
These are some texture files. So How do I get the texture result back from native android code?
Any king of help is appreciated.

I had the same problem. At first, I used a service that worked in the background and downloaded the files I needed, including calculating progress and on complete events.
Then, I made my plugin a little more simple and easy to use. You make an instance of a Java object, providing it with the GameObject name and method name for the responses. I used json to serialize and deserialize java and C# objects, because only strings can be passed between Unity's MonoBehaviour objects and java objects.
Here is how the downnload looks in the android plugin:
Uri Download_Uri = Uri.parse(url);
DownloadManager.Request request = new DownloadManager.Request(Download_Uri);
//Restrict the types of networks over which this download may proceed.
request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI | DownloadManager.Request.NETWORK_MOBILE);
//Set whether this download may proceed over a roaming connection.
request.setAllowedOverRoaming(true);
//Set the local destination for the downloaded file to a path within the application's external files directory
String[] split = url.split("/");
request.setDestinationInExternalFilesDir(activity, null, split[split.length-1]);
//Set the title of this download, to be displayed in notifications (if enabled).
request.setTitle("Downloading " + title);
//Set a description of this download, to be displayed in notifications (if enabled)
request.setDescription("Downloading " + name);
request.setVisibleInDownloadsUi(false);
//Enqueue a new download and get the reference Id
long downloadReference = downloadManager.enqueue(request);
Then you could send back to unity the reference Id so you can get the progress and check if a file is still downloading once your app is been restarted (use SharedPreferences \ PlayerPrefs to store them)

If you want it to continue even when unity is not in focus then you cannot do it in C# in Unity with the WWW class.
If i wanted to do this i would probably write a native Android plugin that starts a download service.
From the official google docs:
A Service is an application component that can perform long-running
operations in the background, and it does not provide a user
interface. Another application component can start a service, and it
continues to run in the background even if the user switches to
another application.
Services are not that complex, you start them with Intents just as you would an activity and there are lots of examples online for this type of service.
Here is the official Android documentation regarding services: https://developer.android.com/guide/components/services.html

ELM327 returns `?` when trying to use it with ODB Java API

I'm trying to use ODB Java API (this library) to get the data from ELM327 via Bluetooth from my car, but in returns ? on every request, and library raises MisunderstoodException
Here is my code:
socket = device.createInsecureRfcommSocketToServiceRecord(uuid);
socket.connect();
final CustomRPMCommand engineRpmCommand = new CustomRPMCommand();
final SpeedObdCommand speedObdCommand = new SpeedObdCommand();
while (!Thread.currentThread().isInterrupted()) {
engineRpmCommand.run(socket.getInputStream(), socket.getOutputStream());
speedObdCommand.run(socket.getInputStream(), socket.getOutputStream());
runOnUiThread(new Runnable() {
#Override
public void run() {
speedometerGauge.setSpeed(engineRpmCommand.getRPM(), true);
rpmGauge.setSpeed(speedObdCommand.getMetricSpeed(), true);
}
});
}
What's wrong?

I also used the same library for the first steps into trying out OBD, so I can say at least at the time I used it, it worked fine.
From my experience however, getting ? back can sometimes happen with cheap Bluetooth devices (maybe even with expensive ones? never had one). I guess this happens, if some bits are lost during the transmission, because then command will be misunderstood.
What I did to circumvent this problem is setting up a process where I sent all AT commands up to 10 times until I get the desired response of OK (except for ATZ, which will respond with ELM327). As for value requests like RPM etc. I usually just throw away the erroneous values.
That's the short answer, but since such problems with the devices can annoy a lot, I will guide you into debugging the whole process...
Setting up a terminal on windows
First of all to test the functionality of the ELM device, you can send commands to the serial interface directly. On windows, this is possible using for example TeraTerm and then setting up new Bluetooth connection on your windows as a COM device (search for Bluetooth in start -> search box and then choose Change Bluetooth settings or similar). From there, go to COM connections and then add a new one Outgoing for the Bluetooth OBDII device. Wait a bit for windows to calculate the new COM port number, you will need it.
If you cannot find OBDII in the dropdown box, you have to bond your PC with your Bluetooth device first. This can be done via devices and printers, there you should see the OBDII device, so you only have to connect it (PIN usually is 1234).
If you're on Linux, it might be somewhat easier, but I haven't done it :)
Sending some commands via terminal
Once you have your Bluetooth connection and TeraTerm installed, you can start TeraTerm and connect to the adapter. Choose Serial and then the port you just set up. Ensure, that no other device is connected to the OBD adapter (also not your phone). Only one device can be connected at a time.
If connection was successful, you should be able to type letters. Usually, in default settings you should be able to see the letters you type (Echo mode on), but since this is not certain, just type ATZ and hit <Enter>. The ELM should respond with "ELM327" in the same line now (which for me usually results in odd display if echo mode was on, but you should get any response).
From terminal I usually send these commands in order:
ATZ
E1
L1
010c
This will trigger:
Reset of the OBD device
Make sure that echo is on, so I see what I am typing
Make sure Line feed is on, so we get responses in the next line
Request RPM from the vehicle
Between each command I'll check what is the reply of the device. For all AT commands (1., 2. and 3.) it must be OK. If I get back ?, which can happen, I will repeat the command another time. You will see that in such a case the device indeed did not follow the instructions, e.g. did not set line feed on if it was off. So we really have to send it again.
In programming mode on the other hand, we will set e0 and l0 (echo mode off and line feed off), because we do not want to get sent back what we already sent out.

admob test ads appearing

I released my Android app two days ago, using admob advertising. I used my personal phone as the test phone, but took out the test mode code before releasing it. My admob status is active and I get requests and impressions on the report, but whenever I try to use the app on my personal phone i only get "test ads". I don't know why. I looked through the code of my app and can't find anything amiss. And i did delete the test version of the app and then download the released version from the market.

I'm not sure why the test ads are appearing in your app, but one way to shut them off is to go to your Admob App Settings, and choose the option "Disable test mode for all requests" as your Test Mode setting.

You customers would not have been seeing the debug ads. You probably have a line like:
AdManager.setTestDevices( new String[] {
AdManager.TEST_EMULATOR, // Android emulator
"E83D20734F72FB3108F104ABC0FFC738", // My T-Mobile G1 Test Phone
}
Assuming E83D20734F72FB3108F104ABC0FFC738 is you're personal phone, any time that phone makes a request it will get a test ad. All other phones will not be eligible for test ads, unless they are also individually added to that method.

Nick's answer works. (But is missing the final parenthesis.)
But what if I want to give my (not yet released) Android app out to 10 friends?
Is there any java code that says "treat ALL phones as test devices"?

Here is code for treat all devices as test devices:
String aid = Settings.Secure.getString(context.getContentResolver(), "android_id");
try {
Object obj;
((MessageDigest) (obj = MessageDigest.getInstance("MD5"))).update(aid.getBytes(), 0, aid.length());
aid = String.format("%032X", new Object[] { new BigInteger(1, ((MessageDigest) obj).digest()) });
} catch (NoSuchAlgorithmException localNoSuchAlgorithmException) {
aid = aid.substring(0, 32);
}
adRequest.addTestDevice(aid);