Develop Reference

How to access single USB devices of a Composite USB device?

I would like to send data from my Windows computer to my Android Mobile.
For this, I need to activate the Accessory mode of the Android device and the USB Host mode on the Windows device.
On my Windows computer, I have a USB Composite device for the Android Mobile. This Composite USB device bundles several interfaces: Enumeration of USB Composite Devices.
Unfortunately, I can't find information how I can access the single devices of a Composite device.
I want to get a device id / path, which I can open with CreateFile to use the created HANDLE for opening a WinUsb handle with WinUsb_Initialize.
But if I try to open a Composite USB device with CreateFile, I get a ERROR_NOT_ENOUGH_MEMORY result.
I'm using this code:
_deviceHandle = CreateFile(
deviceId, GENERIC_READ | GENERIC_WRITE, FILE_SHARE_NONE, NULL,
OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
... with the filename "\?\USB#VID_04E8&PID_6864#RF8NB0NMT0X#{a5dcbf10-6530-11d2-901f-00c04fb951ed}"
It's a GUID_DEVINTERFACE_USB_DEVICE device id for a Samsung Galaxy mobile with enabled USB debugging.
As the driver Windows uses ssudbus2.sys, Version 2.17.16.0 (2021-09-14) from Samsung Electronics Co. Ltd.
The app MyPhoneExplorer can access to my mobile. So it a solution without a special driver must be possible.
How can I get this device id / path of the single USB devices inside a Composite USB device?

The filename you are using represents the overall USB device; it doesn't represent any particular instance. A filename that represents interface will have something like &mi_01 right after the product name, where 1 is the 0-based interface number.
You might be able to just insert the appropriate &mi_xx string into your filename at the appropriate place and get it work. I think you'd also need to modify the GUID at the end of the string, which is the device interface GUID.
The more standard way to find the filename in code is to use the SetupAPI and the configuration manager (CM) API to iterate through all the child devices of your USB device. Look for a child whose device instance ID (retrieved with CM_Get_Device_ID) contains MI_xx where xx is the two-digit interface number you are looking for.
It takes a lot of effort to write up this code in standalone form, and test it, and debug it, so I will not be presenting you with a working code example. Instead, I encourage you to look at the working code in the get_interface_composite function of libusbp which does what you need to do:
https://github.com/pololu/libusbp/blob/759f48d/src/windows/interface_windows.c#L86
There are some more steps to get the path of that device node. And then the code that actually calls CreateFile and WinUsb_Initialize is here:
https://github.com/pololu/libusbp/blob/759f48d/src/windows/generic_handle_windows.c#L56-L77

Android 10 injecting inputs to External Display / Virtual Display

Concept:
I have an Android application written in Kotlin that simply launches an Android application on an external display. The display could be a AirServer, Miracast, Microsoft Connect, USB-OTG HDMI, USB-C HDMI, or a Simulated Secondary Display (see screenshot).
Here's the except of the code that does the "heavy lifting":
val intent = packageManager.getLaunchIntentForPackage(info.id)
val dm = recyclerView.context.getSystemService(Service.DISPLAY_SERVICE) as DisplayManager
val displays = dm.getDisplays(DisplayManager.DISPLAY_CATEGORY_PRESENTATION)
for (display in displays) {
val options = ActivityOptions.makeBasic()
options.launchDisplayId = display.displayId
recyclerView.context.startActivity(intent, options.toBundle())
break
}
The applications start fine. See the screenshot, where I used it to launch Minecraft Pocket Edition to a Simulated Secondary Display (as if an external HDMI monitor was connected). The issue is that I cannot send touch or cursor inputs to the virtual displays.
What Works:
adb shell input -d <display-id> tap <x> <y>
Wireless Controllers
Wireless Keyboards
What Doesn't Work:
Wireless / Wired Mice (cursor hits the edges of the phone screen, never enters the Virtual Display / External Display screen)
Touch (see screenshot)
What I've Tried:
The output of dumpsys display reveals that the Virtual Displays all lack the touch VIRTUAL parameter that the internal display has. I'm not sure if this means that the display itself doesn't support touchscreen input, or if it's simply not enabled.
I tried forcing the application into the foreground, which made the apps detect keyboard and controller inputs, but the cursor was still locked to the internal display window.
It's worth noting that the Android 10 Desktop Mode Developer Setting DOES put the cursor into the external display instead of the internal display. This is what I'm trying to accomplish.
There appears to be a hidden Java API within Androids SDK:
https://github.com/aosp-mirror/platform_frameworks_base/blob/a4ddee215e41ea232340c14ef92d6e9f290e5174/services/core/jni/com_android_server_input_InputManagerService.cpp#L825
I attempted to access this class via reflection and call setFocusedDisplay, but I kept getting ClassNotFound exceptions, even with the private API blacklist secure settings changed.
Any help would be appreciated here. The only other related threat to this one is here, and it was never solved:
Android Q VirtualDisplay touch input events

I've solve my problem. The input directed to the external display is controlled by the Android internal framework. By default, external mice are directed to the internal display. To have them go to the external display, Force Desktop Mode must be enabled in Developer Settings. There is currently no other way to forward the pointer.

How can I read files from usb device on android?

I'm trying to create something like file explorer through connected usb devices(via OTG or usb ports on android TV).
All I need for this is a path something like "/storage/sda4" and device identifier, and then I can work with device through simle android class File. Is sounds simple but I can't find any info about this, but all file explorers can do it (for example ESExplorer).
Ok, I find a simple way to get all connected usb devices with identifier
UsbManager usbManager = (UsbManager) context.getSystemService(Context.USB_SERVICE);
usbManager.getDeviceList();
but how can I get an info about path? deviceName contains something like this "/dev/bus/usb/00x" but it can't help me, I need simple emulated android path ("/storage/sda4"). This page https://developer.android.com/guide/topics/connectivity/usb/host.html tells that I need to get UsbInterfaces and make UsbConnection to bulk transfer and other bullshit, I done it all but didn't find path to device or any other info about usb file list.
Ok, I find another way to get (that don't requires permission!) to get path to all connected devices
StorageManager storageManager = (StorageManager) context.getSystemService(Context.STORAGE_SERVICE);
Method getVolumeListMethod = StorageManager.class.getDeclaredMethod("getVolumeList");
Object[] storageVolumeList = (Object[]) getVolumeListMethod.invoke(storageManager);
and it works but I need to identify a device(because I want to cache files of different usb storages) but all that I can get from volume object is mStorageId, mDescriptionId, mPrimary, mRemovable, mEmulated, mMtpReserveSpace, mAllowMassStorage, mMaxFileSize, mOwner, mUuid, mUserLabel, mState, mSubSystem.
None of this can not identify the device: mDescriptionId and mStorageId are
unique fot usb port, mUuid is null, mUserLabel is not unique.
Environment.getExternalFilesDirs() won't help, it don't provide any device id and works only with one device.
I find a similar question here, but it has no right answer Android list files from USB Drive.
Well, is a simple way to get list of usb devices with path and identifier exists?

All I need for this is a path something like "/storage/sda4" and device identifier, and then I can work with device through simle android class File
No, because you do not have arbitrary access to removable storage, including USB OTG drives, on Android 4.4+.
all file explorers can do it (for example ESExplorer)
Pre-installed "file explorer" apps may have additional rights granted to them by the device manufacturer or custom ROM developer. Otherwise, they too do not have arbitrary access to removable storage.
is a simple way to get list of usb devices with path and identifier exists?
Not with a filesystem path, no. getStorageVolumes() on StorageManager will give you a list of storage volumes, which includes external storage and removable storage. You can then use createAccessIntent() on StorageVolume to ask the user for permission to work with the volume. If they grant permission, you get a Uri back that:
Serves as a temporary identifier for the volume (i.e., will no longer be usable as an identifier if the user ejects the media, but until then, can distinguish one volume from another), and
Lets you work with a portion of the contents of that volume, though using Uri values, not filesystem paths

Cast icon not showing for custom receiver

I have followed the CastHelloText-android example on github. When I use either the receiver they specified in the demo or the default receiver, the cast icon shows up in my application.
However, as soon as I change the app_id to be the one provided by the Google Cast SDK Developer Console for my registered application, the icon doesn't show.
I've tried rebooting my chromecast and my android device. All to no avail.
Any suggestions?

Make sure the serial number for the device that you have registered on the dev console is correct, it is sometimes hard to read the serial number (take a picture and zoom in). Also make sure the checkbox that sends the serial number is checked when you setup you chromecast. If cast icon doesn't show up for your own app-id but shows up for the other one, then there is an issue with your app/device registration.

I had the same issue as Kimble above. I started with the serial number on my Nvidia shield, which didn't work because that's not the serial number for the Chromecast. The proper serial number can be found in the settings menu under "Chromecast built-in".

I know I am late to the party, but here is a probably more up-to-date solution. Following this documentation solved my problem: https://developers.google.com/cast/docs/registration#find_device_serial_number
According to the documentation, for cast-enabled Android TVs, the serial number can be found in the following way:
Android TV (ATV) devices have multiple serial numbers associated with them. The software (Cast) serial number can be obtained either by casting the Cast Developer Console page to the ATV device as outlined above, or by putting the ATV device into developer mode and looking in the Cast settings for the software serial number.
To put your ATV device into developer mode, navigate to Settings > System > About > Android TV OS build, and click on the build several times until the device notifies you that you are in developer mode. To find the serial number once in developer mode, navigate either to Settings > Device Preferences > Chromecast built-in or Settings > System > Cast, depending on your ATV model, and you'll see the software serial number displayed.
Also, since just by looking at the screen there is no way to disambiguate zero and capital O, or small L and capital I, etc., you can simply cast the page in the link above to read out the serial number for you:
To find the serial number of any device, you can cast the Cast Developer Console page to the device:
Click the Cast button (as if you were casting this page).
The prompt displays Cast tab and lists the available devices.
From the drop-down menu, select the device for which you want to obtain the serial number.
For display devices, the serial number displays on the TV screen and is read aloud on the TV speakers (to help disambiguate 0's and O's).
For audio devices, the serial number is read aloud on the speaker being cast to.

Channel Listing in Google TV not showing channels

I'm testing Googl's 'Channel Changing Example' on my Sony Google TV.
I'm connected to a DVB (Digital Video Broadcasting) through the HDMI port.
When i'm running the example the number of retrieved channels is 0.
Just to be clear, I can see the TV channels using the 'Live TV' in the TV itself.

You need to make sure that your selected device has a channel lineup. Based on the fact that you're using DVB, I'm guessing you're not in the US, which means you aren't really using this in a supported country. However, you can fake it by going to Settings > Video input > Configured devices > (whatever your TV source is) > Edit channel lineup and then go through the prompts. This will download the list of channels for your connected set top box (again, this is probably not going to be your real lineup, but enough for you to test out the sample.