App Inventor How to use USBManager without always asking the user permissions?

[Swisshornet93]

Hello,

I'm developing an application that use a USB device. Each time the device is reconnected, i must ask the user permission to connect to it.
The problem is that the smartphone and the device should work without an user intervention. Sometimes, the USB connector move a little bit and all my application is blocked because the permission are not granted anymore...

I found some tips for older versions of Android (...) but nothing for API 27...

Someone have a solution or a workaround to use a USB device without the user permission ?

Thx

 

[Deleted User]

What permission is your app requesting? Since Android 6.0 (API 23), the user is prompted confirm any "dangerous" permissions

https://developer.android.com/guide/topics/permissions/overview

 

[Swisshornet93]

After an enumeration of the USB devices connected on the USB connector, I was requesting the USB permission with the function UsbManager.requestPermission(device, id) for a specific device.
If i remove the requestPermission() function, I receive a runtime error.
If i use the function hasPermission() of the class UsbManager before asking the permission, each time the USB device is disconnected, it forget that it was already granted...

I finally found a workaround with this documentation: https://developer.android.com/guide/topics/connectivity/usb/host#permission-d
I use now an Intent Filter that start my application when a USB device (matching with my filter) is connected. It automatically receive the permission and don't show a popup anymore.

It's not the best way because I have to initialize all again in the function onResume() each time my USB device is detected.
If you have other ideas, please let me know and i'll try it.

 

[flyskywhy]

https://stackoverflow.com/questions/12388914/usb-device-access-pop-up-suppression/15151075#15151075 resolve the permission forget problem.