Android Library for Printing Features?

[zeitwesen]

Hi,

Thanks for your project - it works great. But as I have built my own Android-App to cover and automate my daily hustles in digital life I though of a feature to "just print" some photos via "Sharing" in Android. For that I am searching for a library, that I can easily integrate into my own Android app project. Do you plan to port/wrap your "printer communication" code so it has a nice API so I can use it inside my app?

Maybe other use-cases arise from that - e.g. use it as a receipt printer in an account app, printing notes, etc...

What do you all think?

[NaitLee]

Though this codebase may be used like a library, it isn’t specifically designed for Android, as there are just some Python code.

That said, if you have ability to develop for Android, it should be easy to program the printers’ protocol, produce data with it, and send to devices via Android API for bluetooth. (also some code to interact with printer)

With some references and a library (for bluetooth), that just costed me 3 days or so in Python. I’m novice to such “project” that time.

I’d also share something for connection to the printer. Any other problem just ask :)

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These printers are Bluetooth Low Energy (BLE) peripherals.
They behave as servers. Once a client (your PC or mobile phone) connects to it, some services are provided for interaction.
Each service have some characteristics, that you can read and/or write data to, or receive notification data from.
Both services and characteristics are referenced by their UUIDs.

When scanning for BLE devices, the devices may include their service they provide in the announcement data.
This can be used to filter out devices, to take only what we want.

For these printers, just care about these:

Description	UUID
Announced service UUID to filter out supported printers	0000af30-0000-1000-8000-00805f9b34fb
Service UUID to get after connection to device’s GATT server	0000ae30-0000-1000-8000-00805f9b34fb
Characteristic to write produced data to (writeWithoutResponse)	0000ae01-0000-1000-8000-00805f9b34fb
Characteristic to receive pause/resume notification from	0000ae02-0000-1000-8000-00805f9b34fb

(Note: yes, the printer’s announced service doesn’t correspond to what it really have, we can just ignore that fact)
(Also, don’t filter printers by their device name. It’s a bad design that I have to admit.)

I’m planning to make another frontend using Web Bluetooth API, using all of these. That may serve a better example in the future, in case this codebase couldn’t convince.

[NaitLee]

The new project kitty-printer serves an example, especially this file.