Android Question How can I read a file asychronously and then send it to a printer using write stream?

[davepamn]

I need to read a file as a input stream then using an asynchronous stream send the data to a zebra printer.

 

[Peter Simpson]

Hello,
What you need is the basics on reading a text file line by line https://www.b4x.com/android/forum/threads/text-files.6690/#content
and then you need to print to a Bluetooth printer (I presume that it's Bluetooth) https://www.b4x.com/android/forum/threads/android-serial-tutorial.6908/#post-39900
If the printer is not Bluetooth and it's USB then you will want this https://www.b4x.com/android/forum/threads/usbserial-library-2-0-supports-more-devices.28176/#content

 

[davepamn]

The Zebra GD200P is a blue tooth printer

 

[davepamn]

I created a service called "PrintService"

As part of the print service, I have an asychronous stream called "printer_astream"

Dim InputFile2 As InputStream=File.OpenInput(File.DirAssets, "RFID.xml")

        Dim buffer2() As Byte

        buffer2=Bit.InputStreamToBytes(InputFile2)

        PrintService.printer_AStream.Write(buffer2)

        printservice.printer_astream.close

This code produces a label the first time. However, the second time, the printer does nothing.

Is there a way to test the state of the stream? It seems like it is in a wait state.

 

[Erel]

Your code closes the stream too early. AStream.Write is not a blocking method.

If the printer doesn't send any response then you will need to use a timer to close the stream in a one or two seconds.

 

[davepamn]

You mentioned using a timer to close the stream, in one to two seconds. I can do that.

In the code samples I have been reading, they don't close the stream after writing.

 

[davepamn]

I was able to get the code to work.

I opened the serial object and stream in the service object and close the stream when the service is terminated.