List error when use Bluetooth Low Energy (BLE) extension

[VBLUno51]

Hi all,

I using MIT App Inventor2 to build an application that supports communication via Bluetooth Low Energy (BLE).

Everything is ok, but when I try to write bytes to BLE Device, I cannot. 

BluetoothLE.WriteBytes method have values argument with list format.

The error is: "Runtime error failed resolution Lcom/google/common/collect/List"

The below image is screen a part of my code.

Many thanks for your seeing!

[Abraham Getzler]

Could you post a complete Downloaded Blocks Image?

Maybe another part of your blocks is corrupting your list?

ABG

[VBLUno51]

Hi Abraham, many thanks for your attention.

I think that another parts of my blocks could work fine.

My blocks is attached in the below image.

[gerrikoio]

It's always worthwhile searching and reviewing old posts. This one, for example, should provide you with some help... "BLE Module Not Accepting List Argument for Value" 

[VBLUno51]

Hi gerrikoio, 

Thanks for your suggestion. I will do that at next post.

I could not modify the title of this post

[VBLUno51]

I have not fixed this problem yet.

[gerrikoio]

For now, use WriteStrings instead of WriteBytes. 

[VBLUno51]

I have just fixed the problem. 

To use BLE extensions for MIT AI2, must connect to AI Companion. 

When connect AI Companion, extension works fine. When use Build command, it did not works fine.

Many thanks for your seeing.

[Ghica]

Why did your app not work when you build it?
Is there an error message you can post here?
Cheers, Ghica.

[Robert Blaakmeer]

The problem has been around for some time, I have the same. The error is: "Runtime Error - Failed resolution of: Lcom/google/common/collect/Lists;"

It happens when using any of the WriteBytes / WriteShorts / WriteIntegers operations

See also this: https://groups.google.com/forum/#!searchin/mitappinventortest/lists$20error|sort:date/mitappinventortest/4lAXK0bJ9xc/IcFMH1vRAAAJ

this: https://groups.google.com/forum/#!searchin/mitappinventortest/lists$20error|sort:date/mitappinventortest/jaSdjEVGFJ8/H8Q_cti2AAAJ

and this: https://groups.google.com/forum/#!searchin/mitappinventortest/lists$20error|sort:date/mitappinventortest/AgAOhYKOvko/nUhTrIyqCgAJ

[Ghica]

I have seen the other threads, but it is confusing that you do not refer to them in your earlier post. I think I have also seen that there is a newer version in the works that fixes this bug. Maybe Evan can comment.
For now, it should be possible to find a workaround.
Cheers, Ghica.

[Dirk Loeckx]

I think I am having the same problem, and don't know how I should use the work-around. My goal is to send exactly the bytes 02:64:0A and 02:68:0A. If I try to send them with WriteBytes, I get the list error in the apk. If I try to send the Bytes as a string, I get a ' Unable to convert' error. Is there a way to make a literal string with non-ascii characters and/or convert a list of bytes to a string?

Code that works in companion-app but not in apk:

Code that raises the 'Unable to convert 2 of type gnu.math.IntNum to type java.lang.String' error:

Any help would be appreciated!

[Dirk Loeckx]

I found a solution myself, thanks to http://ai2.appinventor.mit.edu/?galleryId=5926305773387776 . You can (ab)use the Web component to convert byte to char (obviously, you need to add a Web component (from Connectivity) to your Screen for this to work. Now I still have a trailing 00 to the string, yet luckily my device seems to ignore this.