B4J Question [SOLVED],[BANano], Help me with banano.GetFileAsArrayBuffer

[NGUYEN TUAN ANH]

Dear All,
Hope you all have a good day off and enjoy the WordCup2022
My Code:

Dim GetFileArr As ResumableSub = banano.GetFileAsArrayBuffer("./assets/biendong8.sea",Null)
wait for (GetFileArr) Complete (TempArr As Object)

But i can not get Values from TempArr
Could you please help me Get Value from TempArr
Thank you very much
I am waiting for you
Best Regards

 

[Mashiane]

Try...

Dim TempArr As Object = Banano. Await(banano.GetFileAsArrayBuffer("./assets/biendong8.sea",Null))
Log(TempArr)

 

[alwaysbusy]

Are you sure 'biendong8.sea' exists (and did you pressed the sync button in the IDE?) because this should work. Also, this has to run from a real Web Server else you will get a CORS error.

Alwaysbusy

 

[NGUYEN TUAN ANH]

Try...

Dim TempArr As Object = Banano. Await(banano.GetFileAsArrayBuffer("./assets/biendong8.sea",Null))
Log(TempArr)

Thanks your Reply, i will try again

 

[NGUYEN TUAN ANH]

Are you sure 'biendong8.sea' exists (and did you pressed the sync button in the IDE?) because this should work. Also, this has to run from a real Web Server else you will get a CORS error.

Alwaysbusy

Thank your reply
I am running im Localhost, and biendong8.sea is existing in my ./assets/

 

[NGUYEN TUAN ANH]

Try...

Dim TempArr As Object = Banano. Await(banano.GetFileAsArrayBuffer("./assets/biendong8.sea",Null))
Log(TempArr)

Log(TempArr) Result:

1. ArrayBuffer(30408000)
   1. byteLength: 30408000
   2. [[Prototype]]: ArrayBuffer
   3. [[Int8Array]]: Int8Array(30408000)
   4. [[Uint8Array]]: Uint8Array(30408000)
   5. [[Int16Array]]: Int16Array(15204000)
   6. [[Int32Array]]: Int32Array(7602000)
   7. [[ArrayBufferByteLength]]: 30408000
   8. [[ArrayBufferData]]: 48

But i don't know, how to get some value from ArrayBuffer(30408000)
I had set: Dim TestArr() as Byte = TempArr, But not success

 

[Mashiane]

What are you trying to achieve by using GetFileAsArrayBuffer?

 

[NGUYEN TUAN ANH]

What are you trying to achieve by using GetFileAsArrayBuffer?

I want to read the Byte array element values stored in the binary file biendong8.sea for further computation.
biendong8.sea is a binary file, I created it on B4A with code:

Dim TempArr() As Byte
File.WriteBytes(Dir, "biendong8.sea", TempArr)

and on B4A I read it in code:

Dim TempArr() As Byte = File.ReadBytes(File.DirAssets, "biendong8.sea")
Log(TempArr(1000))

and get a result in debug is: 17
But in B4j BananoVuetifyAD3 I made the code:

Dim TempArr As Object = Banano. Await(banano.GetFileAsArrayBuffer("./assets/biendong8.sea",Null))
Dim TestArr() as Byte = TempArr
Log(TestArr(1000))

Then only get the result in Debug is: undefined

 

[alwaysbusy]

Try the following (I used an image file here, but it should work with your type of file too):

ArrayBuffers in JavaScript are 'raw' data and have to be accessed with a 'view'. This view can be a Uint8Array, a Uint16Array, a Uint32Array or a Float64Array
In your case, I believe you need a Uint8Array.

Dim GetFileArr As ResumableSub = BANano.GetFileAsArrayBuffer("./assets/banano.jpg",Null)
wait for (GetFileArr) Complete (TempArr As Object)
 
' create a Uint8Array 'view' (an array of bytes)
Dim Uint8View As BANanoObject
Uint8View.Initialize2("Uint8Array", TempArr)
Dim bytes() As Byte = Uint8View ' convert it to a B4J byte array so we can access it more easily
  
Log(bytes(1000))

Alwaysbusy

 

[NGUYEN TUAN ANH]

Try the following (I used an image file here, but it should work with your type of file too):

ArrayBuffers in JavaScript are 'raw' data and have to be accessed with a 'view'. This view can be a Uint8Array, a Uint16Array, a Uint32Array or a Float64Array
In your case, I believe you need a Uint8Array.

Dim GetFileArr As ResumableSub = BANano.GetFileAsArrayBuffer("./assets/banano.jpg",Null)
wait for (GetFileArr) Complete (TempArr As Object)
 
' create a Uint8Array 'view' (an array of bytes)
Dim Uint8View As BANanoObject
Uint8View.Initialize2("Uint8Array", TempArr)
Dim bytes() As Byte = Uint8View ' convert it to a B4J byte array so we can access it more easily
 
Log(bytes(1000))

Alwaysbusy

Thank you very much
I followed your instructions and was successful as expected

 

[alwaysbusy]

@NGUYEN TUAN ANH Please mark my post as the answer and change the title of this topic prefix to [BANano] instead of [BANanoVuetifyAD3] as this is a general BANano question. This way, people using pure BANano can also find the answer more easily.

Alwaysbusy