Android: Writing byteArray into file

Question

I'm trying to write a byteArray received from a server. This is my code

private fun writePdf(content: ByteArray) {

        val storageDir = getExternalFilesDir(Environment.DIRECTORY_DOWNLOADS)
        val file = File("${storageDir?.path}/", "${Date().time}Download.pdf")

        try {
//           file.writeBytes(archivo)
            val os = FileOutputStream(file, false)
            os.write(content)
            os.flush()
            os.close()
        } catch (e: IOException) {
            e.printStackTrace()
        }

        val intent = Intent(Intent.ACTION_VIEW)
        val uri = FileProvider
            .getUriForFile(
                this,
                this.packageName + ".fileprovider",
                file)
        intent.setDataAndType(uri, "application/pdf")
        intent.flags = Intent.FLAG_ACTIVITY_CLEAR_TOP

        try{
            startActivity(intent)
        }catch (e: Exception){
            e.printStackTrace()
            Toast.makeText(this, "Error", Toast.LENGTH_LONG)
                .show()
        }
    }

The problem is that when the pdf opens it is blank, like nothing has been written.

I've tried writing with FileOutputStream and File.writeBytes.
I've checked the byteArray (in case is corrupted or something) and it has no problems.
I've checked the length() of the file before and after writing, and it's length increases accordingly.

Thanks, any kind of help is appreciated.

Have you copied the PDF off of the device and compared it with the original? Note that this approach (putting the PDF content in a `ByteArray`) will only work for small PDFs. It would be better if you wrote the data to the file as you downloaded it, such as by using OkHttp and Okio -- see https://stackoverflow.com/a/29012988/115145 and various Kotlin ports in that same question. — CommonsWare, Apr 06 '22 at 21:21
@CommonsWare Hi, yes i tried that approach but got the same result. I think the problem lies on this method because I tested writing the content of a pdf directly (a pdf in the emulator device) on a new file using my code above and got the same result (the new file is blank). — navi95, Apr 07 '22 at 14:16

score 1 · Accepted Answer · edited Apr 08 '22 at 01:27

1

I finally found the problem, and solution. Everything with the code above was okay; the problem was that the flags for the intent to visualize the PDF were wrong. Instead of:

intent.flags = Intent.FLAG_ACTIVITY_CLEAR_TOP

It should be:

intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)

edited Apr 08 '22 at 01:27

Jeremy Caney

7,102
69
48
77

answered Apr 07 '22 at 19:06

navi95

23
5

Android: Writing byteArray into file

1 Answers1