root-ansh

// converts any uri(content/file) to a local temp file first in cache directory for easy read/write
suspend fun Uri.toLocalFile(context: Context,localFileLocation:File = context.cacheDir): File? {
    val uri = this
    return withContext(Dispatchers.IO) {
        try {
            val fileInfo = FileInfo.fromSAFUri(context,uri)
            val fileName = fileInfo?.nameWithExtension?: "${System.currentTimeMillis()}.bin"
            val tempFile = File(localFileLocation, fileName)
            context.contentResolver.openInputStream(uri)?.use { inputStream ->
                FileOutputStream(tempFile).use { outputStream ->

root-ansh

data class FileInfo(
    val nameWithExtension: String,
    val extension: String?,
    val mimeType: String?,
    val size: Long?,
    val sizeFormatted: String?,
    val createdOn: Long?,
    val modifiedOn: Long?,
    val originalLocationPath: String?
){

root-ansh

private val saveFileToSystemSAF: ActivityResultLauncher<String> = registerForActivityResult(CreateDocument(mimeType = "*/*")) { result -> // or mimeType = "application/pdf" / "image/*" 
        val uri = result
        val file = state.fileToBeSaved // the file/bitmap that needs to be writteen to user selected uri
        val context = this
        if (uri!=null && file!=null){
            lifecycleScope.launch {
                context.saveFileToUserSelectedPath(uri,file) // writing file to user selected uri
                Snackbar
                    .make(binding.root,"Saved file :${file.name} to user selected directory", Snackbar.LENGTH_SHORT) 
                    .setAction("show"){context.openSystemViewerForSAFUri(uri)} //check next section for info on this

root-ansh

state = state.copy(fileToBeSaved = state.mediaFile) // state.copy(bitmapToBeSaved = getCurrentImageViewBitmap())
saveFileToSystemSAF.launch("MyFile.pdf")

root-ansh

lifecycleScope.launch {
     val uri = context.saveBitmapToUserMemory(getCurrentImageViewBitmap()) 
     val uri = context.saveFileToUserMemory(file)
     Snackbar
         .make(binding.root,"Saved file :currentlyVisibleImage to downloads", Snackbar.LENGTH_SHORT)
         .setAction("show"){context.openSystemViewerForSAFUri(uri)} //check next section for info on this
         .show()
                }

root-ansh

private fun getCurrentImageViewBitmap(): Bitmap{
        val drawable = binding.imagePreviewPlaceholder.drawable
        val bitmap = if (drawable is BitmapDrawable) {
            drawable.bitmap
        } else {
            val bitmap = createBitmap(drawable.intrinsicWidth, drawable.intrinsicHeight)
            val canvas = Canvas(bitmap)
            drawable.setBounds(0, 0, canvas.width, canvas.height)
            drawable.draw(canvas)
            bitmap

root-ansh

fun File.imageFileToBitmap(): Bitmap? { // wont work for content uri files. first create to local file
    val localNonSAFFile = this 

    return if (localNonSAFFile.exists()) {
        BitmapFactory.decodeFile(localNonSAFFile.absolutePath)
    } else {
        null
    }
}

root-ansh

@Throws
suspend fun Context.saveFileToUserSelectedPath(uri: Uri, sourceFile: File): Uri {
    return withContext(Dispatchers.IO) {
        contentResolver.openOutputStream(uri)?.use { outputStream ->
            sourceFile.inputStream().use { inputStream ->
                inputStream.copyTo(outputStream)
            }
        }
        uri
    }

root-ansh

@Throws
suspend fun Context.saveFileToUserMemory(
    sourceFile: File,
    targetDirectory: String = Environment.DIRECTORY_DOWNLOADS
): Uri {
    return withContext(Dispatchers.IO){
        if (!sourceFile.exists()) error("Source file does not exist")
        if(Build.VERSION.SDK_INT<Build.VERSION_CODES.Q) error("Saving to public directories is only supported on Android Q and above")
        val extension = sourceFile.extension.lowercase()
        val mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension) ?: "application/octet-stream"

root-ansh

fun Context.openSystemViewerForSAFUri(uri: Uri?) {
    uri?:return
    val mimeType1 = FileInfo.fromSAFUri(this,uri)?.mimeType
    val extension = MimeTypeMap.getFileExtensionFromUrl(uri.toString())
    val mimeType2 =  MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension.lowercase())
    val mimeType3 = "*/*"
    val intent = Intent(Intent.ACTION_VIEW).apply {
        setDataAndType(uri, mimeType1?:mimeType2?:mimeType3)
        addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION)
    }