Develop Reference

Using nested CoroutineScopes to upload images and keeping track of them

I am a newbie to android coroutines my requirements
Need to upload 20 images
Keep track of upload(at least when it gets finished I need to hide progressBar of each image)
After uploading all the images need to enable a "next" button also
Here is my try:
private fun startUploading(){
// Get AWS data
val accessKey = sharedPreferences.getString(getString(R.string.aws_access_key), "").toString()
val secretKey = sharedPreferences.getString(getString(R.string.aws_secret_key), "").toString()
val bucketName = sharedPreferences.getString(getString(R.string.aws_bucket_name), "").toString()
val region = sharedPreferences.getString(getString(R.string.aws_region), "").toString()
val distributionUrl = sharedPreferences.getString(getString(R.string.aws_distribution_url), "").toString()
var totalImagesNeedToUpload = 0
var totalImagesUploaded = 0
CoroutineScope(Dispatchers.IO).launch {
for (i in allCapturedImages.indices) {
val allImageFiles = allCapturedImages[i].viewItem.ImageFiles
totalImagesNeedToUpload += allImageFiles.size
for (j in allImageFiles.indices) {
CoroutineScope(Dispatchers.IO).launch {
while (true) {
val internetActive = utilsClassInstance.hasInternetConnected()
if (internetActive){
try {
val file = allImageFiles[j]
if (!file.uploaded) {
// Upload the file
val cfUrl = utilsClassInstance.uploadFile(file.imageFile, accessKey, secretKey, bucketName, region, distributionUrl)
// Set the uploaded status to true
file.uploaded = true
file.uploadedUrl = cfUrl
// Increment the count of total uploaded images
totalImagesUploaded += 1
// Upload is done for that particular set image
CoroutineScope(Dispatchers.Main).launch {
mainRecyclerAdapter?.uploadCompleteForViewItemImage(i, j, cfUrl)
// Set the next button enabled
if (totalImagesUploaded == totalImagesNeedToUpload){
binding.btnNext.isEnabled = true
}
}
break
}else{
totalImagesUploaded += 1
break
}
} catch (e: Exception) {
println(e.printStackTrace())
}
}
}
CoroutineScope(Dispatchers.Main).launch {
if (totalImagesUploaded == totalImagesNeedToUpload){
updateProgressForAllImages()
binding.btnNext.isEnabled = true
}
}
}
}
}
}
}
fun uploadFile(file: File, accessKey:String, secretKey:String, bucketName: String, region:String, distributionUrl: String): String{
// Create a S3 client
val s3Client = AmazonS3Client(BasicAWSCredentials(accessKey, secretKey))
s3Client.setRegion(Region.getRegion(region))
// Create a put object
val por = PutObjectRequest(bucketName, file.name, file)
s3Client.putObject(por)
// Override the response headers
val override = ResponseHeaderOverrides()
override.contentType = "image/jpeg"
// Generate the url request
val urlRequest = GeneratePresignedUrlRequest(bucketName, file.name)
urlRequest.responseHeaders = override
// Get the generated url
val url = s3Client.generatePresignedUrl(urlRequest)
return url.toString().replace("https://${bucketName}.s3.amazonaws.com/", distributionUrl)
}
There are total "n" images that I need to upload
every image is getting uploaded in different Coroutine because I need to do the parallel upload
The whole question is how to know that all the images are uploaded and enable a next button?

Your code seems very unstructured. You have an infinite loop checking for network availability. You have a nested loop here to upload images (Why?). You are creating a lot of coroutine scopes and have no control over them
Based on the 3 requirements that you mentioned in the question, you can do something like this:
val imagesToUpload: List<File> = /* ... */
var filesUploaded = 0
lifecycleScope.launchWhenStarted {
coroutineScope { // This will return only when all child coroutines have finished
imagesToUpload.forEach { imageFile ->
launch { // Run every upload in parallel
val url = utilsClassInstance.uploadFile(file.imageFile, ...) // Assuming this is a non-blocking suspend function.
filesUploaded++
// Pass the `url` to your adapter to display the image
binding.progressBar.progress = (filesUploaded * 100) / imagesToUpload.size // Update progress bar
}
}
}
// All images have been uploaded at this point.
binding.btnNext.enabled = true
}
Ideally you should have used a viewModelScope and the upload code should be in a repository, but since you don't seem to have a proper architecture in place, I have used lifecycleScope which you can get inside an Activity or Fragment

Upload Image to Server using Multipart and Request Body in Android in Kotlin

I am stuck in between a strange issue of uploading image file to server. Although I did upload file several times before, but this time I don't understand what is the issue.
I get the file path of respective file but RequestBody returns null. Below I mentioned what library I'm using.
I am using kotlin, MultiPart and RequestBody for file upload.
implementation 'com.squareup.retrofit2:retrofit:2.9.0'
implementation 'com.squareup.retrofit2:converter-gson:2.9.0'
implementation 'com.squareup.okhttp3:logging-interceptor:4.9.1'
Below is my code which I wrote for file upload. In which you can see GalleryCameraUtility.getImageRequestBody(imageFile) returns null for file.
File path from mobile device /storage/emulated/0/DCIM/Screenshots/test_image.jpg
fun addNewCompany(companyName: String, email: String,imageFile: File, ownerName: String, address: String, companyDetails: String){
val companyNameBody: RequestBody = companyName.toRequestBody("text/plain".toMediaType())
val emailBody: RequestBody = email.toRequestBody("text/plain".toMediaType())
val fileData: RequestBody? = GalleryCameraUtility.getImageRequestBody(imageFile)
val ownerNameBody: RequestBody = ownerName.toRequestBody("text/plain".toMediaType())
val addressBody: RequestBody = address.toRequestBody("text/plain".toMediaType())
val userIdBody: RequestBody = PreferenceHelper.readUserIdPref(Constants.USER_ID).toString()
.toRequestBody("text/plain".toMediaType())
addCompanyRepo.addNewCompanyApi(companyNameBody, emailBody, fileData, ownerNameBody, addressBody, userIdBody)
}
class GalleryCameraUtility {
companion object{
fun getImageRequestBody(sourceFile: File) : RequestBody? {
var requestBody: RequestBody? = null
Thread {
val mimeType = getMimeType(sourceFile);
if (mimeType == null) {
Log.e("file error", "Not able to get mime type")
return#Thread
}
try {
requestBody = sourceFile.path.toRequestBody("multipart/form-data".toMediaTypeOrNull())
/*MultipartBody.Builder().setType(MultipartBody.FORM)
.addFormDataPart(serverImageKey, uploadedFileName,sourceFile.asRequestBody(mimeType.toMediaTypeOrNull()))
.build()*/
} catch (ex: Exception) {
ex.printStackTrace()
Log.e("File upload", "failed")
}
}.start()
return requestBody;
}
// url = file path or whatever suitable URL you want.
private fun getMimeType(file: File): String? {
var type: String? = null
val extension = MimeTypeMap.getFileExtensionFromUrl(file.path)
if (extension != null) {
type = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension)
}
return type
}
}
}
I spent so many hours on this but not able to find solution. Please help me out on this.

download audio(file) from url to externalCache

I have audio 'url' "https://my-server.com/555.mp3"
how can I download it to "externalCacheDir" to be easy access without internet
i tried to use DownloadManager but i think there is better way to do it
fun downloadAudio(url:String){
val request = DownloadManager.Request(url.toUri())
val externalCachPath = getApplication<Application>().externalCacheDir!!.absolutePath
val fileName = "${UUID.randomUUID()}.3gp"
request.setDestinationInExternalPublicDir(externalCachPath,fileName)
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE)
request.setDescription("Download")
request.setTitle(fileName)
download(request)
return filename
}

How to POST multipart/form-data using Fuel for Kotlin?

I need to send a POST request to a server. I'm supposed to pass some parameters and an image. I am able to do this from Postman, but I can't do this on my Android app (latest SDK) using Fuel.
This is the code I'm using:
val formData = listOf("name" to "name")
val (_, _, result) = Fuel.upload("http://10.0.2.2:3000/test", parameters = formData)
.source { request, url -> imageFile } // type is File
.responseObject<CustomResponse>()
This is the postman screenshot:
I don't have access to the backend code, just some logs. It seems the request body is empty and the file also doesn't get uploaded. How can I do this? I'm at a loss.
I also tried passing the parameters as a jsonBody, this does submit the body, but the content type is not multipart/form-data and the image is still missing.
This JS code works:
let formData = new FormData();
formData.append('name', 'name');
formData.append('image', this.file);
axios.post(`${API_URL}/test`, formData, {
headers: {
'Content-Type': 'multipart/form-data'
}
}).then(console.log).catch(console.log)
Edit: I also tried passing the file as a DataPart, still nothing.

After some struggle I found out what would work:
val file = FileDataPart.from("path_to_your_file", name = "image")
val (_, _, result) = Fuel.upload("http://10.0.2.2:3000/test")
.add(file)
.responseObject<CustomResponse>()
I didn't need name-name part in my case but I would try to add InlineDataPart

After some try finally I found the solution.
Try this I think it will help.
val params = listOf("email" to "test#email.com", "pass" to "123456")
Fuel.upload("http://your-api-url.com/login", Method.POST, params)
.responseString { _, _, result ->
when (result) {
is Result.Failure -> {
print(result.getException().toString())
}
is Result.Success -> {
val data = result.get()
print(data)
}
}
}

I managed to send a POST request to a server. I passed a parameter and an image.
//Prepare POST body
val postBody = listOf("name" to "name")
//Call the API.
val (_, _, result) = Fuel.upload("http://10.0.2.2:3000/test", Method.POST , postBody)
.add(BlobDataPart(myInputStream, name = "image", filename = "default.jpg", contentType = "image/jpeg"))
.responseString()
//If failed, then print exception. If successful, then print result.
when (result) {
is Result.Failure -> {
println(result.getException())
}
is Result.Success -> {
println(result.get())
}
}
You can read the related documentation here.

Display pdf in android

I have written a c# web service that returns a pdf in a stream of bytes as response. Once I make a call to the web-service from my android app, I will store the response in an array byte till here I will be able to do it. But after that I need to convert that byte array into pdf, I should be able to display that. I have a menu page in which once the button is pressed the call is made to the web service with file name and on click of button I should be able to open pdf. Is this possible? Or there is some other, better solution? I checked on the net for better understanding, but I was unable to find one that could help me understand better.
Thanks for the suggestion, but I don't have the pdf in hand, I just have the array bytes, which I got from the web service. So I now need to regenerate the pdf from this array of bytes and display it, but I am not getting how to do it.

Try following these steps
Convert byte array to InputStream
val inputStream = ByteArrayInputStream(byteArray)
Save InputStream as PDF file:
suspend fun saveInputStreamAsPdfFile(inputStream: InputStream, applicationContext: Context): File? {
var outputFile: File? = null
withContext(Dispatchers.IO) {
try {
val directory = ContextCompat.getExternalFilesDirs(applicationContext, "documents").first()
val outputDir = File(directory, "outputPath")
outputFile = File(outputDir, UUID.randomUUID().toString() + ".pdf")
if (!outputDir.exists()) {
outputDir.mkdirs()
}
val outputStream = FileOutputStream(outputFile, false)
inputStream.use { fileOut -> fileOut.copyTo(outputStream) }
outputStream.close()
} catch (e: Exception) {
// Something went wrong
}
}
return outputFile
}
Show PDF with PdfRenderer
var totalPdfPages: Int
fun showPdf(pdfFile: File) {
val input = ParcelFileDescriptor.open(pdfFile, MODE_READ_ONLY)
val renderer = PdfRenderer(input)
val wrapper = PdfRendererWrapper(renderer)
totalPdfPages = wrapper.getTotalPages()
showPdfPage(0)
}
fun showPdfPage(currentPageIndex: Int) {
val pageBitmap = wrapper.getBitmap(currentPageIndex)
imageView.setImageBitmap(pageBitmap) // Show current page
}