Develop Reference

Android Open Document Tree with Activity Result Contract

I was recently updating deprecated methods in my App and there is one that I have a few questions about. Did not find any example or explanation describing my use case...
There is a local backup and a restore functions. User has to choose a directory either where to save data to or to restore data from. It was implemented like this:
binding.backupBtn.setOnClikListener{
openDirectory(LOCAL_BACKUP_CODE)
}
binding.restoreBtn.setOnClickListener{
openDirectory(LOCAL_RESTORE_CODE)
}
private fun openDirectory(requestCode: Int){
val intent = Intent(Intent.ACTION_OPEN_DOCUMENT_TREE)
startActivityForResult(intent, requestCode)
}
And then depending on the request code backup or restore:
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
if (resultCode = Activity.RESULT_OK) {
val uriTree = data?.data ?: return
if (requestCode == LOCAL_BACKUP_CODE) {
localBackup(uriTree)
}
if (requestCode == LOCAL_RESTORE_CODE) {
localRestore(uriTree)
}
}
}
Now with this Activity Result Contracts how can I specify, and is it possible at all, custom request code. Android documentation for accessing a directory still uses startActivityForResult()
Link
ActivityResultContract.StartActivityForResult() - is a generic contract that takes any Intent but there is no way to provide custom request code.
As for now I simply created 2 launchers for backup and restore:
val backupRequest = registerForActivityResult(ActivityResultContracts.OpenDocumentTree()){
if (it != null){
localBackup(it)
}
}
val restoreRequest = registerForActivityResult(ActivityResultContracts.OpenDocumentTree()){
if (it != null){
localRestore(it)
}
}
binding.backupBtn.setOnClickListener {
backupRequest.launch(null)
}
binding.restoreBtn.setOnClickListener {
restoreRequest.launch(null)
}
Is it the way to do it? I looked into custom Contracts, but can't figure out how I can return Uri AND custom variable (request code in this case).

How can I pass a variable control name to findViewById in Kotlin?

I am trying to learn Kotlin and I'm building a simple example as I go. I have 3 image buttons that open the camera and take a photo. The thumbnail is then set into an ImageView. I've used the examples from https://developer.android.com/training/camera/photobasics?hl=en to get the basics working (figuring if I can make it work for one, it'll work for all. It does indeed work for one, but I can't figure out how to make it one function that drops the thumbnail into the correct ImageView.
Inside my onCreate I have the listener for each of the buttons that will invoke the camera:
camRead1.setOnClickListener {dispatchTakePictureIntent() }
camRead2.setOnClickListener {dispatchTakePictureIntent() }
camRead3.setOnClickListener {dispatchTakePictureIntent() }
And I took the sample from the url above:
val REQUEST_IMAGE_CAPTURE = 1
private fun dispatchTakePictureIntent() {
val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
try {
startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE)
} catch (e: ActivityNotFoundException) {
// display error state to the user
}
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
val thumb: ImageView = findViewById(R.id.thumbRead1)
if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
val imageBitmap = data.extras.get("data") as Bitmap
thumb.setImageBitmap(imageBitmap)
}
}
and pasted it into my class MainActivity, and after I replaced imageView in the override function with a variable (thumb) and added the super, it worked perfectly for the first one.
However, I am trying to get 3 photos, read1, read2, and read3 which each need to display the thumb in thumbRead1, thumbRead2 and thumbRead3. I can't figure out how the onActivityResult is executed since the call inside dispatchTakePictureIntent is calling startActivityForResult (especially as Android Studio says that startActivityForResult is deprecated).
Obviously, once onActivityResult executes, I can see that thumb defines R.id.thumbRead1 and receives imageBitmap but I don't understand how I can make it aware of the button that was clicked.
Without understanding how onActivityResult is called, I'm thinking that if I can do something like:
findViewById(R.id("thumbRead" + imgID))
to define the specific ImageView that I want the photo pasted into. Am I on the right track here? If not, what is the recommended way of doing this?

Note they've recently added what's supposed to be a cleaner way of starting other activities for results and getting the results, explained here. But since you're already doing it the traditional way, I'll explain how to get that working.
I think the easiest thing to do in this situation is just make more request codes, so you can check which request it was.
val REQUEST_IMAGE_CAPTURE_SOURCE_1 = 1
val REQUEST_IMAGE_CAPTURE_SOURCE_2 = 2
val REQUEST_IMAGE_CAPTURE_SOURCE_3 = 3
//...
camRead1.setOnClickListener { dispatchTakePictureIntent(REQUEST_IMAGE_CAPTURE_SOURCE_1) }
camRead2.setOnClickListener { dispatchTakePictureIntent(REQUEST_IMAGE_CAPTURE_SOURCE_2) }
camRead3.setOnClickListener { dispatchTakePictureIntent(REQUEST_IMAGE_CAPTURE_SOURCE_3) }
//...
private fun dispatchTakePictureIntent(requestCode: Int) {
val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
try {
startActivityForResult(takePictureIntent, requestCode)
} catch (e: ActivityNotFoundException) {
// display error state to the user
}
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
if (resultCode != RESULT_OK) {
// possibly show message to user
return
}
val imageViewId = when (requestCode) {
REQUEST_IMAGE_CAPTURE_SOURCE_1 -> R.id.thumbRead1
REQUEST_IMAGE_CAPTURE_SOURCE_2 -> R.id.thumbRead2
REQUEST_IMAGE_CAPTURE_SOURCE_3 -> R.id.thumbRead3
}
val imageView = findViewById<ImageView>(imageViewId)
imageView.imageBitmap = data.extras.get("data") as Bitmap
}
By the way, if you want to get an ID for a view using the String like you were showing you were trying, you would do it like this:
val viewId = resources.getIdentifier("thumbRead$imgId", "id", packageName)
val imageView = findViewById<ImageView>(viewId)

You need to pass different request code for each call and pass it to the dispatchTakePictureIntent function. You do not need to get id by findviewbyid. You simply can add the image on the basis of the request code.
val REQUEST_IMAGE_CAPTURE_ONE = 1
val REQUEST_IMAGE_CAPTURE_TWO = 2
val REQUEST_IMAGE_CAPTURE_THREE = 3
private fun dispatchTakePictureIntent(requestCode: Int) {
val takePictureIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
try {
startActivityForResult(takePictureIntent, requestCode)
} catch (e: ActivityNotFoundException) {
// display error state to the user
}
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
if (resultCode == RESULT_OK) {
val imageBitmap = data.extras.get("data") as Bitmap
if (requestCode == REQUEST_IMAGE_CAPTURE_ONE ) {
thumbRead1.setImageBitmap(imageBitmap)
}else if (requestCode == REQUEST_IMAGE_CAPTURE_TWO ) {
thumbRead2.setImageBitmap(imageBitmap)
}else if (requestCode == REQUEST_IMAGE_CAPTURE_THREE ) {
thumbRead3.setImageBitmap(imageBitmap)
}
}
}

Get Image URI from Gallery and passing it to another activity, cannot see image, get an exception

I have an activity from which I launch the gallery, select an image, and want to display the selected image in another activity. I have referred to the following solution and implemented the same.
How to get Image URI from Gallery?
Though I am able to pass the URI to the next activity, I cannot see anything on the image view. Any help as to where I am going wrong, appreciated.
btn_launch_gallery.setOnClickListener {
val requestCode = 0
val launchGalleryIntent = Intent(Intent.ACTION_PICK,
MediaStore.Images.Media.EXTERNAL_CONTENT_URI)
startActivityForResult(launchGalleryIntent, requestCode)
}
My OnActivityResult looks like this, basically implemented the same as given in the example cited above.
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
if (requestCode === 0 && resultCode === Activity.RESULT_OK ) {
val selectedImage: Uri? = data?.data
val picturePath = getRealPathFromURI(
selectedImage,
this
)
val intent = Intent(this, LogFoodDetail::class.java)
intent.putExtra("image_from_gallery", picturePath)
try {
startActivity(intent)
}
catch (e: Exception)
{
e.printStackTrace()
Log.e("Error",e.printStackTrace().toString())
}
}
}
fun getRealPathFromURI(contentURI: Uri?, context: Activity): String? {
val projection =
arrayOf(MediaStore.Images.Media.DATA)
val cursor = context.managedQuery(
contentURI, projection, null,
null, null
)
?: return null
val column_index = cursor
.getColumnIndexOrThrow(MediaStore.Images.Media.DATA)
return if (cursor.moveToFirst()) {
// cursor.close();
cursor.getString(column_index)
} else null
// cursor.close();
}
In my next activity, I getting the intent like this and passing the URI to ImageView. However, I cannot see the image. I get the following error - W/System.err: java.io.FileNotFoundException: No content provider: /storage/emulated/0/DCIM/Camera/***.jpg
val resId = intent.getStringExtra("image_from_gallery")
val imgThumbnail: ImageView = findViewById(R.id.food_thumbnail)
try{
val imageStream: InputStream? = contentResolver.openInputStream(Uri.parse(resId))
val bitmap = BitmapFactory.decodeStream(imageStream)
imgThumbnail.setImageBitmap(bitmap)
}
catch (e: Exception)
{
e.printStackTrace()
}
I see the following image in the next activity:
UPDATE:
As commented by #blackapps in his answer passing the URI as a string to the next activity on an intent.putExtra() and resolving the URI in the subsequent activity solved it, the updated code in OnActivityResult() is,
...
val selectedImage: Uri? = data?.data
val intent = Intent(this, LogFoodDetail::class.java)
intent.putExtra("image_from_gallery",
selectedImage.toString())
startActivity(intent)

Dont convert a nice uri to a file system path.
Uri uri = data.getData();
Pass the obtained uri directly to the next activity.
And there you can use it for
imageView.setImageUri(uri);
Instead of the uri you can also pass the uri as string with uri.toString().

You can directly load an local image Uri using:
imgThumbnail.setImageUri(yourUri);
Instead of sending the string path to the activity, you should send the raw uri and then set it directly to the imageView.

How can I set a request code under different conditions for my activity to bypass onActivityResult?

I have a program that allows me to store data(pictures and metadata with the taken picture) during the execution of a picture being taking with the android system camera activity... but I have code in place to make sure that the user enters data into a popup activity before the camera activity is displayed by using the OnActivityResult function(this way the user's photo has information that is stored as metadata in my firebase database). I was wondering If I can set a request code that wouldn't be equal to the REQUESTCODE2 so that under the condition that my back button is pressed(which will still result in the REQUESTCODE2 being returned for the com.example.myapplication.nameofphoto activity, which then will trigger takepic()) I can purposely make sure that the request code is faulty so that takepic() does not trigger and I don't store null data into my database.
for your information: nameofpersonvar , and nameofphotovar are both in a different class and is the information from the popup activity
private const val REQUESTCODE = 2
private const val REQUESTCODE2 = 3
fun take_pic(){
val takephotoIntent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
if (takephotoIntent.resolveActivity(this.packageManager) != null) {
startActivityForResult(takephotoIntent, REQUESTCODE)
} else {
Toast.makeText(this, "Unable To access Camera... ", Toast.LENGTH_LONG)
.show()
}
}
photoButton.setOnClickListener {
val action3 = Intent(this , com.example.myapplication.nameofphoto::class.java)
startActivityForResult(action3, REQUESTCODE2 )
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
if (REQUESTCODE == requestCode && resultCode == Activity.RESULT_OK) {
//Compressing the bitmap(image) into a byte[] to match the input of the .putbytes method
val userimage = data?.extras?.get("data") as Bitmap
val byteoutput = ByteArrayOutputStream()
userimage.compress(Bitmap.CompressFormat.JPEG,100 , byteoutput)
val data = byteoutput.toByteArray()
//ref to the firebase "bucket" database
val storageinfo = FirebaseStorage.getInstance().getReference("/Images" )
//extra data that shows who the images belong to (users)
val metadatastoreage = storageMetadata {
setCustomMetadata("Name of person" , nameofpersonvar)
setCustomMetadata("Name of photo" , nameofphotovar)}
storageinfo.putBytes(data, metadatastoreage)
}else if (requestCode ==REQUESTCODE2) {
take_pic()
}
else {
super.onActivityResult(requestCode, resultCode, data)
}
}

Then why don't you send some result code different from the back press method of the current activity opened and check if the result is successful then take pick otherwise do something.
send this as result code from back press method. RESULT_CANCELED
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
if (REQUESTCODE == requestCode && resultCode == Activity.RESULT_OK) {
//Compressing the bitmap(image) into a byte[] to match the input of the .putbytes method
val userimage = data?.extras?.get("data") as Bitmap
val byteoutput = ByteArrayOutputStream()
userimage.compress(Bitmap.CompressFormat.JPEG,100 , byteoutput)
val data = byteoutput.toByteArray()
//ref to the firebase "bucket" database
val storageinfo = FirebaseStorage.getInstance().getReference("/Images" )
//extra data that shows who the images belong to (users)
val metadatastoreage = storageMetadata {
setCustomMetadata("Name of person" , nameofpersonvar)
setCustomMetadata("Name of photo" , nameofphotovar)}
storageinfo.putBytes(data, metadatastoreage)
return
}
if (requestCode ==REQUESTCODE2 && resultcode == Activity.RESULT_OK) {
take_pic()
} else {
//back pressed do something.
//finish etc
}
}
Edit: You can override the onBackPressed() in the popup activity and send some data using intent to the parent activity. for ex.
Intent resultIntent = new Intent();
// TODO Add extras or a data URI to this intent as appropriate.
resultIntent.putExtra("user_pic_click", "some data");
setResult(Activity.RESULT_OK, resultIntent);
finish();

How to get base64 from file's URI?

In general, my task is to get base64 from chosen file. In order to open File Browser, I call following function:
private fun showFileBrowser() {
val intent = Intent(Intent.ACTION_GET_CONTENT)
intent.setType("*/*")
startActivityForResult(intent, FILE_CHOOSE_REQUEST_CODE)
}
It is successfully opened. When some file is chosen, onActivityResult is called. Here it is:
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
super.onActivityResult(requestCode, resultCode, data)
if (requestCode == FILE_CHOOSE_REQUEST_CODE) {
// not that data.data is Uri
if(data != null && data.data != null) {
val encodedBase64 = getBase64FromPath(data.data.path)
print(encodedBase64)
}
}
}
Here is how I convert File to base64:
private fun getBase64FromPath(path: String): String {
try {
val bytes = File(path).readBytes()
return Base64.encodeToString(bytes, Base64.DEFAULT)
} catch (error: IOException) {
error.printStackTrace() // This exception always occurs
}
}
Seems like I do everything right, but I get FileNotFoundException. I don't know what is the reason for this. I didn't add any permission, because I don't to write anything to scared, I just want a user to choose a file, I will convert it to base64 and send it to the server. So, what is the problem this my code?

my task is to get base64 from chosen file
Your code has little to do with files. ACTION_GET_CONTENT is not limited to files on the device, let alone files on the filesystem that you can access.
When some file is chosen, onActivityResult is called
You get a Uri via onActivityResult(). A Uri is not a file, and getPath() on a Uri only has meaning if the scheme of that Uri is file. Most Uri values will have a scheme of content.
Replace your function with:
private fun getBase64ForUriAndPossiblyCrash(uri: Uri): String {
try {
val bytes = contentResolver.openInputStream(uri).readBytes()
return Base64.encodeToString(bytes, Base64.DEFAULT)
} catch (error: IOException) {
error.printStackTrace() // This exception always occurs
}
The AndPossiblyCrash portion of the function name is because you are going to run out of memory if the content is too large. Also note that you are doing this work on the main application thread, so your UI will be frozen while you are reading this in.