BiometricPrompt requires either Fragment or FragmentActivity in its constructor. I cannot find out how to use BiometricPrompt from a Composable screen, not in the documentation, not in any tutorial. Has anyone in here dealt with the same problem? Or is there any other way to use biometric authentication in a fully Compose built application?
Subclass your MainActivity from FragmentActivity, then in composable get your context:
val context = LocalContext.current as FragmentActivity
Check out some examples on github: https://github.com/search?l=kotlin&q=BiometricPrompt%20composable&type=Code
Ok, it was quite simple in the end, but has taken me hours, so here is the answer for anyone struggling with this.
Make sure, that your MainActivity inherits from FragmentActivity(). Then you will be able to cast LocalContext.current to FragmentActivity.
val context = LocalContext.current as FragmentActivity
val biometricPrompt = BiometricPrompt(
context,
authenticationCallback
)
replace ComponetActivity() with FragmentActivity() then use normal compose view from FragmentActivity()
setContent {
FingerPrintAppTheme {
// A surface container using the 'background' color from the theme
Surface(
modifier = Modifier.fillMaxSize(), color = MaterialTheme.colorScheme.background
) {
Greeting("Android")
}
}
}
then everything works fine
For those that cannot change their activity base class, there is issuetracker.google.com/issues/178855209 to request for a biometric-compose artifact. Unfortunately, as of version 1.2.0-alpha04 no work has been done towards it.
You can inherit from AppCompatActivity, which inherits from FragmentActivity, which inherits from ComponentActivity.
Then you can do:
inline fun <reified Activity : FragmentActivity> Context.getActivity(): Activity? {
return when (this) {
is Activity -> this
else -> {
var context = this
while (context is ContextWrapper) {
context = context.baseContext
if (context is Activity) return context
}
null
}
}
}
and then:
val activity = LocalContext.current.getActivity<MainActivity>()
val biometricPrompt = BiometricPrompt(
activity,
authenticationCallback
)
Related
Whenever I tell my NavGraph to start on this composable screen:
#Composable
fun LiveTrainingScreen(viewModel: LiveTrainingViewModel = viewModel(), navController: NavController) {
viewModel.context = LocalContext.current
viewModel.scope = rememberCoroutineScope()
viewModel.navController = navController
val largeVideoPlayerHandler = viewModel.InitLargeVideoDisplay(CameraLink.cockPitRight) //exoplayer saved within this handler and refrences is made within the viewModel
val smallVideoPlayerHandler = viewModel.InitSmallVideoDisplay(CameraLink.navigationAndAltitudeDisplay) //exoplayer saved within this handler and refrences is made within the viewModel
//lots of code
}
and when I want to switch the mediaType/video that is being displayed of the Exoplayer this function will work:
class LiveTrainingViewModel(application: Application) : AndroidViewModel(application) {
fun SwitchLargeVideoDisplay(cameraLinkObject: CameraLinkObject) {
UpdateLargeVideoDisplayCameraLinkObject(cameraLinkObject)
largeVideoDisplay.videoPlayer.setMediaItem(MediaItem.fromUri(cameraLinkObject.url))
largeVideoDisplay.videoPlayer.prepare()
}
}
But whenever I load this Screen from another screen this large screen update function won't work for some reason?
Does anybody know why?
I am creating a Custom Linear Layout view to represent a custom calender. Ealier I used SQlitehelper to get the data. But now I am migrating to Room DB. But I couldn't instantiate AndroidViewModel and get data.
This is the AndroidViewModel
class AdminExpensesVM(application: Application):AndroidViewModel(application) {
private val repository:AdminExpensesRepo
val readAll :LiveData<List<AdminExpensesData>>
init {
val adminExpensesDB=AdminExpensesDatabase.getInstance(application).adminExpensesDao
repository= AdminExpensesRepo(adminExpensesDB)
readAll=repository.getAllExpenses()
}
}
This is the Custom LinearLayout
class Admin_Calender : LinearLayout {
private lateinit var adminExpensesVM: AdminExpensesVM;
constructor(context: Context?, attrs: AttributeSet?) : super(context, attrs) {
val inflater = context.getSystemService(Context.LAYOUT_INFLATER_SERVICE) as LayoutInflater
val view: View = inflater.inflate(R.layout.admin_calender, this)
adminExpensesVM=ViewModelProvider.AndroidViewModelFactory.getInstance(context as Application).create(AdminExpensesVM::class.java)
}
}
But this cannot be done becasue it get a error casting context to application. How can I do this? Is there anyway to get application to instantiate AndroidViewModel or is there any way to do it with only context?
Thank you
I don't really get your question but maybe this can help try to make it scoped with your activity
val adminExpensesVM: AdminExpensesVM by activityViewModels()
viewModelScope blocks UI in Jetpack Compose
I know viewModelScope.launch(Dispatchers.IO) {} can avoid this problem, but how to use viewModelScope.launch(Dispatchers.IO) {}?
This is my UI level code
#Composable
fun CountryContent(viewModel: CountryViewModel) {
SingleRun {
viewModel.getCountryList()
}
val pagingItems = viewModel.countryGroupList.collectAsLazyPagingItems()
// ...
}
Here is my ViewModel, Pager is my pagination
#HiltViewModel
class CountryViewModel #Inject constructor() : BaseViewModel() {
var countryGroupList = flowOf<PagingData<CountryGroup>>()
private val config = PagingConfig(pageSize = 26, prefetchDistance = 1, initialLoadSize = 26)
fun getCountryList() {
countryGroupList = Pager(config) {
CountrySource(api)
}.flow.cachedIn(viewModelScope)
}
}
This is the small package
#Composable
fun SingleRun(onClick: () -> Unit) {
val execute = rememberSaveable { mutableStateOf(true) }
if (execute.value) {
onClick()
execute.value = false
}
}
I don't use Compose much yet, so I could be wrong, but this stood out to me.
I don't think your thread is being blocked. I think you subscribed to an empty flow before replacing it, so there is no data to show.
You shouldn't use a var property for your flow, because the empty original flow could be collected before the new one replaces it. Also, it defeats the purpose of using cachedIn because the flow could be replaced multiple times.
You should eliminate the getCountryList() function and just directly assign the flow. Since it is a cachedIn flow, it doesn't do work until it is first collected anyway. See the documentation:
It won't execute any unnecessary code unless it is being collected.
So your view model should look like:
#HiltViewModel
class CountryViewModel #Inject constructor() : BaseViewModel() {
private val config = PagingConfig(pageSize = 26, prefetchDistance = 1, initialLoadSize = 26)
val countryGroupList = Pager(config) {
CountrySource(api)
}.flow.cachedIn(viewModelScope)
}
}
...and you can remove the SingleRun block from your Composable.
You are not doing anything that would require you to specify dispatchers. The default of Dispatchers.Main is fine here because you are not calling any blocking functions directly anywhere in your code.
I'm building an object detection application (in Kotlin, for Android). The application uses CameraX to build a camera preview and Google ML to provide machine learning expertise. Just for reference; I used this CameraX documentation and this this Google ML Kit documentation.
I'm currently attempting to print Log.d("TAG", "onSuccess" + it.size) to my IDE console in order to determine if .addonSuccessListener is actually running. If it does, it should print something along the lines of onSuccess1. However, this isn't the case. Infact, it isn't even printing the Log statement from the .addOnFailureListener either, which really confuses me as I'm not even entirely sure the objectDetector code is even running. What really puzzles me is that I have relatively completed the same project in Java and have not faced this issue.
I did have someone point out that within my YourImageAnalyzer.kt class, if mediaImage is null, then I won't see anything logging. However, upon my own debugging (this is actually my very first time debugging), I was unable to find out if my first sentence of this paragraph is true or not. I suppose this issue may provide a lead into how I'll resolve this issue, and also learn how to properly debug.
Here is my YourImageAnalyzer.kt class, and I will also add the code for my MainActivity.kt class below as well.
YourImageAnalyzer.kt
private class YourImageAnalyzer : ImageAnalysis.Analyzer {
override fun analyze(imageProxy: ImageProxy) {
val mediaImage = imageProxy.image
if (mediaImage != null) {
val image =
InputImage.fromMediaImage(mediaImage, imageProxy.imageInfo.rotationDegrees)
val localModel = LocalModel.Builder()
.setAssetFilePath("mobilenet_v1_0.75_192_quantized_1_metadata_1.tflite")
.build()
val customObjectDetectorOptions =
CustomObjectDetectorOptions.Builder(localModel)
.setDetectorMode(CustomObjectDetectorOptions.STREAM_MODE)
.enableClassification()
.setClassificationConfidenceThreshold(0.5f)
.setMaxPerObjectLabelCount(3)
.build()
val objectDetector =
ObjectDetection.getClient(customObjectDetectorOptions)
objectDetector //Here is where the issue stems, with the following listeners
.process(image)
.addOnSuccessListener {
Log.i("TAG", "onSuccess" + it.size)
for (detectedObjects in it)
{
val boundingBox = detectedObjects.boundingBox
val trackingId = detectedObjects.trackingId
for (label in detectedObjects.labels) {
val text = label.text
val index = label.index
val confidence = label.confidence
}
}
}
.addOnFailureListener { e -> Log.e("TAG", e.getLocalizedMessage()) }
.addOnCompleteListener { it -> imageProxy.close() }
}
}
}
MainActivity.kt
class MainActivity : AppCompatActivity() {
private lateinit var cameraProviderFuture: ListenableFuture<ProcessCameraProvider>
override fun onCreate(savedInstanceState: Bundle?) {
cameraProviderFuture = ProcessCameraProvider.getInstance(this)
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
cameraProviderFuture.addListener(Runnable {
val cameraProvider = cameraProviderFuture.get()
bindPreview(cameraProvider)
}, ContextCompat.getMainExecutor(this))
}
fun bindPreview(cameraProvider: ProcessCameraProvider) {
val previewView = findViewById<PreviewView>(R.id.previewView)
var preview : Preview = Preview.Builder()
.build()
var cameraSelector : CameraSelector = CameraSelector.Builder()
.requireLensFacing(CameraSelector.LENS_FACING_BACK)
.build()
preview.setSurfaceProvider(previewView.surfaceProvider)
var camera = cameraProvider.bindToLifecycle(this as LifecycleOwner, cameraSelector, preview)
}
}
You are not binding your ImageAnalysis use case. Something in the line of:
val imageAnalysis = ImageAnalysis.Builder()
.setTargetResolution(Size(1280, 720))
.setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
.setOutputImageFormat(ImageAnalysis.OUTPUT_IMAGE_FORMAT_RGBA_8888)
.build()
and then;
imageAnalysis.setAnalyzer(executor, YourImageAnalyzer())
cameraProvider.bindToLifecycle(this as LifecycleOwner, cameraSelector, imageAnalysis, preview)
Also a suggestion as a bonus:
You should get your LocalModel.Builder() out of analyze as this is called each time an image arrives. You do not need to execute this code piece each time as it will make your analysis slower.
So move this code:
val localModel = LocalModel.Builder()
.setAssetFilePath("mobilenet_v1_0.75_192_quantized_1_metadata_1.tflite")
.build()
to just below of the class private class YourImageAnalyzer : ImageAnalysis.Analyzer {.
I am writing a Kotlin app and using Firebase for authentication.
As onActivityResult is now depraceted, I am trying to migrate my app to use registerForActivityResult. I have a link to Google account feature, that starts with the Google sign-in flow, as shown here. My code:
private fun initGoogleSignInClient() =
activity?.let {
// Configure Google Sign In
val gso =
GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
.requestIdToken(getString(R.string.default_web_client_id))
.requestEmail()
.build()
// Build a GoogleSignInClient with the options specified by gso.
viewModel.googleSignInClient = GoogleSignIn.getClient(it, gso)
}
private fun showLinkWithGoogle() =
startActivityForResult(viewModel.googleSignInClient.signInIntent, RC_LINK_GOOGLE)
Where initGoogleSignInClient is called in the fragment's onCreateView, and showLinkWithGoogle is called when the user taps the button on the screen. This workes perfectly.
I looked for an example using registerForActivityResult, and the best one I found was at the bottom of this page. I added this code:
private val linkWithGoogle =
registerForActivityResult(ActivityResultContracts.StartIntentSenderForResult()) {
viewModel.handleGoogleResult(it.data)
}
private fun showLinkWithGoogle() =
linkWithGoogle.launch(IntentSenderRequest.Builder(viewModel.googleSignInClient.signInIntent))
But realized that IntentSenderRequest.Builder needs an IntentSender and not an Intent. I haven't found any example of how to build an IntentSender from an Intent, nor a way to get one from my GoogleSignInClient.
Could anyone please provide a full example of using registerForActivityResult(ActivityResultContracts.StartIntentSenderForResult())?
Thank you very much!
For this use-case, you don't need an ActivityResultContracts of type StartIntentSenderForResult but one of type StartActivityForResult. Here is an example (since you did not provide your full implementation):
Fragment
private val googleRegisterResult =
registerForActivityResult(ActivityResultContracts.StartActivityForResult()) { result ->
result.checkResultAndExecute {
val task = GoogleSignIn.getSignedInAccountFromIntent(data)
val account = task.getResult(ApiException::class.java)
loginViewModel.onEvent(LoginRegistrationEvent.SignInWithGoogle(account))
}.onFailure { e -> toast("Error: ${e.message}") }
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
myGoogleSignInButton.setOnClickListener {
googleRegisterResult.launch(viewModel.googleSignInClient.signInIntent)
}
}
Then, in your viewmodel, you can handle the login as you would usually do, the only difference is, that you no longer need an RC_SIGN_IN
ViewModel Example
class YourViewModel : ViewModel() {
fun onEvent(event: LoginRegistrationEvent) {
when(event) {
is LoginRegistrationEvent.SignInWithGoogle -> {
viewModelScope.launch {
val credential = GoogleAuthProvider.getCredential(event.account.idToken)
Firebase.auth.signInWithCredential(credential).await()
}
}
}
}
}
To make my life easier, I created an extension function, that checks, if the login was successful and then executes a block of code (in this case, getting the account), while caching any exceptions. Futhermore, inside your block, you have access to an instance of ActivityResult as this:
inline fun ActivityResult.checkResultAndExecute(block: ActivityResult.() -> Unit) =
if (resultCode == Activity.RESULT_OK) runCatching(block)
else Result.failure(Exception("Something went wrong"))