Errors in connection of CameraFragment.kt with xml - kotlin

Question

I need help please, i'm getting errors in fragment.kt in process of getting a camera set up
**
//fragmentcamera.xml
**
**<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.camera.view.PreviewView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/preview"/>
<Button
android:id="#+id/btnTakePhoto"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:text="Take photo"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toStartOf="#id/btnDisplayGallery"
app:layout_constraintBottom_toBottomOf="parent"/>
<Button
android:id="#+id/btnDisplayGallery"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="16dp"
android:layout_marginBottom="300dp"
android:text="Display gallery"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#id/btnTakePhoto" />
</androidx.constraintlayout.widget.ConstraintLayout>**
The following are images for camerafragment.kt
s
the errors that i am getting

Answer 1

import android.Manifest
import android.content.Intent
import android.content.pm.PackageManager
import android.graphics.Color
import android.graphics.drawable.ColorDrawable
import android.os.Bundle
import android.util.Log
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Button
import android.widget.Toast
import androidx.camera.core.CameraSelector
import androidx.camera.core.ImageCapture
import androidx.camera.core.ImageCaptureException
import androidx.camera.core.Preview
import androidx.camera.lifecycle.ProcessCameraProvider
import androidx.camera.view.PreviewView
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import androidx.core.net.toUri
import androidx.fragment.app.Fragment
import com.google.common.util.concurrent.ListenableFuture
import java.io.File
import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors
class cameraFragment : Fragment() {
// TODO: Rename and change types of parameters
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
//ListenableFuture interface listens for async operations external to
// main thread
// requires type of activity being observed - ProcessCameraProvider
private lateinit var cameraProviderFuture:
ListenableFuture<ProcessCameraProvider>
//used to decide whether to use front or back camera
private lateinit var cameraSelector: CameraSelector
//use case for capturing images
private var imageCapture: ImageCapture? = null
//interface that extends Executor to provide thread for capturing an image
private lateinit var imgCaptureExecutor: ExecutorService
//static variables
companion object {
//used for messages output in debugger
val TAG = "cameraFragment"
//used to check request code
private var REQUEST_CODE = 101
}
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View {
// Inflate the layout for requireActivity() fragment
val view: View = inflater.inflate(
R.layout.xml_camera,
container,
false
)
//get instance of ProcessCameraProvider
cameraProviderFuture = ProcessCameraProvider.getInstance(requireActivity())
//set default to back camera
cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
//instantiate imgCaptureExecutor
imgCaptureExecutor = Executors.newSingleThreadExecutor()
//check for permissions (similar to other sensors)
if (ActivityCompat.checkSelfPermission(
requireActivity(),
Manifest.permission.CAMERA
) != PackageManager.PERMISSION_GRANTED
)
//request permissions
ActivityCompat.requestPermissions(
requireActivity(),
arrayOf(
//array containing required permissions
Manifest.permission.CAMERA
),
REQUEST_CODE
)
else {
//if permission already granted, start camera
startCamera()
}
//set up event listener for btnCapture click
val btnTakePhoto: Button = view.findViewById(R.id.btnTakePhoto)
btnTakePhoto.setOnClickListener {
takePhoto()
} //set up event listener for btnGallery click
val btnDisplayGallery: Button = view.findViewById(R.id.btnDisplayGallery)
btnDisplayGallery.setOnClickListener {
displayGallery()
}
return view
}
//invoked when permissions change
override fun onRequestPermissionsResult(
requestCode: Int,
permissions: Array<out String>,
grantResults: IntArray
) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults)
//check that request code matches and permission granted
if (requestCode == REQUEST_CODE &&
grantResults.isNotEmpty() &&
grantResults[0] == PackageManager.PERMISSION_GRANTED
) {
//if permission now granted, start camera
startCamera()
}
}
//listen for data from camera
private fun startCamera() {
cameraProviderFuture.addListener(
{
//create ProcessCameraProvider instance
val cameraProvider = cameraProviderFuture.get()
//connect preview use case to the preview in the xml file
val preview: PreviewView = requireView().findViewById(R.id.preview)
val previewCase = Preview.Builder().build().also {
it.setSurfaceProvider(preview.surfaceProvider)
}
//instantiate capture use case
imageCapture = ImageCapture.Builder().build()
try {
//clear all bindings to previous use cases first
cameraProvider.unbindAll()
//bind lifecycle of camera to lifecycle of application
cameraProvider.bindToLifecycle(
requireActivity(),
cameraSelector, previewCase
)
cameraProvider.bindToLifecycle(
requireActivity(), cameraSelector,
imageCapture
)
} catch (e: Exception) {
Log.d(TAG, "Use case binding failed")
}
},
//run asynchronous operation being listened to by cameraProviderFuture
ContextCompat.getMainExecutor(requireActivity())
)
}
//take photo
private fun takePhoto() {
imageCapture?.let {
//create file with fileName using timestamped in milliseconds
val file = File(
requireActivity().externalMediaDirs[0],
"snap_${System.currentTimeMillis()}"
)
//save image in above file
val outputFileOptions =
ImageCapture.OutputFileOptions.Builder(file).build()
//call takePicture method with where to find image
it.takePicture(
outputFileOptions,
imgCaptureExecutor,
//set up callbacks for when picture is taken
object : ImageCapture.OnImageSavedCallback {
override fun onImageSaved(
outputFileResults:
ImageCapture.OutputFileResults
) {
Log.i(TAG, "Image saved in ${file.toUri()}")
}
override fun onError(exception: ImageCaptureException) {
Toast.makeText(
requireActivity(),
"Error taking photo",
Toast.LENGTH_LONG
).show()
Log.i(TAG, "Error taking photo: $exception")
}
}
)
}
animateFlash()
}
//flash to provide feedback that photo taken
private fun animateFlash() {
val preview: PreviewView = requireView().findViewById(R.id.preview)
preview.postDelayed({
preview.foreground = ColorDrawable(Color.argb(125, 255, 255, 255))
preview.postDelayed({
preview.foreground = null
}, 30)
}, 60)
}
//display gallery
private fun displayGallery() {
val intent = Intent(requireActivity(), GalleryActivity::class.java)
startActivity(intent)
}
}

Answer 2

Replace all "this,getApplicationContext" with getActivity(). In Java
Replace all "this,getApplicationContext" with activity. In Kotlin.
Two likely definitions:
getActivity() in a Fragment returns the Activity the Fragment is currently associated with. (see http://developer.android.com/reference/android/app/Fragment.html#getActivity()).
getActivity() is user-defined.