CameraPermissions.kt

class ClassicficationActivity : AppCompatActivity() {
    
    private val REQUEST_CAMERA_CODE = 13
    private val PERMISSIONS = arrayOf(Manifest.permission.CAMERA)
    
    private val executor = Executors.newSingleThreadExecutor()

    private var textResult1: TextView? = null
    private var textResult2: TextView? = null
    private var textResult3: TextView? = null

    private lateinit var viewFinder: TextureView

    private var imageClassifier:ImageClassifier? = null

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        
        
        
        viewFinder = findViewById(R.id.view_finder)
        imageClassifier = ImageClassifier(this)
        
        if (allPermissionsGranted()) {
            viewFinder.post { startCamera() }
        }else {
            ActivityCompat.requestPermissions(
                this, PERMISSIONS, REQUEST_CAMERA_CODE
            )
        }

    // Process result from permission request dialog and 
    // if request has been granted start camera
    // else show permission not granted
    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        if (requestCode == REQUEST_CAMERA_CODE && grantResults.isNotEmpty() 
            && grantResults[0] == PackageManager.PERMISSION_GRANTED
        ) {
            if (allPermissionsGranted()) {
                viewFinder.post { startCamera() }
            } else {
                Toast.makeText(this, "Permissions not granted", Toast.LENGTH_LONG)
                    .show()
                finish()
            }
        }
    }

    // check if camera permission specified in the manifest has been granted
    private fun allPermissionsGranted() = PERMISSIONS.all {
        ContextCompat.checkSelfPermission(
            baseContext, it
        ) == PackageManager.PERMISSION_GRANTED
    }
}