我想照相机屏幕上的一个具体区域。

我在尝试计算和生产照片时认为,我曾尝试过一些图书馆,但我没有做任何工作,因此我需要你的帮助,因为我 st住这个问题,这样做似乎非常容易,但确实不是。

在此,我XML 我照相活动守则:

<?xml version="1.0" encoding="utf-8"?>
<layout 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">

    <data>

    </data>

    <androidx.constraintlayout.widget.ConstraintLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true">

        <androidx.camera.view.PreviewView
            android:id="@+id/preview_view"
            android:layout_width="0dp"
            android:layout_height="0dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent"
            />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@drawable/transparentbackground"
            android:backgroundTint="#A4686868"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="parent" />

        <ImageView
            android:id="@+id/camera_frame"
            android:layout_width="250dp"
            android:layout_height="250dp"
            android:background="@drawable/ic_camera_frame"
            app:layout_constraintBottom_toTopOf="@+id/image_capture_button"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@+id/preview_view" />

        <SeekBar
            android:id="@+id/zoom_seek_bar"
            android:layout_width="0dp"
            android:visibility="gone"
            android:layout_height="@dimen/seek_bar_height"
            android:layout_marginStart="@dimen/seek_bar_margin"
            android:layout_marginEnd="@dimen/seek_bar_margin"
            android:layout_marginBottom="@dimen/seek_bar_margin"
            app:layout_constraintBottom_toTopOf="@+id/image_capture_button"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent" />

        <FrameLayout
            android:id="@+id/frameLayout"
            android:layout_width="150dp"
            android:layout_height="150dp"
            app:layout_constraintBottom_toTopOf="@+id/image_capture_button"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintStart_toStartOf="parent"
            app:layout_constraintTop_toTopOf="@id/preview_view">

            <SurfaceView
                android:id="@+id/surfaceView"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />

        </FrameLayout>


        <Button
            android:id="@+id/image_capture_button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginEnd="@dimen/capture_btn_end_margin"
            android:layout_marginBottom="24dp"
            android:elevation="2dp"
            android:text="@string/capture"
            android:backgroundTint="@color/main"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent"
            app:layout_constraintLeft_toLeftOf="parent" />

        <ImageButton
            android:id="@+id/closeCamera"
            android:layout_width="50dp"
            android:layout_height="0dp"
            android:layout_marginEnd="10dp"
            android:layout_marginBottom="24dp"
            android:backgroundTint="@color/main"
            android:background="@drawable/cross_close_icon"
            android:elevation="2dp"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintEnd_toEndOf="parent" />

        <ImageButton
            android:id="@+id/switchTextInputButton"
            android:layout_width="48dp"
            android:layout_height="48dp"
            android:layout_marginStart="10dp"
            android:layout_marginBottom="24dp"
            android:background="@drawable/baseline_text_fields_24"
            android:backgroundTint="@color/main"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintStart_toStartOf="parent" />

    </androidx.constraintlayout.widget.ConstraintLayout>

</layout>

并在此附上我的照相活动代码:

class CameraActivity : AppCompatActivity() {

    private lateinit var binding: ActivityCameraBinding
    private var imageCapture: ImageCapture? = null
    private var cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
    private var counter = 0

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityCameraBinding.inflate(layoutInflater)
        setContentView(binding.root)


        binding.imageCaptureButton.setOnClickListener {
            photoCapture()
        }

        binding.switchTextInputButton.setOnClickListener {
            startActivity(Intent(this@CameraActivity, SensorAddManuelActivity::class.java))
        }

        if(allPermissionsGrantedByUser()) {
            Toast.makeText(this,
            "We Have Permission",
            Toast.LENGTH_SHORT).show()
        } else {
            ActivityCompat.requestPermissions(
                this, Constants.REQUIRED_PERMISSIONS,
                Constants.REQUEST_CODE_PERMISSION
            )
        }

        initializeCamera()
        cameraCloseButton()
        hideSystemNavigationBars()
        supportActionBar?.hide()
    }

    override fun onBackPressed() {
        counter++
        if (counter == 1){
            val intent = Intent(this, OpenCameraActivity::class.java)
            startActivity(intent)
        }
    }

    private fun hideSystemNavigationBars() {
        window.decorView.apply {
            systemUiVisibility = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION or View.SYSTEM_UI_FLAG_FULLSCREEN
        }
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<String>,
        grantResults: IntArray) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        if (requestCode == Constants.REQUEST_CODE_PERMISSION){
            if(allPermissionsGrantedByUser()){
                initializeCamera()
            }else{
                Toast.makeText(this,
                    "Permissions not granted by the user.",
                    Toast.LENGTH_SHORT).show()
                finish()
            }
        }
    }

    private fun allPermissionsGrantedByUser() =
        Constants.REQUIRED_PERMISSIONS.all{
            ContextCompat.checkSelfPermission(
                baseContext, it
            ) == PackageManager.PERMISSION_GRANTED
        }

    private fun cameraCloseButton() {
        binding.closeCamera.setOnClickListener{
            startActivity(Intent(this@CameraActivity, OpenCameraActivity::class.java))
        }
    }


    private fun photoCapture() {
        imageCapture ?: return

        val photoFile = File(getExternalFilesDir(Environment.DIRECTORY_PICTURES), SimpleDateFormat("yyyyMMddHHmmSS", Locale.US).format(System.currentTimeMillis()) + ".jpeg")

        val outputOptions = ImageCapture.OutputFileOptions.Builder(photoFile).build()

        imageCapture!!.takePicture(
            outputOptions, ContextCompat.getMainExecutor(this),
            object : ImageCapture.OnImageSavedCallback {
                override fun onError(exc: ImageCaptureException) {
                    try {
                        val savedUri = Uri.fromFile(photoFile)
                        savedUri.path?.let { safePath ->
                            val file = File(safePath)
                            file.delete()
                        }
                    } catch (e: Exception) {
                        e.printStackTrace()
                    }
                    Toast.makeText(
                        this@CameraActivity,
                        "Something went wrong!",
                        Toast.LENGTH_LONG
                    ).show()
                }

                @SuppressLint("RestrictedApi")
                override fun onImageSaved(output: ImageCapture.OutputFileResults) {
                    val savedUri = Uri.fromFile(photoFile)
                    savedUri.path?.let { safePath ->
                        CameraPreviewActivity.path = safePath
                        startActivity(Intent(this@CameraActivity, CameraPreviewActivity::class.java))
                    }
                }
            }
        )
    }

    private fun initializeCamera() {
        val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener({
            val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()
            val preview = Preview.Builder()
                .build()
                .also {
                    it.setSurfaceProvider(binding.previewView.surfaceProvider)
                }
            imageCapture = ImageCapture.Builder()
                .build()
            try {
                cameraProvider.unbindAll()
                val camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview, imageCapture)
                val cameraControl = camera.cameraControl
                val cameraInfo = camera.cameraInfo
                cameraTouchControls(cameraControl, cameraInfo)
                sliderBarZoomFeature(cameraControl)
            } catch(e: Exception) {
                e.printStackTrace()
            }
        }, ContextCompat.getMainExecutor(this))
    }

    private fun cameraTouchControls(cameraControl: CameraControl, cameraInfo: CameraInfo) {
        val listener = object : ScaleGestureDetector.SimpleOnScaleGestureListener() {

            override fun onScale(detector: ScaleGestureDetector): Boolean {

                val currentZoomRatio = cameraInfo.zoomState.value?.zoomRatio ?: 0F

                binding.zoomSeekBar.progress = currentZoomRatio.toInt()

                val delta = detector.scaleFactor

                cameraControl.setZoomRatio(currentZoomRatio * delta)

                return true
            }
        }

        val scaleGestureDetector = ScaleGestureDetector(baseContext, listener)

        binding.previewView.setOnTouchListener { _, event ->
            scaleGestureDetector.onTouchEvent(event)
            if (event.action == MotionEvent.ACTION_DOWN) {
                val factory = binding.previewView.meteringPointFactory
                val point = factory.createPoint(event.x, event.y)
                val action = FocusMeteringAction.Builder(point, FocusMeteringAction.FLAG_AF)
                    .setAutoCancelDuration(5, TimeUnit.SECONDS)
                    .build()
                cameraControl.startFocusAndMetering(action)
            }
            true
        }
    }

    private fun sliderBarZoomFeature(cameraControl: CameraControl) {
        val zoomSlider = findViewById<SeekBar>(R.id.zoom_seek_bar)
        zoomSlider.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {
            override fun onProgressChanged(seekBar: SeekBar?, progress: Int, fromUser: Boolean) {
                cameraControl.setLinearZoom(progress / 100.toFloat())
            }

            override fun onStartTrackingTouch(seekBar: SeekBar?) {}

            override fun onStopTrackingTouch(seekBar: SeekBar?) {}
        })
    }

}