如何给 PreviewView 拍照？

Question

基本上当用户点击takePicture按钮时我想对当前previewView拍照。

这是我的 startCamera 方法：


private fun startCamera() {

        val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener(Runnable {
            val cameraProvider = cameraProviderFuture.get()
            preview = Preview.Builder().build()
            preview?.setSurfaceProvider(findViewById<PreviewView>(R.id.cameraView).createSurfaceProvider(camera?.cameraInfo))
            imageCapture = ImageCapture.Builder().build()
            val cameraSelector = CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build()
            cameraProvider.unbindAll()

            camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview, imageCapture)
        }, ContextCompat.getMainExecutor(this))
    }

和拍照：


private fun takePicture() {


//this is where I want to take a picture and then save it in the gallery



        val intentTour = Intent(this@MainActivity, MainActivity_eredmenyek::class.java)
        intentTour.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP)
        startActivity(intentTour)
    }

Answer 1

看This

 val imageCapture = ImageCapture.Builder()
            .setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
            // We request aspect ratio but no resolution to match preview config, but letting
            // CameraX optimize for whatever specific resolution best fits our use cases
            .setTargetAspectRatio(screenAspectRatio)
            // Set initial target rotation, we will have to call this again if rotation changes
            // during the lifecycle of this use case
            .setTargetRotation(rotation)
            .build()

 cameraProvider.bindToLifecycle(
                this, cameraSelector, preview, imageCapture, imageAnalyzer)

imageCapture?.let { imageCapture ->

                // Create output file to hold the image
                val photoFile = createFile(outputDirectory, FILENAME, PHOTO_EXTENSION)

                // Setup image capture metadata
                val metadata = Metadata().apply {

                    // Mirror image when using the front camera
                    isReversedHorizontal = lensFacing == CameraSelector.LENS_FACING_FRONT
                }

                // Create output options object which contains file + metadata
                val outputOptions = ImageCapture.OutputFileOptions.Builder(photoFile)
                    .setMetadata(metadata)
                    .build()

                // Setup image capture listener which is triggered after photo has been taken
                imageCapture.takePicture(
                    outputOptions, cameraExecutor, object : ImageCapture.OnImageSavedCallback {
                        override fun onError(exc: ImageCaptureException) {
                            val message = "Photo capture failed: ${exc.message}"

                            Log.e(TAG, message, exc)


                            exc.printStackTrace()
                        }

                        override fun onImageSaved(output: ImageCapture.OutputFileResults) {
                            val savedUri = output.savedUri ?: Uri.fromFile(photoFile)
                            Log.d(TAG, "Photo capture succeeded: $savedUri")

                            // Implicit broadcasts will be ignored for devices running API level >= 24
                            // so if you only target API level 24+ you can remove this statement
                            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N) {
                                requireActivity().sendBroadcast(
                                    Intent(android.hardware.Camera.ACTION_NEW_PICTURE, savedUri)
                                )
                            }

                            // If the folder selected is an external media directory, this is
                            // unnecessary but otherwise other apps will not be able to access our
                            // images unless we scan them using [MediaScannerConnection]
                            val mimeType = MimeTypeMap.getSingleton()
                                .getMimeTypeFromExtension(savedUri.toFile().extension)
                            val uriImage = savedUri.toFile().absolutePath
                            MediaScannerConnection.scanFile(
                                context,
                                arrayOf(uriImage),
                                arrayOf(mimeType)
                            ) { _, uri ->
                                Log.d(TAG, "Image capture scanned into media store: $uri")
                            }
                        }
                    })
            }

如何给 PreviewView 拍照？

How to take picture of a PreviewView?

camera

android

kotlin