Android 使用 CameraX 實現拍照和錄制視頻 - 扣丁書屋

AndroidX是Jetpack包下的組件，谷歌幫你考慮好了很多細節，用就完事了。這些細節想自己設置的話也可以，不設置使用默認值照樣很舒服。

導包

implementation "androidx.camera:camera-camera2:1.0.0-beta07"
implementation "androidx.camera:camera-view:1.0.0-alpha14"
implementation "androidx.camera:camera-extensions:1.0.0-alpha14"
implementation "androidx.camera:camera-lifecycle:1.0.0-beta07"

請求權限

在 Manifest 的 manifest 節點下中加入以下內容：

<!--攝像頭權限-->
<uses-permission android:name="android.permission.CAMERA" />
<!--具備攝像頭-->
<uses-feature android:name="android.hardware.camera.any" />
<!--存儲圖像或者視頻權限-->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<!--錄制音頻權限-->
<uses-permission android:name="android.permission.RECORD_AUDIO" />

Android Q適配

在 manifest 標簽里面加入一條屬性：

 android:requestLegacyExternalStorage="true"

畫黃線不理，如果不加這句，在Android Q上會無法往相冊存儲文件。

創建預覽布局

這里參考官方Demo的寫法，最底部圖層是一個PreviewView用來預覽，上層放兩個按鈕，一個用來拍照，一個用來錄像。

<?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">

    <Button
        android:id="@+id/btnStartVideo"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:layout_marginBottom="50dp"
        android:elevation="2dp"
        android:scaleType="fitCenter"
        android:text="Start Video"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@id/camera_capture_button" />

    <Button
        android:id="@+id/camera_capture_button"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:elevation="2dp"
        android:scaleType="fitCenter"
        android:text="Take Photo"
        app:layout_constraintBottom_toBottomOf="@+id/btnStartVideo"
        app:layout_constraintEnd_toStartOf="@id/btnStartVideo"
        app:layout_constraintStart_toStartOf="parent" />

    <androidx.camera.view.PreviewView
        android:id="@+id/viewFinder"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

Activity中申請權限

聲明權限列表

companion object {
    private const val REQUEST_CODE_PERMISSIONS = 10
    private val REQUIRED_PERMISSIONS = arrayOf(Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE,
                Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.RECORD_AUDIO)
}

判斷當前是否已有權限的方法

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

在 onCreate 里開始主要邏輯。如果已有權限，開啟相機預覽。

 if (allPermissionsGranted()) {
      startCamera()
} else {
      ActivityCompat.requestPermissions(this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS)
}

在請求權限返回的時候，判斷是否已有權限，如果有了就可以開啟預覽了

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

聲明全局變量

private lateinit var cameraExecutor: ExecutorService
var cameraProvider: ProcessCameraProvider? = null//相機信息
var preview: Preview? = null//預覽對象
var cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA//當前相機
var camera: Camera? = null//相機對象
private var imageCapture: ImageCapture? = null//拍照用例
var videoCapture: VideoCapture? = null//錄像用例

開啟相機預覽

開啟預覽，把預覽內容放進 PreviewView 里。

    private fun startCamera() {
        cameraExecutor = Executors.newSingleThreadExecutor()
        val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener(Runnable {
            cameraProvider = cameraProviderFuture.get()//獲取相機信息

            //預覽配置
            preview = Preview.Builder()
                    .build()
                    .also {
                        it.setSurfaceProvider(viewFinder.createSurfaceProvider())
                    }

            imageCapture = ImageCapture.Builder().build()//拍照用例配置

            val imageAnalyzer = ImageAnalysis.Builder()
                    .build()
                    .also {
                        it.setAnalyzer(cameraExecutor, LuminosityAnalyzer { luma ->
                            Log.d(TAG, "Average luminosity: $luma")
                        })
                    }

            cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA//使用后置攝像頭
            videoCapture = VideoCapture.Builder()//錄像用例配置
//                .setTargetAspectRatio(AspectRatio.RATIO_16_9) //設置高寬比
//                .setTargetRotation(viewFinder.display.rotation)//設置旋轉角度
//                .setAudioRecordSource(AudioSource.MIC)//設置音頻源麥克風
                    .build()

            try {
                cameraProvider?.unbindAll()//先解綁所有用例
                camera = cameraProvider?.bindToLifecycle(this, cameraSelector, preview, imageCapture, videoCapture)//綁定用例
            } catch (exc: Exception) {
                Log.e(TAG, "Use case binding failed", exc)
            }

        }, ContextCompat.getMainExecutor(this))
    }

監聽，寫在Activity外面

typealias LumaListener = (luma: Double) -> Unit

再在Activity里面寫一個內部類

private class LuminosityAnalyzer(private val listener: LumaListener) : ImageAnalysis.Analyzer {

        private fun ByteBuffer.toByteArray(): ByteArray {
            rewind()
            val data = ByteArray(remaining())
            get(data)
            return data
        }

        override fun analyze(image: ImageProxy) {

            val buffer = image.planes[0].buffer
            val data = buffer.toByteArray()
            val pixels = data.map { it.toInt() and 0xFF }
            val luma = pixels.average()

            listener(luma)

            image.close()
        }
    }

界面銷毀時關閉線程

override fun onDestroy() {
    super.onDestroy()
    cameraExecutor.shutdown()
}

拍照方法

private fun takePhoto() {
    val imageCapture = imageCapture ?: return
    val file = File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM).path +
            "/CameraX" + SimpleDateFormat(FILENAME_FORMAT, Locale.CHINA).format(System.currentTimeMillis()) + ".jpg")
    val outputOptions = ImageCapture.OutputFileOptions.Builder(file).build()
    imageCapture.takePicture(outputOptions, ContextCompat.getMainExecutor(this),
            object : ImageCapture.OnImageSavedCallback {
                override fun onError(exc: ImageCaptureException) {
                    Log.e(TAG, "Photo capture failed: ${exc.message}", exc)
                }
                override fun onImageSaved(output: ImageCapture.OutputFileResults) {
                    val savedUri = Uri.fromFile(file)
                    val msg = "Photo capture succeeded: $savedUri"
                    Toast.makeText(baseContext, msg, Toast.LENGTH_SHORT).show()
                    Log.d(TAG, msg)
                }
            })
}

錄像方法

private fun takeVideo() {
    //視頻保存路徑
    val file = File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM).path + "/CameraX" + SimpleDateFormat(
            FILENAME_FORMAT, Locale.CHINA
    ).format(System.currentTimeMillis()) + ".mp4")
    //開始錄像
    videoCapture?.startRecording(file, Executors.newSingleThreadExecutor(), object : OnVideoSavedCallback {
        override fun onVideoSaved(@NonNull file: File) {
            //保存視頻成功回調，會在停止錄制時被調用
            Toast.makeText(this@MainActivity, file.absolutePath, Toast.LENGTH_SHORT).show()
        }
        override fun onError(videoCaptureError: Int, message: String, cause: Throwable?) {
            //保存失敗的回調，可能在開始或結束錄制時被調用
            Log.e("", "onError: $message")
        }
    })


    btnStartVideo.setOnClickListener {
        //結束錄像
        videoCapture?.stopRecording()//停止錄制
        preview?.clear()//清除預覽
        btnStartVideo.text = "Start Video"
        btnStartVideo.setOnClickListener {
            btnStartVideo.text = "Stop Video"
            takeVideo()
        }
        Toast.makeText(this, file.path, Toast.LENGTH_SHORT).show()
        Log.d("path", file.path)
    }
}

文中代碼完整Demo

Github CameraX-Demo https://github.com/DubheBroken/CameraX-Demo

參考文章：

Google CameraX 開發文檔掘金-JetPack之使用CameraX完成拍照和拍視頻 Stackoverflow-Exception 'open failed: EACCES (Permission denied)' on Android

https://mp.weixin.qq.com/s/B7VVEZ7LWr_XDCApcRtUTg