预览摄像头画面

从最简单的预览摄像头图像开始,我们逐步了解使用方式,代码如下:

布局要求使用 PreviewView,作为SurfaceProvider

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

class CameraXActivity : AppCompatActivity() {
    private val TAG = CameraXActivity::class.java.simpleName
private lateinit var mPreviewView: PreviewView

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_camera_x2)
        mPreviewView = findViewById(R.id.previewView)
        startCameraPreview()
     * 开始相机预览
    private fun startCameraPreview() {
        val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener(Runnable {
            //用于将相机的生命周期绑定到生命周期所有者
            val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()
            //创建预览
            val preview = Preview.Builder().build()
            //选择后置摄像头
            val cameraSelector = CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build()
            try {
                //在重新绑定之前取消绑定
                cameraProvider.unbindAll()
                //将生命周期,选择摄像头,预览,绑定到相机
                val camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview)
                //设置预览的View
                preview.setSurfaceProvider(mPreviewView.createSurfaceProvider(camera.cameraInfo))
            } catch (exc: Exception) {
                Log.e(TAG, "Use case binding failed", exc)
        }, ContextCompat.getMainExecutor(this))
特别简单就完成了,而且无需考虑摄像头的释放
class CameraXActivity : AppCompatActivity() {
    private val TAG = CameraXActivity::class.java.simpleName
    private lateinit var mImageCapture: ImageCapture
    private lateinit var mImageAnalysis: ImageAnalysis
    private lateinit var mPreviewView: PreviewView
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_camera_x2)
        mPreviewView = findViewById(R.id.previewView)
        startCameraPreview()
        takePhoto.setOnClickListener {
            //点击后拍照
            takePhoto()
     * 开始相机预览
    private fun startCameraPreview() {
        val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
        cameraProviderFuture.addListener(Runnable {
            val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()
            val preview = Preview.Builder().build()
            //创建图像捕捉
            mImageCapture = ImageCapture.Builder().build()
            val cameraSelector = CameraSelector.Builder().requireLensFacing(CameraSelector.LENS_FACING_BACK).build()
            try {
                cameraProvider.unbindAll()
                //请注意,这里新增了一个ImageCapture
                val camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview, mImageCapture)
                preview.setSurfaceProvider(mPreviewView.createSurfaceProvider(camera.cameraInfo))
            } catch (exc: Exception) {
                Log.e(TAG, "Use case binding failed", exc)
        }, ContextCompat.getMainExecutor(this))
    private fun takePhoto() {
        //图像的保存路径与名称
        val photoFile = File(applicationContext.externalCacheDir?.path
                , SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault()).format(System.currentTimeMillis()) + ".jpg")
        // 创建图像文件输出选项
        val outputOptions = ImageCapture.OutputFileOptions.Builder(photoFile).build()
        //拍照,并且注册拍照后的结果监听
        mImageCapture.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(photoFile)
                val msg = "Photo capture succeeded: $savedUri"
                Toast.makeText(baseContext, msg, Toast.LENGTH_SHORT).show()
                Log.d(TAG, msg)
拍照图像旋转
代码的其他部分与上面的示例代码一致, 我们只需要关注ImageCapture的创建与添加setTargetRotation
    private fun createImageCapture():ImageCapture{
        //创建图像捕捉
        mImageCapture = ImageCapture.Builder()
                .setTargetRotation(Surface.ROTATION_90)//设置旋转角度,并且只能有4个旋转方向属性ROTATION_0/ROTATION_90/ROTATION_180/ROTATION_270
                .build()
        return mImageCapture
设置执行IO线程
    private fun createImageCapture():ImageCapture{
        //创建图像捕捉
        mImageCapture = ImageCapture.Builder()
                .setIoExecutor(Executors.newSingleThreadExecutor())//设置执行IO线程
                .build()
        return mImageCapture
设置捕捉模式
    private fun createImageCapture():ImageCapture{
        //创建图像捕捉
        mImageCapture = ImageCapture.Builder()
                //CAPTURE_MODE_MAXIMIZE_QUALITY 高画质
                //CAPTURE_MODE_MINIMIZE_LATENCY 低延迟
                .setCaptureMode(ImageCapture.CAPTURE_MODE_MAXIMIZE_QUALITY)
                .build()
        return mImageCapture
设置闪光灯
    private fun createImageCapture():ImageCapture{
        //创建图像捕捉
        mImageCapture = ImageCapture.Builder()
                //FLASH_MODE_ON 闪光灯开启
                //FLASH_MODE_OFF 闪光灯关闭
                //FLASH_MODE_AUTO 闪光灯自动
                .setFlashMode(ImageCapture.FLASH_MODE_ON)
                .build()
        return mImageCapture
设置宽高比
    private fun createImageCapture():ImageCapture{
        mImageCapture = ImageCapture.Builder()
                //RATIO_4_3   4比3
                //RATIO_16_9  16比9
                .setTargetAspectRatio(AspectRatio.RATIO_16_9)
                .build()
        return mImageCapture
设置分辨率
下面还帖了一些注释,这注释的意思是,你可以随便设置分辨率大小,但是真正的分辨率并不一定是你设置的数值,而是在摄像头里获取的分辨率列表中去取最近似值.
为什么会有这种说明? 我这里给没有接触过摄像头开发的朋友说明一下:
手机的摄像头的分辨率并不是可以随便设置的,这需要取决于你开发的设备的摄像头驱动的分辨率列表. 在以往开发Camera1和Camera2的时候我们需要自己获取这份列表,从中选择我们需要的分辨率. 在使用CameraX的时候他们帮我们简化了这个筛选过程,你只需要设置目标分辨率,代码会自动选择近似分辨率
    private fun createImageCapture(): ImageCapture {
        mImageCapture = ImageCapture.Builder()
                目标分辨率尝试建立图像分辨率的最小界限。实际图像分辨率将是尺寸上最接近的可用分辨率，该分辨率不小于由相机实现确定的目标分辨率。
                但是，如果不存在等于或大于目标分辨率的分辨率，则将选择最接近的小于目标分辨率的可用分辨率。
                与提供的 {@link Size} 具有相同纵横比的分辨率将在不同纵横比的分辨率之前优先考虑。
                .setTargetResolution(Size(1280, 720))
                .build()
        return mImageCapture
val factory = SurfaceOrientedMeteringPointFactory(width, height)
val point = factory.createPoint(x, y)
val action = FocusMeteringAction.Builder(point, FocusMeteringAction.FLAG_AF)
    .addPoint(point2, FocusMeteringAction.FLAG_AE) // could have many
    // auto calling cancelFocusAndMetering in 5 seconds
    .setAutoCancelDuration(5, TimeUnit.SECONDS)
    .build()
val future = cameraControl.startFocusAndMetering(action)
future.addListener( Runnable {
    val result = future.get()
    // process the result
} , executor)
   private void takeVideo() {
        VideoCapture videoCapture = new VideoCaptureConfig.Builder()
                //设置宽高
                .setTargetAspectRatio(aspectRatio(width, height))
                //设置旋转角度
                .setTargetRotation(previewView.getDisplay().getRotation())
                .build();
        //录像前必须解绑
        cameraProvider.unbindAll();
        //开启相机预览
        preview.setSurfaceProvider(previewView.createSurfaceProvider());
        //绑定生命周期，这里如果没有参数preview，则只录像，不显示画面
        cameraProvider.bindToLifecycle(this, cameraSelector,preview, videoCapture);
        //视频路径
        File file = getFile(".mp4");
        //开始录像
        videoCapture.startRecording(file, ContextCompat.getMainExecutor(MainActivity.this), new VideoCapture.OnVideoSavedCallback() {
            @Override
            public void onVideoSaved(@NonNull File file) {
                Toast.makeText(MainActivity.this, file.getAbsolutePath(), Toast.LENGTH_SHORT).show();
            @Override
            public void onError(int videoCaptureError, @NonNull String message, @Nullable Throwable cause) {
                Log.d(TAG, "onError: " + message);
        //停止录像，并且回调OnVideoSavedCallback
        btn4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                videoCapture.stopRecording();
                preview.clear();
val imageAnalysis = ImageAnalysis.Builder()
    .setTargetResolution(Size(1280, 720))
    .setBackpressureStrategy(ImageAnalysis.STRATEGY_KEEP_ONLY_LATEST)
    .build()
imageAnalysis.setAnalyzer(Executors.newSingleThreadExecutor(), ImageAnalysis.Analyzer { image ->
    val rotationDegrees = image.imageInfo.rotationDegrees //旋转角度
    val format = image.format //格式
    val width = image.width //宽
    val height = image.height //高
    val plane = image.planes[0] //PlaneProxy数据
    val buffer = plane.buffer
    Log.e("ytzn", "rotationDegrees = $rotationDegrees")
    Log.e("ytzn", "format = $format")
    Log.e("ytzn", "width = $width")
    Log.e("ytzn", "height = $height")
    // insert your code here.
cameraProvider.bindToLifecycle(this as LifecycleOwner, cameraSelector, imageAnalysis, preview)
CameraX 会生成 YUV_420_888 格式的图片 在ImageFormat类里可以看到此格式
    private fun setPreviewExtender(builder: Preview.Builder, cameraSelector: CameraSelector) {
        val extender = AutoPreviewExtender.create(builder)
        //自动模式
        if (extender.isExtensionAvailable(cameraSelector)) {
            extender.enableExtension(cameraSelector)
        //散景扩展
        val bokehPreviewExtender = BokehPreviewExtender.create(builder)
        if (bokehPreviewExtender.isExtensionAvailable(cameraSelector)) {
            bokehPreviewExtender.enableExtension(cameraSelector)
        //hdr扩展
        val hdrPreviewExtender = HdrPreviewExtender.create(builder)
        if (hdrPreviewExtender.isExtensionAvailable(cameraSelector)) {
            hdrPreviewExtender.enableExtension(cameraSelector)
        //美颜模式
        val beautyPreviewExtender = BeautyPreviewExtender.create(builder)
        if (beautyPreviewExtender.isExtensionAvailable(cameraSelector)) {
            beautyPreviewExtender.enableExtension(cameraSelector)
        //夜晚模式
        val nightPreviewExtender = NightPreviewExtender.create(builder)
        if (nightPreviewExtender.isExtensionAvailable(cameraSelector)) {
            nightPreviewExtender.enableExtension(cameraSelector)
CameraX的一些问题
个人在开发过程中发现了一些问题,如下:
1.CameraX不支持外置摄像头
2.一直没找到跟Camera2一样配置摄像头拍照参数的方式
    本文来自博客园，作者：观心静 ，转载请注明原文链接：https://www.cnblogs.com/guanxinjing/p/15132909.html 
    本文版权归作者和博客园共有，欢迎转载，但必须给出原文链接，并保留此段声明，否则保留追究法律责任的权利。