前言：
实现拍照功能的主要步骤：
- 创建照相机对象
- 设置相机参数
- 对照片预览
- 照片拍摄 获取照相机所得到的图片数据，从而可以进行下一步的活动，例如保存到本地存储，进行数据压缩，通过可视化组件显示。
- 停止照相
首先是布局页面activity_camera_demo.xml，用户点击进来后，通过设置完相应的参数后，对摄像头得到照片进行预览，通过TextureView实现
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout 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=".CameraDemoActivity"> <TextureView android:id="@+id/textureView" android:layout_width="match_parent" android:layout_height="match_parent" /> <Button android:id="@+id/btn_photo" android:layout_width="70dp" android:layout_height="70dp" android:layout_alignParentBottom="true" android:layout_centerHorizontal="true" android:layout_marginBottom="50dp" android:text="拍照" /> </RelativeLayout>
对应的CameraDemoActivity类实现拍照，并保存到本地的功能
public class CameraDemoActivity extends AppCompatActivity { private TextureView textureView; private HandlerThread handlerThread; private Handler mCameraHandler; private CameraManager cameraManager; //最佳的预览尺寸 private Size previewSize; //最佳的拍照尺寸 private Size mCaptureSize; private String mCameraId; private CameraDevice cameraDevice; private CaptureRequest.Builder captureRequestBuilder; private CaptureRequest captureRequest; private CameraCaptureSession mCameraCaptureSession; private Button btn_photo; private ImageReader imageReader; private static final SparseArray ORIENTATION = new SparseArray(); static { ORIENTATION.append(Surface.ROTATION_0, 90); ORIENTATION.append(Surface.ROTATION_90, 0); ORIENTATION.append(Surface.ROTATION_180, 270); ORIENTATION.append(Surface.ROTATION_270, 180); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_camera_demo); textureView = findViewById(R.id.textureView); btn_photo = findViewById(R.id.btn_photo); btn_photo.setOnClickListener(OnClick); } private final View.OnClickListener OnClick = new View.OnClickListener() { @Override public void onClick(View v) { //获取摄像头的请求 try { CaptureRequest.Builder cameraDeviceCaptureRequest = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE); cameraDeviceCaptureRequest.addTarget(imageReader.getSurface()); //获取摄像头的方向 int rotation = getWindowManager().getDefaultDisplay().getRotation(); CameraCaptureSession.CaptureCallback mCaptureCallback = new CameraCaptureSession.CaptureCallback() { @Override public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) { super.onCaptureCompleted(session, request, result); Toast.makeText(CameraDemoActivity.this, "拍照结束，相片已保存！", Toast.LENGTH_SHORT).show(); unLockFocus(); } }; //设置拍照方向 cameraDeviceCaptureRequest.set(CaptureRequest.JPEG_ORIENTATION, (Integer) ORIENTATION.get(rotation)); mCameraCaptureSession.stopRepeating(); mCameraCaptureSession.capture(cameraDeviceCaptureRequest.build(), mCaptureCallback, mCameraHandler); } catch (CameraAccessException e) { e.printStackTrace(); } //获取图像的缓冲区 //获取文件的存储权限及操作 } }; private void unLockFocus() { captureRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL); try { mCameraCaptureSession.setRepeatingRequest(captureRequestBuilder.build(), null, mCameraHandler); } catch (CameraAccessException e) { e.printStackTrace(); } } @Override protected void onResume() { super.onResume(); startCameraThread(); if (!textureView.isAvailable()) { textureView.setSurfaceTextureListener(mTextureListener); } else { startPreview(); } } TextureView.SurfaceTextureListener mTextureListener = new TextureView.SurfaceTextureListener() { @Override public void onSurfaceTextureAvailable(@NonNull SurfaceTexture surface, int width, int height) { //SurfaceTexture组件可用的时候,设置相机参数，并打开摄像头 //设置摄像头参数 setUpCamera(width, height); //打开摄像头 openCamera(); } @Override public void onSurfaceTextureSizeChanged(@NonNull SurfaceTexture surface, int width, int height) { //尺寸发生变化的时候 } @Override public boolean onSurfaceTextureDestroyed(@NonNull SurfaceTexture surface) { //组件被销毁的时候 return false; } @Override public void onSurfaceTextureUpdated(@NonNull SurfaceTexture surface) { //组件更新的时候 } }; private void setUpCamera(int width, int height) { cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE); //拿到摄像头的id try { for (String cameraId : cameraManager.getCameraIdList()) { //得到摄像头的参数 CameraCharacteristics cameraCharacteristics = cameraManager.getCameraCharacteristics(cameraId); Integer facing = cameraCharacteristics.get(CameraCharacteristics.LENS_FACING); if (facing != null && facing == CameraCharacteristics.LENS_FACING_FRONT) { continue; } StreamConfigurationMap map = cameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP); if (map != null) { //找到摄像头能够输出的，最符合我们当前屏幕能显示的最小分辨率 previewSize = getOptimalSize(map.getOutputSizes(SurfaceTexture.class), width, height); mCaptureSize = Collections.max(Arrays.asList(map.getOutputSizes(ImageFormat.JPEG)), new Comparator<Size>() { @Override public int compare(Size o1, Size o2) { return Long.signum(o1.getWidth() * o1.getHeight() - o2.getWidth() * o2.getHeight()); } }); } //建立ImageReader准备存储照片 setUpImageReader(); mCameraId = cameraId; break; } } catch (CameraAccessException e) { e.printStackTrace(); } } private void setUpImageReader() { imageReader = ImageReader.newInstance(mCaptureSize.getWidth(), mCaptureSize.getHeight(), ImageFormat.JPEG, 2); imageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() { @Override public void onImageAvailable(ImageReader reader) { mCameraHandler.post(new ImageSaver(reader.acquireNextImage())); } }, mCameraHandler); } //存储图片的过程 private class ImageSaver implements Runnable { private Image image; public ImageSaver(Image image) { this.image = image; } @Override public void run() { ByteBuffer byteBuffer = image.getPlanes()[0].getBuffer(); byte[] data = new byte[byteBuffer.remaining()]; byteBuffer.get(data); // String path =getFilesDir(); String path = Environment.getExternalStorageDirectory() + "/DCIM/CameraV2/"; File file = new File(path); //判断当前的文件目录是否存在，如果不存在就创建这个文件目录 if (!file.exists()) { file.mkdir(); } String timeStamp = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()); String fileName = "IMG_" + timeStamp + ".jpg"; FileOutputStream fileOutputStream = null; try { fileOutputStream = new FileOutputStream(fileName); fileOutputStream.write(data, 0, data.length); } catch (IOException e) { e.printStackTrace(); } finally { if (fileOutputStream != null) { try { fileOutputStream.close(); } catch (IOException e) { e.printStackTrace(); } } } } } //得到最佳的预览尺寸 private Size getOptimalSize(Size[] outputSizes, int width, int height) { ArrayList<Size> arrayList = new ArrayList<>(); for (Size option : outputSizes) { if (width > height) { //横屏 if (option.getWidth() > width && option.getHeight() > height) { arrayList.add(option); } } else { //竖屏 if (option.getWidth() > height && option.getHeight() > width) { arrayList.add(option); } } } if (arrayList.size() > 1) { return Collections.min(arrayList, new Comparator<Size>() { @Override public int compare(Size o1, Size o2) { return Long.signum(o1.getWidth() * o1.getHeight() - o2.getWidth() * o2.getHeight()); } }); } return outputSizes[0]; } private void openCamera() { if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) { ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1); return; } try { cameraManager.openCamera(mCameraId, mStateCallback, mCameraHandler); } catch (CameraAccessException e) { e.printStackTrace(); } } CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() { @Override public void onOpened(@NonNull CameraDevice camera) { //摄像头打开 cameraDevice = camera; startPreview(); } @Override public void onDisconnected(@NonNull CameraDevice camera) { //摄像头关闭 cameraDevice.close(); cameraDevice = null; } @Override public void onError(@NonNull CameraDevice camera, int error) {//摄像头出现错误 cameraDevice.close(); cameraDevice = null; } }; //开始预览 private void startPreview() { //建立图像缓冲区 SurfaceTexture surfaceTexture = textureView.getSurfaceTexture(); surfaceTexture.setDefaultBufferSize(previewSize.getWidth(), previewSize.getHeight()); //得到界面的显示对象 Surface surface = new Surface(surfaceTexture); try { captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW); captureRequestBuilder.addTarget(surface); //建立通道(CaptureRequest和CaptureSession会话) cameraDevice.createCaptureSession(Arrays.asList(surface, imageReader.getSurface()), new CameraCaptureSession.StateCallback() { @Override public void onConfigured(@NonNull CameraCaptureSession session) { captureRequest = captureRequestBuilder.build(); mCameraCaptureSession = session; try { mCameraCaptureSession.setRepeatingRequest(captureRequest, null, mCameraHandler); } catch (CameraAccessException e) { e.printStackTrace(); } } @Override public void onConfigureFailed(@NonNull CameraCaptureSession session) { } }, mCameraHandler); } catch (CameraAccessException e) { e.printStackTrace(); } } //开启摄像头线程 private void startCameraThread() { handlerThread = new HandlerThread("myHandlerThread"); handlerThread.start(); mCameraHandler = new Handler(handlerThread.getLooper()); } }
代码有点多，但是注释已经在代码中给出，大家可以体会一下，其中的用法，根据自己的需求封装该功能~
