Android Camera2 拍照——使用TextureView

与天地兮比寿，与日月兮齐光。这篇文章主要讲述Android Camera2 拍照——使用TextureView相关的知识，希望能为你提供帮助。
原文:Android Camera2 拍照（二）——使用TextureView【Android Camera2 拍照——使用TextureView】上一篇博文简单介绍了使用Camera2 API拍摄照片，并使用SurfaceView作为预览界面。实际上，相对于SurfaceView, TextureView更适合用于视频和拍摄照片。SurfaceView也有它的使用场合，这将在另外一篇中阐述。本文将使用TextureView作为预览界面，再次向大家展示Camera2 API的简单应用。
1，定义TextureView作为预览界面在布局文件中加入TextureView控件，然后实现其监听事件

textureView = (TextureView) findViewById(R.id.textureView);
然后我们可以在OnResume()方法中设置监听SurefaceTexture的事件

textureView.setSurfaceTextureListener(textureListener);

当SurefaceTexture准备好后会回调SurfaceTextureListener 的onSurfaceTextureAvailable()方法

private TextureView.SurfaceTextureListener mTextureListener = new TextureView.SurfaceTextureListener() { @Override public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) { //当SurefaceTexture可用的时候，设置相机参数并打开相机 setupCamera(width, height); openCamera(); }@Override public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {}@Override public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) { return false; }@Override public void onSurfaceTextureUpdated(SurfaceTexture surface) {} };

2，设置相机参数

private void setupCamera(int width, int height) { //获取摄像头的管理者CameraManager CameraManager manager = (CameraManager) getContext().getSystemService(Context.CAMERA_SERVICE); try { //遍历所有摄像头 for (String cameraId : manager.getCameraIdList()) { CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId); Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING); //此处默认打开后置摄像头 if (facing != null & & facing == CameraCharacteristics.LENS_FACING_FRONT) continue; //获取StreamConfigurationMap，它是管理摄像头支持的所有输出格式和尺寸 StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP); assert map != null; //根据TextureView的尺寸设置预览尺寸 mPreviewSize = getOptimalSize(map.getOutputSizes(SurfaceTexture.class), width, height); //获取相机支持的最大拍照尺寸 mCaptureSize = Collections.max(Arrays.asList(map.getOutputSizes(ImageFormat.JPEG)), new Comparator< Size> () { @Override public int compare(Size lhs, Size rhs) { return Long.signum(lhs.getWidth() * lhs.getHeight() - rhs.getHeight() * rhs.getWidth()); } }); //此ImageReader用于拍照所需 setupImageReader(); mCameraId = cameraId; break; } } catch (CameraAccessException e) { e.printStackTrace(); } }

//选择sizeMap中大于并且最接近width和height的size private Size getOptimalSize(Size[] sizeMap, int width, int height) { List< Size> sizeList = new ArrayList< > (); for (Size option : sizeMap) { if (width > height) { if (option.getWidth() > width & & option.getHeight() > height) { sizeList.add(option); } } else { if (option.getWidth() > height & & option.getHeight() > width) { sizeList.add(option); } } } if (sizeList.size() > 0) { return Collections.min(sizeList, new Comparator< Size> () { @Override public int compare(Size lhs, Size rhs) { return Long.signum(lhs.getWidth() * lhs.getHeight() - rhs.getWidth() * rhs.getHeight()); } }); } return sizeMap[0]; }

private void setupImageReader() { //2代表ImageReader中最多可以获取两帧图像流 mImageReader = ImageReader.newInstance(mCaptureSize.getWidth(), mCaptureSize.getHeight(), ImageFormat.JPEG, 1); mImageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() { @Override public void onImageAvailable(ImageReader reader) { final Image image = reader.acquireNextImage(); mCameraHandler.post(new imageSaver(image)); getActivity().runOnUiThread(new Runnable() { @Override public void run() { ByteBuffer buffer = image.getPlanes()[0].getBuffer(); byte[] bytes = new byte[buffer.remaining()]; buffer.get(bytes); //由缓冲区存入字节数组 final Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length); if (bitmap != null) { ivShow.setImageBitmap(bitmap); } } }); } }, mCameraHandler); }

public static class imageSaver implements Runnable {private Image mImage; public imageSaver(Image image) { mImage = image; }@Override public void run() { ByteBuffer buffer = mImage.getPlanes()[0].getBuffer(); byte[] data = https://www.songbingjia.com/android/new byte[buffer.capacity()]; buffer.get(data); String path = Environment.getExternalStorageDirectory() +"/DCIM/361camera/"; File mImageFile = new File(path); if (!mImageFile.exists()) { boolean ret = mImageFile.mkdirs(); assert (ret); } String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date()); String fileName = path + "IMG_" + timeStamp + ".jpg"; FileOutputStream fos = null; try { fos = new FileOutputStream(fileName); fos.write(data, 0, data.length); } catch (IOException e) { e.printStackTrace(); } finally { if (fos != null) { try { fos.close(); } catch (IOException e) { e.printStackTrace(); } } mImage.close(); } } }

3，开启相机

private void openCamera() { mCameraManager = (CameraManager) getContext().getSystemService(Context.CAMERA_SERVICE); try { if (ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) { //申请WRITE_EXTERNAL_STORAGE权限 requestPermissions(new String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_CODE); //return; } else { mCameraManager.openCamera(mCameraId, mStateCallback, mCameraHandler); } } catch (CameraAccessException e) { e.printStackTrace(); } }

实现StateCallback 接口，当相机打开后会回调onOpened方法，在这个方法里面开启预览

private CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() { @Override public void onOpened(CameraDevice camera) { mCameraDevice = camera; startPreview(); }@Override public void onDisconnected(CameraDevice camera) { camera.close(); mCameraDevice = null; }@Override public void onError(CameraDevice camera, int error) { camera.close(); mCameraDevice = null; } };

4，开启相机预览

private void startPreview() { SurfaceTexture mSurfaceTexture = mTextureView.getSurfaceTexture(); mSurfaceTexture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight()); Surface previewSurface = new Surface(mSurfaceTexture); try { mCaptureRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW); mCaptureRequestBuilder.addTarget(previewSurface); mCameraDevice.createCaptureSession(Arrays.asList(previewSurface, mImageReader.getSurface()), new CameraCaptureSession.StateCallback() { @Override public void onConfigured(CameraCaptureSession session) { try { mCaptureRequest = mCaptureRequestBuilder.build(); mCameraCaptureSession = session; mCameraCaptureSession.setRepeatingRequest(mCaptureRequest, null, mCameraHandler); } catch (CameraAccessException e) { e.printStackTrace(); } }@Override public void onConfigureFailed(CameraCaptureSession session) {} }, mCameraHandler); } catch (CameraAccessException e) { e.printStackTrace(); } }

5，实现PreviewCallback首先创建一个ImageReader，并监听它的事件（见上面的代码setupImageReader()）。然后开启预览之前，设置ImageReader为输出Surface（见上面setupCamera()的代码）。
6，拍照

public void takePicture() { lockFocus(); }private void lockFocus() { try { mCaptureRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START); mCameraCaptureSession.capture(mCaptureRequestBuilder.build(), mCaptureCallback, mCameraHandler); } catch (CameraAccessException e) { e.printStackTrace(); } }