camera api2拍照步骤与完整demo,包括xml

好的，下面是Camera API2拍照的步骤及完整demo，包括xml:

1. 在AndroidManifest.xml中添加相机权限：

<uses-permission android:name="android.permission.CAMERA" />

2. 在布局文件中添加SurfaceView：

<SurfaceView
    android:id="@+id/surface_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

3. 在Activity中获取相机权限和初始化Camera2：

public class CameraActivity extends AppCompatActivity {

    private static final int REQUEST_CAMERA_PERMISSION = 1;

    private SurfaceView mSurfaceView;
    private CameraManager mCameraManager;
    private CameraDevice mCameraDevice;
    private CameraCaptureSession mCaptureSession;
    private CaptureRequest.Builder mPreviewRequestBuilder;
    private CaptureRequest mPreviewRequest;
    private ImageReader mImageReader;
    private HandlerThread mBackgroundThread;
    private Handler mBackgroundHandler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera);
        mSurfaceView = findViewById(R.id.surface_view);
        mCameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
        if (checkSelfPermission(Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSION);
        } else {
            openCamera();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (requestCode == REQUEST_CAMERA_PERMISSION) {
            if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                openCamera();
            } else {
                Toast.makeText(this, "Camera permission denied", Toast.LENGTH_SHORT).show();
                finish();
            }
        }
    }

    private void openCamera() {
        try {
            mCameraManager.openCamera("0", new CameraDevice.StateCallback() {
                @Override
                public void onOpened(@NonNull CameraDevice cameraDevice) {
                    mCameraDevice = cameraDevice;
                    startPreview();
                }

                @Override
                public void onDisconnected(@NonNull CameraDevice cameraDevice) {
                    cameraDevice.close();
                    mCameraDevice = null;
                }

                @Override
                public void onError(@NonNull CameraDevice cameraDevice, int i) {
                    cameraDevice.close();
                    mCameraDevice = null;
                }
            }, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    private void startPreview() {
        SurfaceHolder surfaceHolder = mSurfaceView.getHolder();
        surfaceHolder.setKeepScreenOn(true);
        surfaceHolder.addCallback(new SurfaceHolder.Callback() {
            @Override
            public void surfaceCreated(SurfaceHolder holder) {
                try {
                    mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
                    mPreviewRequestBuilder.addTarget(holder.getSurface());
                    mCameraDevice.createCaptureSession(Arrays.asList(holder.getSurface(), mImageReader.getSurface()), new CameraCaptureSession.StateCallback() {
                        @Override
                        public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                            mCaptureSession = cameraCaptureSession;
                            try {
                                mPreviewRequest = mPreviewRequestBuilder.build();
                                mCaptureSession.setRepeatingRequest(mPreviewRequest, null, mBackgroundHandler);
                            } catch (CameraAccessException e) {
                                e.printStackTrace();
                            }
                        }

                        @Override
                        public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {
                            Toast.makeText(CameraActivity.this, "Configuration failed", Toast.LENGTH_SHORT).show();
                        }
                    }, null);
                } catch (CameraAccessException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

            }

            @Override
            public void surfaceDestroyed(SurfaceHolder holder) {

            }
        });
    }

    private void takePicture() {
        try {
            CaptureRequest.Builder captureBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
            captureBuilder.addTarget(mImageReader.getSurface());
            captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
            int rotation = getWindowManager().getDefaultDisplay().getRotation();
            captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation));
            CameraCaptureSession.CaptureCallback captureCallback = new CameraCaptureSession.CaptureCallback() {
                @Override
                public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
                    super.onCaptureCompleted(session, request, result);
                    Toast.makeText(CameraActivity.this, "Image saved", Toast.LENGTH_SHORT).show();
                    startPreview();
                }
            };
            mCaptureSession.stopRepeating();
            mCaptureSession.abortCaptures();
            mCaptureSession.capture(captureBuilder.build(), captureCallback, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    private void initializeImageReader() {
        mImageReader = ImageReader.newInstance(mSurfaceView.getWidth(), mSurfaceView.getHeight(), ImageFormat.JPEG, 1);
        mImageReader.setOnImageAvailableListener(new ImageReader.OnImageAvailableListener() {
            @Override
            public void onImageAvailable(ImageReader reader) {
                saveImage(reader.acquireNextImage());
            }
        }, null);
    }

    private void saveImage(Image image) {
        ByteBuffer buffer = image.getPlanes()[0].getBuffer();
        byte[] bytes = new byte[buffer.remaining()];
        buffer.get(bytes);
        FileOutputStream output = null;
        try {
            File file = new File(getExternalFilesDir(null), "pic.jpg");
            output = new FileOutputStream(file);
            output.write(bytes);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            image.close();
            if (null != output) {
                try {
                    output.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    private void startBackgroundThread() {
        mBackgroundThread = new HandlerThread("CameraBackground");
        mBackgroundThread.start();
        mBackgroundHandler = new Handler(mBackgroundThread.getLooper());
    }

    private void stopBackgroundThread() {
        mBackgroundThread.quitSafely();
        try {
            mBackgroundThread.join();
            mBackgroundThread = null;
            mBackgroundHandler = null;
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        startBackgroundThread();
        if (mSurfaceView.isAvailable()) {
            initializeImageReader();
            openCamera();
        } else {
            mSurfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
                @Override
                public void surfaceCreated(SurfaceHolder holder) {
                    initializeImageReader();
                    openCamera();
                }

                @Override
                public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

                }

                @Override
                public void surfaceDestroyed(SurfaceHolder holder) {

                }
            });
        }
    }

    @Override
    protected void onPause() {
        stopBackgroundThread();
        if (mCameraDevice != null) {
            mCameraDevice.close();
            mCameraDevice = null;
        }
        super.onPause();
    }
}

以上就是Camera API2拍照的步骤及完整demo，包括xml。