안드로이드 Camera2 API 예제 및 설명

안드로이드 5.0 이상의 버전은 Camera API 대신 Camera2 API를 사용할 수 있다. 

이 코드는 안드로이드 6.0에서도 사용이 가능하도록 하였다.

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public class MainActivity extends AppCompatActivity {
    private TextureView mCameraTextureView;
    private Preview mPreview;

    Activity mainActivity = this;

    private static final String TAG = "MAINACTIVITY";

    static final int REQUEST_CAMERA = 1;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mCameraTextureView = (TextureView) findViewById(R.id.cameraTextureView);
        mPreview = new Preview(this, mCameraTextureView);

    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case REQUEST_CAMERA:
                for (int i = 0; i < permissions.length; i++) {
                    String permission = permissions[i];
                    int grantResult = grantResults[i];
                    if (permission.equals(Manifest.permission.CAMERA)) {
                        if(grantResult == PackageManager.PERMISSION_GRANTED) {
                            mCameraTextureView = (TextureView) findViewById(R.id.cameraTextureView);
                            mPreview = new Preview(mainActivity, mCameraTextureView);
                            Log.d(TAG,"mPreview set");
                        } else {
                            Toast.makeText(this,"Should have camera permission to run", Toast.LENGTH_LONG).show();
                            finish();
                        }
                    }
                }
                break;
        }
    }

    @Override
    protected void onResume() {
        super.onResume();
        mPreview.onResume();
    }

    @Override
    protected void onPause() {
        super.onPause();
        mPreview.onPause();
    }
}

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위는 이코드의  MainActivity이다. 카메라의 화면을 보여주는 TextureView와 카메라의 기능을 하는 Preview를 선언하였다.

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public class Preview extends Thread {
    private final static String TAG = "Preview : ";

    private Size mPreviewSize;
    private Context mContext;
    private CameraDevice mCameraDevice;
    private CaptureRequest.Builder mPreviewBuilder;
    private CameraCaptureSession mPreviewSession;
    private TextureView mTextureView;

    public Preview(Context context, TextureView textureView) {
        mContext = context;
        mTextureView = textureView;
    }

    private String getBackFacingCameraId(CameraManager cManager) {
        try {
            for (final String cameraId : cManager.getCameraIdList()) {
                CameraCharacteristics characteristics = cManager.getCameraCharacteristics(cameraId);
                int cOrientation = characteristics.get(CameraCharacteristics.LENS_FACING);
                if (cOrientation == CameraCharacteristics.LENS_FACING_BACK) return cameraId;
            }
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
        return null;
    }

    public void openCamera() {
        CameraManager manager = (CameraManager) mContext.getSystemService(Context.CAMERA_SERVICE);
        Log.e(TAG, "openCamera E");
        try {
            String cameraId = getBackFacingCameraId(manager);
            CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
            StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
            mPreviewSize = map.getOutputSizes(SurfaceTexture.class)[0];

            int permissionCamera = ContextCompat.checkSelfPermission(mContext, Manifest.permission.CAMERA);
            if(permissionCamera == PackageManager.PERMISSION_DENIED) {
                ActivityCompat.requestPermissions((Activity) mContext, new String[]{Manifest.permission.CAMERA}, MainActivity.REQUEST_CAMERA);
            } else {
                manager.openCamera(cameraId, mStateCallback, null);
            }
        } catch (CameraAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        Log.e(TAG, "openCamera X");
    }

    private TextureView.SurfaceTextureListener mSurfaceTextureListener = new TextureView.SurfaceTextureListener(){

        @Override
        public void onSurfaceTextureAvailable(SurfaceTexture surface,
                                              int width, int height) {
            // TODO Auto-generated method stub
            Log.e(TAG, "onSurfaceTextureAvailable, width="+width+",height="+height);
            openCamera();
        }

        @Override
        public void onSurfaceTextureSizeChanged(SurfaceTexture surface,
                                                int width, int height) {
            // TODO Auto-generated method stub
            Log.e(TAG, "onSurfaceTextureSizeChanged");
        }

        @Override
        public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
            // TODO Auto-generated method stub
            return false;
        }

        @Override
        public void onSurfaceTextureUpdated(SurfaceTexture surface) {
            // TODO Auto-generated method stub
        }
    };

    private CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {

        @Override
        public void onOpened(CameraDevice camera) {
            // TODO Auto-generated method stub
            Log.e(TAG, "onOpened");
            mCameraDevice = camera;
            startPreview();
        }

        @Override
        public void onDisconnected(CameraDevice camera) {
            // TODO Auto-generated method stub
            Log.e(TAG, "onDisconnected");
        }

        @Override
        public void onError(CameraDevice camera, int error) {
            // TODO Auto-generated method stub
            Log.e(TAG, "onError");
        }

    };

    protected void startPreview() {
        // TODO Auto-generated method stub
        if(null == mCameraDevice || !mTextureView.isAvailable() || null == mPreviewSize) {
            Log.e(TAG, "startPreview fail, return");
        }

        SurfaceTexture texture = mTextureView.getSurfaceTexture();
        if(null == texture) {
            Log.e(TAG,"texture is null, return");
            return;
        }

        texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
        Surface surface = new Surface(texture);

        try {
            mPreviewBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        } catch (CameraAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        mPreviewBuilder.addTarget(surface);

        try {
            mCameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {

                @Override
                public void onConfigured(CameraCaptureSession session) {
                    // TODO Auto-generated method stub
                    mPreviewSession = session;
                    updatePreview();
                }

                @Override
                public void onConfigureFailed(CameraCaptureSession session) {
                    // TODO Auto-generated method stub
                    Toast.makeText(mContext, "onConfigureFailed", Toast.LENGTH_LONG).show();
                }
            }, null);
        } catch (CameraAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    protected void updatePreview() {
        // TODO Auto-generated method stub
        if(null == mCameraDevice) {
            Log.e(TAG, "updatePreview error, return");
        }

        mPreviewBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
        HandlerThread thread = new HandlerThread("CameraPreview");
        thread.start();
        Handler backgroundHandler = new Handler(thread.getLooper());

        try {
            mPreviewSession.setRepeatingRequest(mPreviewBuilder.build(), null, backgroundHandler);
        } catch (CameraAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public void setSurfaceTextureListener()
    {
        mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
    }

    public void onResume() {
        Log.d(TAG, "onResume");
        setSurfaceTextureListener();
    }

    private Semaphore mCameraOpenCloseLock = new Semaphore(1);

    public void onPause() {
        // TODO Auto-generated method stub
        Log.d(TAG, "onPause");
        try {
            mCameraOpenCloseLock.acquire();
            if (null != mCameraDevice) {
                mCameraDevice.close();
                mCameraDevice = null;
                Log.d(TAG, "CameraDevice Close");
            }
        } catch (InterruptedException e) {
            throw new RuntimeException("Interrupted while trying to lock camera closing.");
        } finally {
            mCameraOpenCloseLock.release();
        }
    }
}

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Camera2 API는 기존의 Camera API와 다르게 선언해야하는 여러가지 Camera 클래스들이 있다.

CameraDevice는 카메라 기기를 나타내고 CameraManager는 카메라의 기능을 시키는 요소이다.

카메라를 켜기위해 openCamera를 사용하였는데

이 함수는 SurfaceTextureListener내부의 onSurfaceTextureAvailable에 위치한다

TextureView가 사용이 가능하다면 카메라를 켜는 기능이다.

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public void openCamera() {
    CameraManager manager = (CameraManager) mContext.getSystemService(Context.CAMERA_SERVICE);
    Log.e(TAG, "openCamera E");
    try {
        String cameraId = getBackFacingCameraId(manager);
        CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
        StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
        mPreviewSize = map.getOutputSizes(SurfaceTexture.class)[0];

        int permissionCamera = ContextCompat.checkSelfPermission(mContext, Manifest.permission.CAMERA);
        if(permissionCamera == PackageManager.PERMISSION_DENIED) {
            ActivityCompat.requestPermissions((Activity) mContext, new String[]{Manifest.permission.CAMERA}, MainActivity.REQUEST_CAMERA);
        } else {
            manager.openCamera(cameraId, mStateCallback, null);
        }
    } catch (CameraAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    Log.e(TAG, "openCamera X");
}

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또한 카메라를 다시 켜고 싶다면, SurfaceTextureListener만 다시 선언해 주면 된다.

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public void setSurfaceTextureListener()
{
    mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
}

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카메라가 켜진다면 카메라 상태 콜백함수가 실행된다.

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private CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {

    @Override
    public void onOpened(CameraDevice camera) {
        // TODO Auto-generated method stub
        Log.e(TAG, "onOpened");
        mCameraDevice = camera;
        startPreview();
    }

    @Override
    public void onDisconnected(CameraDevice camera) {
        // TODO Auto-generated method stub
        Log.e(TAG, "onDisconnected");
    }

    @Override
    public void onError(CameraDevice camera, int error) {
        // TODO Auto-generated method stub
        Log.e(TAG, "onError");
    }

};

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이 함수 내부에 onOpened함수가 있는데 카메라가 켜지면 자동적으로 실행된다. 

여기서 실질적으로 하는 함수는 startPreview함수이다.

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protected void startPreview() {
    // TODO Auto-generated method stub
    if(null == mCameraDevice || !mTextureView.isAvailable() || null == mPreviewSize) {
        Log.e(TAG, "startPreview fail, return");
    }

    SurfaceTexture texture = mTextureView.getSurfaceTexture();
    if(null == texture) {
        Log.e(TAG,"texture is null, return");
        return;
    }

    texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());
    Surface surface = new Surface(texture);

    try {
        mPreviewBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
    } catch (CameraAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    mPreviewBuilder.addTarget(surface);

    try {
        mCameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {

            @Override
            public void onConfigured(CameraCaptureSession session) {
                // TODO Auto-generated method stub
                mPreviewSession = session;
                updatePreview();
            }

            @Override
            public void onConfigureFailed(CameraCaptureSession session) {
                // TODO Auto-generated method stub
                Toast.makeText(mContext, "onConfigureFailed", Toast.LENGTH_LONG).show();
            }
        }, null);
    } catch (CameraAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

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startPreview함수는 위와 같다. 여기서는 카메라의 출력을 어디로 보낼 것인지 설정한다.

출력은 최대 3개까지 지정할 수 있다.

여기서는 카메라 프리뷰만 설정하였는데, 사진촬영 동영상촬영은 이 함수 내에 코드를 몇개만 바꿔서 사용할 수 있다.

카메라의 출력은 surface로 저장되어 mPreviewBuilder에 들어가게 된다. 

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protected void updatePreview() {
    // TODO Auto-generated method stub
    if(null == mCameraDevice) {
        Log.e(TAG, "updatePreview error, return");
    }

    mPreviewBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
    HandlerThread thread = new HandlerThread("CameraPreview");
    thread.start();
    Handler backgroundHandler = new Handler(thread.getLooper());

    try {
        mPreviewSession.setRepeatingRequest(mPreviewBuilder.build(), null, backgroundHandler);
    } catch (CameraAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

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마지막으로 updatePreview함수가 실행된다.

이 함수는 화면의 프리뷰를 계속 변경시켜주는 Thread를 실행시키는 함수이다.

이것으로 카메라의 프리뷰가 실행된다.

아래는 Camera2 API를 이해하기 위해 코드이다.

Camera2Raw : https://github.com/googlesamples/android-Camera2Raw

예제로 사용한 코드는 GitHub에 업로드 하였다.

mapp : https://github.com/pchan1401-ICIL/mapp