Java 在我的应用程序中拍照并将其保存在多媒体资料中

我知道以前有人问过这个问题，但我看过的所有答案都没有给我答案（很可能是因为其中一些我不理解，但也因为似乎有很多不同的解决方案，而且我看不到实情）

我希望通过提供我的代码，有人能为我指明正确的方向

这是我的班级用来拍照的：

public class CameraPhotoActivity extends AppCompatActivity {

private Button btnCapture;
private TextureView textureView;

// to check the state orientation of the output image
private static final SparseIntArray ORIENTATIONS = new SparseIntArray();

static {
    ORIENTATIONS.append(Surface.ROTATION_0, 90);
    ORIENTATIONS.append(Surface.ROTATION_90, 0);
    ORIENTATIONS.append(Surface.ROTATION_180, 270);
    ORIENTATIONS.append(Surface.ROTATION_270, 180);
}

private String cameraId;
private CameraDevice cameraDevice;
private CameraCaptureSession cameraCaptureSessions;
private CaptureRequest.Builder captureRequestBuilder;
private Size imageDimension;
private ImageReader imageReader;

// save to file
private File file;
private static final int REQUEST_CAMERA_PERMISSION = 200;
private boolean mFlashSupported;
private Handler mBackgroundHandler;
private HandlerThread mBackgroundThread;

CameraDevice.StateCallback stateCallback = new CameraDevice.StateCallback() {
    @Override
    public void onOpened(@NonNull CameraDevice camera) {
        cameraDevice = camera;
        createCameraPreview();
    }

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

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


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

    textureView = (TextureView) findViewById(R.id.textureView);
    assert textureView != null;
    textureView.setSurfaceTextureListener(textureListener);
    btnCapture = (Button) findViewById(R.id.btnCapture);
    btnCapture.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            takePicture();
        }
    });
}

private void takePicture() {

    if (cameraDevice == null)
        return;
    CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    try {
        CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraDevice.getId());
        Size[] jpegSizes = null;
        if (characteristics != null)
            jpegSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP)
                    .getOutputSizes(ImageFormat.JPEG);

        // capture the image with custom size
        int width = 640;
        int height = 480;
        if (jpegSizes != null && jpegSizes.length > 0) {
            width = jpegSizes[0].getWidth();
            height = jpegSizes[0].getHeight();
        }
        final ImageReader reader = ImageReader.newInstance(width, height, ImageFormat.JPEG, 1);
        List<Surface> outputSurface = new ArrayList<>(2);
        outputSurface.add(reader.getSurface());
        outputSurface.add(new Surface(textureView.getSurfaceTexture()));

        final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
        captureBuilder.addTarget(reader.getSurface());
        captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);

        // check the orientation on the device
        int rotation = getWindowManager().getDefaultDisplay().getRotation();
        captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation));

        file = new File(Environment.getExternalStorageDirectory() + "/" + UUID.randomUUID().toString()
                + ".jpg");
        ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener() {
            @Override
            public void onImageAvailable(ImageReader imageReader) {
                Image image = null;
                try {
                    image = reader.acquireLatestImage();
                    ByteBuffer buffer = image.getPlanes()[0].getBuffer();
                    byte[] bytes = new byte[buffer.capacity()];
                    buffer.get(bytes);
                    save(bytes);
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                    {
                        if (image != null)
                            image.close();
                    }
                }
            }

            private void save(byte[] bytes) throws IOException {
                OutputStream outputStream = null;
                try {
                    outputStream = new FileOutputStream(file);
                    outputStream.write(bytes);
                } finally {
                    if (outputStream != null)
                        outputStream.close();
                }



            }
        };

        reader.setOnImageAvailableListener(readerListener, mBackgroundHandler);
        final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback() {
            @Override
            public void onCaptureCompleted(@NonNull CameraCaptureSession session, @NonNull CaptureRequest request, @NonNull TotalCaptureResult result) {
                super.onCaptureCompleted(session, request, result);
                Toast.makeText(CameraPhotoActivity.this, "Saved " + file, Toast.LENGTH_SHORT).show();
                createCameraPreview();
            }
        };

        cameraDevice.createCaptureSession(outputSurface, new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                try {
                    cameraCaptureSession.capture(captureBuilder.build(), captureListener, mBackgroundHandler);
                } catch (CameraAccessException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {

            }
        }, mBackgroundHandler);


    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

private void createCameraPreview() {
    try {
        SurfaceTexture texture = textureView.getSurfaceTexture();
        assert texture != null;
        texture.setDefaultBufferSize(imageDimension.getWidth(), imageDimension.getHeight());
        Surface surface = new Surface(texture);
        captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
        captureRequestBuilder.addTarget(surface);
        cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {
                if (cameraDevice == null)
                    return;
                cameraCaptureSessions = cameraCaptureSession;
                updatePreview();
            }

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

private void updatePreview() {
    if (cameraDevice == null)
        Toast.makeText(this, "Error", Toast.LENGTH_SHORT).show();
    captureRequestBuilder.set(CaptureRequest.CONTROL_MODE, CaptureRequest.CONTROL_MODE_AUTO);
    try {
        cameraCaptureSessions.setRepeatingRequest(captureRequestBuilder.build(), null, mBackgroundHandler);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

private void openCamera() {
    CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    try {
        cameraId = manager.getCameraIdList()[0];
        CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId);
        StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
        assert map != null;
        imageDimension = map.getOutputSizes(SurfaceTexture.class)[0];
        // check realtime permission if run higher than API 23
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{
                    Manifest.permission.CAMERA,
                    Manifest.permission.WRITE_EXTERNAL_STORAGE
            }, REQUEST_CAMERA_PERMISSION);
            return;
        }
        manager.openCamera(cameraId, stateCallback, null);

    } catch (CameraAccessException e) {
        e.printStackTrace();
    }
}

TextureView.SurfaceTextureListener textureListener = new TextureView.SurfaceTextureListener() {
    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int i, int i1) {
        openCamera();
    }

    @Override
    public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int i, int i1) {

    }

    @Override
    public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
        return false;
    }

    @Override
    public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {

    }
};

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    if (requestCode == REQUEST_CAMERA_PERMISSION) {
        if (grantResults[0] != PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(this, "You can't use the camera without permission", Toast.LENGTH_SHORT).show();
            finish();
        }
    }
}

@Override
protected void onResume() {
    super.onResume();
    startBackgroundThread();
    if (textureView.isAvailable())
        openCamera();
    else
        textureView.setSurfaceTextureListener(textureListener);
}

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

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

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

谢谢你的帮助。非常感谢。

这是“上下文”的意思。一旦从相机中获取图像，就需要将代码放在activity类中。在调用scanFile之前也要调用connect。您可以尝试下面的代码

MediaScannerConnection.scanFile(CameraPhotoActivity.this, new String[]{file.toString()}, null,
                        new MediaScannerConnection.OnScanCompletedListener() {
                            public void onScanCompleted(String path, Uri uri) {
                                Log.i("External Storage", "Scanned" + path + ":");
                                Log.i("External Storage", "-> uri=" + uri);
                            }
                        });

---

使用上面的代码会出现什么错误？错误的第一个参数类型-它是针对“this”的。我将此代码放在“save”方法下面。这是正确的吗？你能告诉我你在哪一行出错吗？“错误的第一个参数类型”这是以“MediaScannerConnection”开头的代码的第一行。当你看到“this”时，它用红色下划线，悬停在上面会显示“第一个参数类型错误”的消息。你知道吗，当你发布这篇文章时，我正要尝试一下。你刚刚证实了我的想法。这就是为什么我对你的答案投了赞成票，并将其标记为正确。谢谢

MediaScannerConnection.scanFile(CameraPhotoActivity.this, new String[]{file.toString()}, null,
                        new MediaScannerConnection.OnScanCompletedListener() {
                            public void onScanCompleted(String path, Uri uri) {
                                Log.i("External Storage", "Scanned" + path + ":");
                                Log.i("External Storage", "-> uri=" + uri);
                            }
                        });