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如何才能像camera api中的PreviewCallback和camerax中的ImageAnalysis.Analyzer一样,在android studio中获取camera2接口中的每一帧?

在Android Studio中获取Camera2接口中的每一帧,可以通过以下步骤实现:

  1. 首先,确保你的应用程序具有相机权限。在AndroidManifest.xml文件中添加相机权限声明:
代码语言:txt
复制
<uses-permission android:name="android.permission.CAMERA" />
  1. 创建一个相机管理类,用于打开相机和设置相机参数。可以使用CameraManager类来实现这一点。以下是一个简单的相机管理类示例:
代码语言:txt
复制
import android.content.Context;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CaptureRequest;
import android.hardware.camera2.params.StreamConfigurationMap;
import android.util.Size;
import android.view.Surface;

import java.util.Arrays;

public class CameraHelper {
    private CameraDevice cameraDevice;
    private CaptureRequest.Builder captureRequestBuilder;
    private CameraCaptureSession cameraCaptureSession;

    public void openCamera(Context context, String cameraId, Surface surface) {
        CameraManager cameraManager = (CameraManager) context.getSystemService(Context.CAMERA_SERVICE);
        try {
            cameraManager.openCamera(cameraId, new CameraDevice.StateCallback() {
                @Override
                public void onOpened(CameraDevice camera) {
                    cameraDevice = camera;
                    createCaptureSession(surface);
                }

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

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

    private void createCaptureSession(Surface surface) {
        try {
            captureRequestBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
            captureRequestBuilder.addTarget(surface);

            cameraDevice.createCaptureSession(Arrays.asList(surface), new CameraCaptureSession.StateCallback() {
                @Override
                public void onConfigured(CameraCaptureSession session) {
                    cameraCaptureSession = session;
                    startPreview();
                }

                @Override
                public void onConfigureFailed(CameraCaptureSession session) {
                    // Configuration failed
                }
            }, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    private void startPreview() {
        try {
            cameraCaptureSession.setRepeatingRequest(captureRequestBuilder.build(), null, null);
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
    }

    public void closeCamera() {
        if (cameraCaptureSession != null) {
            cameraCaptureSession.close();
            cameraCaptureSession = null;
        }

        if (cameraDevice != null) {
            cameraDevice.close();
            cameraDevice = null;
        }
    }
}
  1. 在你的Activity或Fragment中,使用CameraHelper类来打开相机并获取每一帧。以下是一个简单的示例:
代码语言:txt
复制
import android.Manifest;
import android.content.pm.PackageManager;
import android.graphics.ImageFormat;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraManager;
import android.os.Bundle;
import android.util.Size;
import android.view.Surface;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;

public class MainActivity extends AppCompatActivity implements SurfaceHolder.Callback {
    private static final int REQUEST_CAMERA_PERMISSION = 200;

    private SurfaceView surfaceView;
    private SurfaceHolder surfaceHolder;
    private CameraHelper cameraHelper;

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

        surfaceView = findViewById(R.id.surfaceView);
        surfaceHolder = surfaceView.getHolder();
        surfaceHolder.addCallback(this);

        cameraHelper = new CameraHelper();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        cameraHelper.closeCamera();
    }

    @Override
    public void surfaceCreated(@NonNull SurfaceHolder holder) {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, REQUEST_CAMERA_PERMISSION);
        } else {
            openCamera();
        }
    }

    @Override
    public void surfaceChanged(@NonNull SurfaceHolder holder, int format, int width, int height) {
        // Surface changed
    }

    @Override
    public void surfaceDestroyed(@NonNull SurfaceHolder holder) {
        // Surface destroyed
    }

    private void openCamera() {
        CameraManager cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
        try {
            String cameraId = cameraManager.getCameraIdList()[0];
            CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(cameraId);
            Size[] outputSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP).getOutputSizes(SurfaceHolder.class);
            Size previewSize = outputSizes[0]; // Choose the desired preview size

            surfaceHolder.setFixedSize(previewSize.getWidth(), previewSize.getHeight());

            Surface surface = surfaceHolder.getSurface();
            cameraHelper.openCamera(this, cameraId, surface);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

在上述示例中,我们使用CameraHelper类打开相机并将预览输出到SurfaceView上。你可以根据需要自定义SurfaceView的布局和样式。

请注意,这只是一个简单的示例,你可能需要根据你的具体需求进行更多的定制和错误处理。此外,还可以使用ImageReader类来获取相机每一帧的数据。

希望这能帮助到你!

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