（安卓）【學習記錄】camera2 textureView預覽的簡單封裝。包含imagereader讀取幀數據，直接複製就能用

創建一個 CameraProvider類

package com.example.opencv_cpp_test;

import android.Manifest;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.ImageFormat;
import android.graphics.Matrix;
import android.graphics.RectF;
import android.graphics.SurfaceTexture;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
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.media.Image;
import android.media.ImageReader;
import android.os.Handler;
import android.os.HandlerThread;
import android.util.Log;
import android.util.Size;
import android.view.Surface;
import android.view.TextureView;

import java.nio.ByteBuffer;
import java.util.Arrays;

import static androidx.core.content.ContextCompat.checkSelfPermission;


public class CameraProvider {
    private Activity mContext;
    private String mCameraId;
    private Handler mCameraHandler;
    private CameraDevice mCameraDevice;
    private TextureView mTextureView;
    private CaptureRequest.Builder mPreviewBuilder;
    private Size previewSize;

    ImageReader mImageReader;
    private ImageReader.OnImageAvailableListener mOnImageAvailableListener = new ImageReader.OnImageAvailableListener() {
        @Override
        public void onImageAvailable(ImageReader reader) {
//獲取最新的一幀的Image
            Image image = reader.acquireLatestImage();
            Log.e("cam123","onImageAvailable");
            if(image!=null){

                image.close();
            }
        }
    };

    public CameraProvider(Activity mContext) {
        this.mContext = mContext;
        //創建了一個Thread來供Camera運行使用，使用HandlerThread而不使用Thread是因爲HandlerThread給我們創建了Looper，不用我們自己創建了。
        HandlerThread handlerThread = new HandlerThread("camera");
        handlerThread.start();
        mCameraHandler = new Handler(handlerThread.getLooper());
    }

    public void initTexture(TextureView textureView) {
        mTextureView = textureView;

        textureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
            @Override
            public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
                openCamera(width, height);
            }

            @Override
            public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
            }

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

            @Override
            public void onSurfaceTextureUpdated(SurfaceTexture surface) {
            }
        });
    }
    private void configureTransform(int viewWidth, int viewHeight) {

        int rotation = Surface.ROTATION_90;
        Matrix matrix = new Matrix();
        RectF viewRect = new RectF(0, 0, viewWidth, viewHeight);
        RectF bufferRect = new RectF(0, 0, previewSize.getHeight(), previewSize.getWidth());
        float centerX = viewRect.centerX();
        float centerY = viewRect.centerY();
        if (Surface.ROTATION_90 == rotation || Surface.ROTATION_270 == rotation) {
            bufferRect.offset(centerX - bufferRect.centerX(), centerY - bufferRect.centerY());
            matrix.setRectToRect(viewRect, bufferRect, Matrix.ScaleToFit.FILL);
            float scale = Math.max(
                    (float) viewHeight / previewSize.getHeight(),
                    (float) viewWidth / previewSize.getWidth());
            matrix.postScale(scale, scale, centerX, centerY);
            matrix.postRotate(90 * (rotation - 2), centerX, centerY);
        } else if (Surface.ROTATION_180 == rotation) {
            matrix.postRotate(180, centerX, centerY);
        }
        mTextureView.setTransform(matrix);
    }
    /**
     * surface ready的時候開啓Camera
     *
     * @param width  surface的寬
     * @param height surface的高
     */
    @SuppressLint("MissingPermission")
    private void openCamera(int width, int height) {
        CameraManager cameraManager = (CameraManager) mContext.getSystemService(Context.CAMERA_SERVICE);

        try {
            for (String cameraId : cameraManager.getCameraIdList()) {
                //描述相機設備的屬性類
                CameraCharacteristics characteristics = cameraManager.getCameraCharacteristics(cameraId);
                //獲取是前置還是後置攝像頭
                Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING);
                //使用後置攝像頭
                if (facing != null && facing == CameraCharacteristics.LENS_FACING_BACK) {
                    StreamConfigurationMap map = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);
                    if (map != null) {
                        //previewSize = CameraUtil.getOptimalSize(map.getOutputSizes(SurfaceTexture.class), width, height);
                        previewSize=new Size(mTextureView.getWidth(),mTextureView.getHeight());
                        mCameraId = cameraId;
                    }
                }
            }
            mImageReader = ImageReader.newInstance(previewSize.getWidth(), previewSize.getHeight(),
                    ImageFormat.JPEG, 2);
            mImageReader.setOnImageAvailableListener(mOnImageAvailableListener, mCameraHandler);
            cameraManager.openCamera(mCameraId, mStateCallback, mCameraHandler);
            configureTransform(previewSize.getWidth(),previewSize.getHeight());
        } catch (CameraAccessException r) {

        }
    }
    /**
     * 狀態回調
     */
    private CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {
        @Override
        public void onOpened(CameraDevice camera) {
            mCameraDevice = camera;
            SurfaceTexture surfaceTexture = mTextureView.getSurfaceTexture();
            surfaceTexture.setDefaultBufferSize(previewSize.getWidth(), previewSize.getHeight());
            Surface previewSurface = new Surface(surfaceTexture);
            try {
                mPreviewBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
                //如果需要多個surface可以add多個
                mPreviewBuilder.addTarget(previewSurface);
                mPreviewBuilder.addTarget(mImageReader.getSurface());
                //mPreviewBuilder.set(CaptureRequest.O, 270);
                mCameraDevice.createCaptureSession(Arrays.asList(previewSurface,mImageReader.getSurface()), mStateCallBack, mCameraHandler);
            } catch (CameraAccessException e) {
                e.printStackTrace();
            }
        }

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

        @Override
        public void onError(CameraDevice camera, int error) {
            camera.close();
        }
    };

    private CameraCaptureSession.StateCallback mStateCallBack = new CameraCaptureSession.StateCallback() {
        @Override
        public void onConfigured(CameraCaptureSession session) {
            CaptureRequest request = mPreviewBuilder.build();
            try {
                //獲取一個Image，one-shot
//                session.capture(request, null, mCameraHandler);
                //開啓獲取Image，repeat模式
                session.setRepeatingRequest(request, null, mCameraHandler);
            } catch (CameraAccessException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void onConfigureFailed(CameraCaptureSession session) {}
    };
    /**
     * 記得關掉Camera
     */
    public void closeCamera() {
        mCameraDevice.close();
    }
}

 

通過這個類可以把攝像頭預覽綁定到textureView上，然後的話。記得申請權限。我是 事先申請好了的。

使用的話應該看得懂吧 先 new，再init傳入textureView就好了。

然後旋轉的設置在configureTransform裏面。

關鍵語句

mPreviewBuilder.addTarget(previewSurface);
                mPreviewBuilder.addTarget(mImageReader.getSurface());
                //mPreviewBuilder.set(CaptureRequest.O, 270);
                mCameraDevice.createCaptureSession(Arrays.asList(previewSurface,mImageReader.getSurface()), mStateCallBack, mCameraHandler);

這裏要注意的是，加了兩種surface。下面也要相應地加入包含這兩種的list