全网最简单实用Android平板USB摄像头开发，同时预览多个摄像头，双目摄像头，同时打开手机前后摄像头（红外摄像头、人脸识别、活体检测、Android Camer

老规矩， 先视频

8月20日

背景：多摄像头有很多实现方案，手机上能实现跑通，但是Android平板USB的找了好久才实现，需要低版本API，

废话不多说  直接代码：

工具类

import android.graphics.SurfaceTexture;
import android.hardware.Camera;
import android.view.TextureView;

import java.io.IOException;
import java.util.List;

public class PreviewCamera {

    private Camera mCamera;
    private boolean mirror = false; // 镜像（左右翻转）
    private int rotate = -1; // 旋转（相机传感器方向相对于设备自然方向的角度）
    private int zoom = -1; // 焦距（有些摄像头可能不支持）

    public void setMirror(boolean mirror) {
        this.mirror = mirror;
    }

    public void setRotate(int rotate) {
        this.rotate = rotate;
    }

    public void setZoom(int zoom) {
        this.zoom = zoom;
    }

    public void startCamera(TextureView textureView, int cameraIndex, int width, int height, ICallback callback) {
        stopCamera();
        try {
            mCamera = Camera.open(cameraIndex);
            checkPreviewSize(width, height);
            // 设置参数（尺寸、对焦、焦距、旋转）
            Camera.Parameters params = mCamera.getParameters();
            //List list = params.getSupportedPreviewFormats();
            params.setPreviewSize(width, height);
            List focusModes = params.getSupportedFocusModes();
            if (focusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)) {
                params.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
            }
            if (this.zoom >= 0 && params.isZoomSupported() && this.zoom <= params.getMaxZoom()) {
                params.setZoom(this.zoom);
                mCamera.setParameters(params);
            }
            mCamera.setParameters(params);
            if (this.rotate >= 0) {
                mCamera.setDisplayOrientation(this.rotate);
            }
            // 预览初始化（左右翻转）
            initPreview(textureView);
            if (this.mirror) {
                textureView.setRotationY(180);
            }
            // 回调
            mCamera.setPreviewCallback(new Camera.PreviewCallback() {
                @Override
                public void onPreviewFrame(byte[] data, Camera camera) {
                    if (callback != null) {
                        callback.onData(data, camera);
                    }
                }
            });
            if (callback != null) {
                callback.onSucc(mCamera);
            }
        } catch (Exception e) {
            e.printStackTrace();
            if (callback != null) {
                callback.onError(e);
            }
        }
    }

    public void stopCamera() {
        try {
            mCamera.setPreviewCallback(null);
            mCamera.stopPreview();
            mCamera.release();
            mCamera = null;
        } catch (Exception e) {
        }
    }

    private void checkPreviewSize(int width, int height) throws Exception {
        boolean sizeOk = false;
        List sizeList = mCamera.getParameters().getSupportedPreviewSizes();
        for (Camera.Size size : sizeList) {
            if (size.width == width && size.height == height) {
                sizeOk = true;
            }
        }
        if (!sizeOk) {
            throw new Exception(String.format("不支持该预览尺寸: [%d,%d]", width, height));
        }
    }

    public Camera getCamera(){
        return this.mCamera;
    }

    private TextureView initPreview(TextureView textureView) {
        textureView.setSurfaceTextureListener(new TextureView.SurfaceTextureListener() {
            @Override
            public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int i, int i1) {
                try {
                    if (mCamera != null) {
                        mCamera.setPreviewTexture(surfaceTexture);
                        mCamera.startPreview();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

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

            }

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

            @Override
            public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {

            }
        });
        return textureView;
    }

    public interface ICallback {
        void onSucc(Camera camera);

        void onData(byte[] data, Camera camera);

        void onError(Exception e);
    }
}

调用预览：

 private void start() {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.CAMERA) == PackageManager.PERMISSION_DENIED) {
            requestPermissions(new String[]{Manifest.permission.CAMERA}, PERMISSION_CAMERA_REQUEST_CODE);
        }

        // 设置镜像（左右翻转）
        previewCamera1.setMirror(false);
        // 设置旋转角度
        //previewCamera1.setRotate(90);

        // 设置焦距
        //previewCamera1.setZoom(50);

        previewCamera1.startCamera(binding.textureView1, CAMERA_ID_1, CAMERA_WIDTH, CAMERA_HEIGHT, null);
        if (numberOfCameras == 2) {
            previewCamera2.setMirror(false);
            // 设置旋转角度
            //previewCamera2.setRotate(90);

            // 设置焦距
            //previewCamera2.setZoom(50);
            previewCamera2.startCamera(binding.textureView2, CAMERA_ID_2, CAMERA_WIDTH, CAMERA_HEIGHT, null);
        }

    }

    private void stop() {
        previewCamera1.stopCamera();
        if (numberOfCameras == 2) {
            previewCamera2.stopCamera();
        }
    }

拍照：

 @IOThread
    private void takePhoto() {
        Camera camera1 = previewCamera1.getCamera();

        camera1.takePicture(null, null, new Camera.PictureCallback() {
            @Override
            public void onPictureTaken(byte[] bytes, Camera camera) {
                camera.startPreview();
//                Log.e("bytes", "bytes: " + bytes.length);
                byte[] uploadBytes = compressByQuality(bytes, 512);
//                Log.e("uploadBytes", "uploadBytes: " + uploadBytes.length);
                uploadFile(uploadBytes,CAMERA_ID_1);
            }
        });

        if(numberOfCameras == 2){
            Camera camera2 = previewCamera2.getCamera();
            camera2.takePicture(null, null, new Camera.PictureCallback() {
                @Override
                public void onPictureTaken(byte[] bytes, Camera camera) {
                    camera.startPreview();
//                    Log.e("bytes", "bytes1: " + bytes.length);
                    byte[] uploadBytes = compressByQuality(bytes, 512);
//                    Log.e("uploadBytes", "uploadBytes1: " + uploadBytes.length);
                    uploadFile(uploadBytes,CAMERA_ID_2);
                }
            });
        }


//        binding.cameraView1.captureImage();
//        binding.cameraView2.captureImage();
    }

上面是做了摄像头有一个和两个的兼容

参考：http://t.csdnimg.cn/zL80I