Android 拍照

左手的ㄟ右手 2022-05-18 05:43 243阅读 0赞

1.implements SurfaceHolder.Callback

可缓存线程池，如果线程池长度超过处理需要，可灵活回收空闲线程，若无可回收，则新建线程

ExecutorService executorService = Executors.newCachedThreadPool(); public void initView() \{

mSurfaceView = findViewById(R.id.surface);

//SurfaceHolder.Callback()用于监听surface的生命周期

mSurfaceHolder.addCallback(this);  
mSurfaceHolder = mSurfaceView.getHolder();

@Override
    protected void onStart() {
        super.onStart();
        if (this.checkCameraHardware(this) && (mCamera == null)) {
            try {
                setCameraFace();
            } catch (Exception e) {
                e.printStackTrace();
            }
            Log.d("onStart", "onStart");
        }
    }

// 设置摄像头方向
    public void setCameraFace() {
        int cameraCount = 0;
        Camera.CameraInfo cameraInfo = new Camera.CameraInfo();
        cameraCount = Camera.getNumberOfCameras();// 得到摄像头的个数
        for (int i = 0; i < cameraCount; i++) {
            Camera.getCameraInfo(i, cameraInfo);// 得到每一个摄像头的信息
            // 现在是后置，变更为前置
            if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
                /*
     * 记得释放camera，方便其他应用调用
     */
                releaseCamera();
                // 打开当前选中的摄像头
                mCamera = Camera.open(i);
                if (mCamera != null) {
                    Camera.Parameters params = mCamera.getParameters();
                    params.setPictureFormat(ImageFormat.JPEG);
                    params.setPreviewSize(800, 400);
                    // 自动对焦
                    //  params.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
                    params.setJpegQuality(40);
                    //  params.setPictureSize(300,300);
                    mCamera.setParameters(params);
                }
            }
        }
    }

/**
     * 释放mCamera
     */
    private void releaseCamera() {
        if (mCamera != null) {
            mCamera.setPreviewCallback(null);
            mCamera.stopPreview();// 停掉原来摄像头的预览
            mCamera.release();
            mCamera = null;
        }
    }

/**
     * Check if this device has a camera
     */
    private boolean checkCameraHardware(Context context) {
        if (context.getPackageManager().hasSystemFeature(
                PackageManager.FEATURE_CAMERA)) {
            // this device has a camera
            return true;
        } else {
            // no camera on this device
            return false;
        }
    }

/**
     * 设置camera显示取景画面,并预览
     *
     * @param camera
     */
    private void setStartPreview(Camera camera, SurfaceHolder holder) {
      /*  Log.d("onStart", "setStartPreview");
        try {
            if (camera != null) {
                camera.stopPreview();
                camera.setPreviewDisplay(holder);
                camera.startPreview();
                }
        } catch (Exception e) {
            e.printStackTrace();
        }*/
        try {
              setCameraFace();
             
            //预览拍照
            mCamera.setPreviewDisplay(holder);
            camera.startPreview();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

@Override
    public void surfaceCreated(SurfaceHolder surfaceHolder) {
        Log.d("onStart", "surfaceCreated");
        setStartPreview(mCamera, surfaceHolder);
        //  mHandler.postDelayed(runnbale,10000);
    
    
    }
    
    @Override
    public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i1, int i2) {
        Log.d("onStart", "surfaceChanged");
        if (mSurfaceHolder.getSurface() == null) {
            return;
        }
    
        // stop preview before making changes
        try {
            mCamera.stopPreview();
        } catch (Exception e) {
            // ignore: tried to stop a non-existent preview
        }
        setStartPreview(mCamera, surfaceHolder);
    
    }

@Override
    public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
        // 当surfaceview关闭时，关闭预览并释放资源
        releaseCamera();
        mSurfaceHolder = null;
        mSurfaceView = null;
    }

void takephoto(final String cardNumber) {
        mCamera.takePicture(null, null, new Camera.PictureCallback() {
    
            @Override
            public void onPictureTaken(final byte[] bytes, Camera camera) {
               
                executorService.execute(new Runnable() {
                    @Override
                    public void run() {
                        setStartPreview(mCamera, mSurfaceHolder);
                       //设置线程为前端进程
                        android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_FOREGROUND);
                        Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
                        String imgName = "";
                        FileOutputStream fos = null;
                        try {
                            try {
                         //将照片保存到本地
                                fos = new FileOutputStream("/sdcard/DCIM/" + (imgName = "a"+"_"+cardNumber+"_"+                System.currentTimeMillis()) + ".jpg");                       
                            } catch (Exception e) {
    
                            } finally {
                                fos.flush();
                                fos.close();
                            }
                  
                          
                });
            }
    
        });
    }

如果`mCamera.takePicture(null, null, new Camera.PictureCallback() {}方法没有回调`

可能的原因是：没有预览拍照   mCamera.setPreviewDisplay(holder); mCamera.startPreview();