android 实现录像时拍照

实现思路：点击拍照按钮后，获取摄像头的一帧数据，转换成jpg格式，保存到文件中。
Activity 继承Camera.PreviewCallback
重写public void onPreviewFrame(byte[] data, Camera camera)；
首先创建MediaRecorder，Camera实例

创建camera

if (mCamera == null) {
            mCamera = Camera.open();
        }
        mCamera.setPreviewDisplay(holder);
        mCamera.startPreview();
        mCamera.setPreviewCallback(this);

`
创建MediaRecorder：

if (mediaRecorder == null) {
            mediaRecorder = new MediaRecorder();
        }

设置mediaRecorder属性

mediaRecorder.reset();
        ***mediaRecorder.setCamera(mCamera);***
        setVideoOrientation();
        mediaRecorder.setVideoSource(MediaRecorder.VideoSource.CAMERA); //从照相机采集视频
        mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
        mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
        mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
        mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
        mediaRecorder.setVideoSize(size.width, size.height);//设置分辨率
        mediaRecorder.setVideoFrameRate(10);
        mediaRecorder.setVideoEncodingBitRate(3 * 1024 * 1024);
        setVideoMaxDuration();
        File videoFile = new File(Tools.getPath(), fileName + ".3gp"); //保存路径及名称
        mediaRecorder.setOutputFile(videoFile.getAbsolutePath());
        try {
            mediaRecorder.prepare();//预期准备
            mediaRecorder.start();//开始刻录
        } catch (Exception e) {
            e.printStackTrace();
        }
        mHandler.sendEmptyMessageDelayed(MSG_START_RECORDER, 3000);//延时设置previewCallBack，防止回调消失。

在 onPreviewFrame(byte[] data, Camera camera)中获取一帧数据然后转换成jpg图片
数据处理放在线程中。isTakePic为拍照的标志位，当点击拍照按钮是置为true，开始从预览图像中获取一帧数据

public void onPreviewFrame(byte[] data, Camera camera) {
        // At preview mode, the frame data will push to here.
        FrameLaneData = data;//.clone();
        FrameCarData = data;//.clone();
        if (isTakePic) {
            isTakePic = false;
            shutterCallback.onShutter();
            previewSize = mCamera.getParameters().getPreviewSize();
            new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        yunImage = new YuvImage(FrameLaneData, ImageFormat.NV21, previewSize.width, previewSize.height, null);
                        if (yunImage != null) {
                            ByteArrayOutputStream strem = new ByteArrayOutputStream();
                            yunImage.compressToJpeg(new Rect(0, 0, previewSize.width, previewSize.height), 80, strem);
                            Bitmap bitmap = BitmapFactory.decodeByteArray(strem.toByteArray(), 0, strem.size());
                            SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd_HHmmss");
                            String fileName = format.format(new Date());
                            File file = new File(Tools.getPath() + fileName + ".jpg");
                            BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
                            bitmap.compress(Bitmap.CompressFormat.JPEG, 80, bos);//将图片压缩到流中
                            bos.flush();//输出
                            bos.close();//关闭
                            strem.close();
                            bitmap.recycle();
                            mHandler.sendEmptyMessage(MSG_TAKE_PICTURE);
                        }
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }).start();
        }
        }

在开启录像之后可能会不执行回调方法，解决办法：在开启录像3s后再次设置回调，见代码注释。