打印手机摄像头的支持参数+将预览帧转换为位图
public class SecondActivity extends Activity implements SurfaceHolder.Callback,PreviewCallback{// 定义对象private SurfaceView mSurfaceview = null; // SurfaceView对象：(视图组件)视频显示private SurfaceHolder mSurfaceHolder = null; // SurfaceHolder对象：(抽象接口)SurfaceView支持类private Camera mCamera = null; // Camera对象，相机预览private String TAG = "SnapCamera";private boolean bIfPreview = false;private int mPreviewWidth;private int mPreviewHeight;Bitmap mBitmap = null;@Overrideprotected void onCreate(Bundle savedInstanceState){// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);setContentView(R.layout.activity_main);initSurfaceView();}// InitSurfaceViewprivate void initSurfaceView(){mSurfaceview = (SurfaceView) this.findViewById(R.id.CameraView);mSurfaceHolder = mSurfaceview.getHolder(); // 绑定SurfaceView，取得SurfaceHolder对象mSurfaceHolder.addCallback(SecondActivity.this); // SurfaceHolder加入回调接口// mSurfaceHolder.setFixedSize(176, 144); // 预览大小設置mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);// 设置显示器类型，setType必须设置}/* 【2】【相机预览】 */private void initCamera()// surfaceChanged中调用{Log.i(TAG, "going into initCamera");if (bIfPreview){mCamera.stopPreview();// stopCamera();}if (null != mCamera){try{/* Camera Service settings */Camera.Parameters parameters = mCamera.getParameters();// parameters.setFlashMode("off"); // 无闪光灯parameters.setPictureFormat(PixelFormat.JPEG); // Sets the image format for picture 设定相片格式为JPEG，默认为NV21parameters.setPreviewFormat(PixelFormat.YCbCr_420_SP); // Sets the image format for preview picture，默认为NV21/* * 【ImageFormat】JPEG/NV16(YCrCb format，used for * Video)/NV21(YCrCb format，used for Image)/RGB_565/YUY2/YU12 */// 【调试】获取camera支持的PictrueSize，看看能否设置List<Size> pictureSizes = mCamera.getParameters().getSupportedPictureSizes();List<Size> previewSizes = mCamera.getParameters().getSupportedPreviewSizes();List<Integer> previewFormats = mCamera.getParameters().getSupportedPreviewFormats();List<Integer> previewFrameRates = mCamera.getParameters().getSupportedPreviewFrameRates();Log.i(TAG + "initCamera", " support parameters is ");Size psize = null;for (int i = 0; i < pictureSizes.size(); i++){psize = pictureSizes.get(i);Log.i(TAG + "initCamera", "PictrueSize,width: "+ psize.width + " height:" + psize.height);}for (int i = 0; i < previewSizes.size(); i++){psize = previewSizes.get(i);Log.i(TAG + "initCamera", "PreviewSize,width: "+ psize.width + " height:" + psize.height);}Integer pf = null;for (int i = 0; i < previewFormats.size(); i++){pf = previewFormats.get(i);Log.i(TAG + "initCamera", "PreviewFormats:" + pf);}Iterator<Integer> it = previewFrameRates.iterator();while (it.hasNext()){Log.i(TAG + "initCamera", "PreviewFrameRates:" + it.next());}// 设置拍照和预览图片大小parameters.setPictureSize(640, 480); // 指定拍照图片的大小parameters.setPreviewSize(mPreviewWidth, mPreviewHeight); // 指定preview的大小// 这两个属性 如果这两个属性设置的和真实手机的不一样时，就会报错// 横竖屏镜头自动调整if (this.getResources().getConfiguration().orientation != Configuration.ORIENTATION_LANDSCAPE){parameters.set("orientation", "portrait"); //parameters.set("rotation", 90); // 镜头角度转90度（默认摄像头是横拍）mCamera.setDisplayOrientation(90); // 在2.2以上可以使用} else// 如果是横屏{parameters.set("orientation", "landscape"); //mCamera.setDisplayOrientation(0); // 在2.2以上可以使用}/* 视频流编码处理 */// 添加对视频流处理函数// 设定配置参数并开启预览mCamera.setParameters(parameters); // 将Camera.Parameters设定予CameramCamera.startPreview(); // 打开预览画面bIfPreview = true;// 【调试】设置后的图片大小和预览大小以及帧率Camera.Size csize = mCamera.getParameters().getPreviewSize();mPreviewHeight = csize.height;mPreviewWidth = csize.width;Log.i(TAG + "initCamera", "After setting, PreviewSize:width: "+ csize.width + " height: " + csize.height);csize = mCamera.getParameters().getPictureSize();Log.i(TAG + "initCamera", "After setting, PictrueSize:width: "+ csize.width + " height: " + csize.height);Log.i(TAG + "initCamera", "After setting, PreviewFormat is "+ mCamera.getParameters().getPreviewFormat());Log.i(TAG + "initCamera", "After setting, PreviewFrameRate is "+ mCamera.getParameters().getPreviewFrameRate());} catch (Exception e){e.printStackTrace();}}}/* 【SurfaceHolder.Callback 回调函数】 */public void surfaceCreated(SurfaceHolder holder)// SurfaceView启动时/初次实例化，预览界面被创建时，该方法被调用。{// TODO Auto-generated method stubmCamera = Camera.open();// 开启摄像头（2.3版本后支持多摄像头,需传入参数）try{Log.i(TAG, "SurfaceHolder.Callback：surface Created");mCamera.setPreviewDisplay(mSurfaceHolder);// set the surface to be// used for live previewmCamera.setPreviewCallback(SecondActivity.this);} catch (Exception ex){if (null != mCamera){mCamera.release();mCamera = null;}Log.i(TAG + "initCamera", ex.getMessage());}}public void surfaceChanged(SurfaceHolder holder, int format, int width,int height)// 当SurfaceView/预览界面的格式和大小发生改变时，该方法被调用{// TODO Auto-generated method stubLog.i(TAG, "SurfaceHolder.Callback: Surface Changed");mPreviewHeight = height;mPreviewWidth = width;initCamera();}public void surfaceDestroyed(SurfaceHolder holder)// SurfaceView销毁时，该方法被调用{// TODO Auto-generated method stubLog.i(TAG, "SurfaceHolder.Callback：Surface Destroyed");if (null != mCamera){mCamera.setPreviewCallback(null); // ！！这个必须在前，不然退出出错mCamera.stopPreview();bIfPreview = false;mCamera.release();mCamera = null;}}@Overridepublic void onPreviewFrame(byte[] data, Camera camera){// TODO Auto-generated method stubCamera.Parameters parameters = camera.getParameters();int format = parameters.getPreviewFormat();if (mBitmap != null){mBitmap.recycle();mBitmap = null;}// YUV formats require more conversionif (format == PixelFormat.YCbCr_420_SP|| format == PixelFormat.YCbCr_422_I){int w = 100/* parameters.getPreviewSize().width */;int h = 100/* parameters.getPreviewSize().height */;// Get the YuV image 由于此方法适用于android 2.2版本，所以此处不能用。// YuvImage yuv_image = new YuvImage(data, format, w, h, null);// // Convert YuV to Jpeg// Rect rect = new Rect(0, 0, w, h);// ByteArrayOutputStream output_stream = new// ByteArrayOutputStream();// yuv_image.compressToJpeg(rect, 100, output_stream);// // Convert from Jpeg to Bitmap// bitmap2 = BitmapFactory.decodeByteArray(output_stream// .toByteArray(), 0, output_stream.size());int[] i = new int[data.length];decodeYUV420SP(i, data, w, h);mBitmap = Bitmap.createBitmap(i, w, h, Bitmap.Config.RGB_565);// mBitmap = renderCroppedGreyscaleBitmap(data, w, h);// Log.e(TAG, "Image format is YUV:" + format);}// Jpeg and RGB565 are supported by BitmapFactory.decodeByteArrayelse if (format == PixelFormat.JPEG || format == PixelFormat.RGB_565){// Log.e(TAG, "Image format is JPEG/RGB:" + format);mBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);}}private void decodeYUV420SP(int[] rgb, byte[] yuv420sp, int width,int height){// TODO Auto-generated method stubfinal int frameSize = width * height;for (int j = 0, yp = 0; j < height; j++){int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;for (int i = 0; i < width; i++, yp++){int y = (0xff & ((int) yuv420sp[yp])) - 16;if (y < 0)y = 0;if ((i & 1) == 0){v = (0xff & yuv420sp[uvp++]) - 128;u = (0xff & yuv420sp[uvp++]) - 128;}int y1192 = 1192 * y;int r = (y1192 + 1634 * v);int g = (y1192 - 833 * v - 400 * u);int b = (y1192 + 2066 * u);if (r < 0)r = 0;else if (r > 262143)r = 262143;if (g < 0)g = 0;else if (g > 262143)g = 262143;if (b < 0)b = 0;else if (b > 262143)b = 262143;rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000)| ((g >> 2) & 0xff00) | ((b >> 10) & 0xff);}}}}在给定最大范围的条件下获取最佳预览的方法：
private void getBestPreviewSize(Camera camera, Parameters parameters, SurfaceView cameraView){int bestWidth=0;int bestHeight=0;List<Size> previewSizes=parameters.getSupportedPreviewSizes();if(previewSizes.size()>1){Iterator<Size> cei=previewSizes.iterator();while(cei.hasNext()){Size aSize=cei.next();Log.v("snap shot","Checking "+aSize.width+"*"+aSize.height);if(aSize.width>bestWidth && aSize.width<=LARGETST_WIDTH && aSize.height >bestHeight&& aSize.height<=LARGETST_HEIGHT){bestWidth=aSize.width;bestHeight=aSize.height;}}if(bestHeight!=0 && bestWidth!=0){Log.v("snap shot","Using "+bestWidth+"*"+ bestHeight);parameters.setPreviewSize(bestWidth,bestHeight);cameraView.setLayoutParams(new LinearLayout.LayoutParams(bestWidth,bestHeight));}}camera.setParameters(parameters);}
