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;
@Override
protected void onCreate(Bundle savedInstanceState)
{
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initSurfaceView();
}
// InitSurfaceView
private 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NV21
parameters.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Camera
mCamera.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 stub
mCamera = 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 preview
mCamera.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 stub
Log.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 stub
Log.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;
}
}
@Override
public void onPreviewFrame(byte[] data, Camera camera)
{
// TODO Auto-generated method stub
Camera.Parameters parameters = camera.getParameters();
int format = parameters.getPreviewFormat();
if (mBitmap != null)
{
mBitmap.recycle();
mBitmap = null;
}
// YUV formats require more conversion
if (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.decodeByteArray
else 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 stub
final 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);
}
