Help surface view snap shot not working programmatically

[surface view]

i created surface view to rendering the h264 data as making video using RTSP without using default player for playing video .Now am programmatically takeup the snap shot for surface view that shows black screen for surface view content only, but shows root view content of surface view . But android default screen shot is fine .How to solve this problem on surface view ,please anyone provide solution.

example:
mFrameRenderingLayout.addView(mSurfaceView); // add the surface view to framelayout
View v1 =mSurfaceView.getRootView(); // represent rootview of surface view ie. mFrameRenderingLayout
v1.setDrawingCacheEnabled(true);
v1.buildDrawingCache();
(or)
mSurfaceView.setDrawingCacheEnabled(true);
mSurfaceView.buildDrawingCache();

File mFile;
BitMap mBitmapTemp;
String root = Environment.getExternalStorageDirectory() // Create path
.getAbsolutePath() + "/pictures";

Calendar newCalendar = Calendar.getInstance();
Date dt = newCalendar.getTime();
String tmp = mSDFFileformat.format(dt) + ".PNG"; // create file name
mFile = new File(root, tmp);
mBitmapTemp = Bitmap.createBitmap(v1
.getDrawingCache()); // get the drawing cache of surface view
v1.setDrawingCacheEnabled(false);
(or)
mBitmapTemp = Bitmap.createBitmap(v1
.getDrawingCache()); // get the drawing cache of surface view
mSurfaceView.setDrawingCacheEnabled(false);

FileOutputStream fos = null;
fos = new FileOutputStream(mFile);
if (fos != null) {
mBitmapTemp.compress(Bitmap.CompressFormat.PNG, 100,
fos); // compress the bitmap
fos.flush();
fos.close();


Finaly this code return black screen for surface view content only