android,保存绘制的图片

Bitmap baseBitmap;
Canvas canvas;
Paint paint;
{
baseBitmap = Bitmap.createBitmap(320,360,Bitmap.Config.ARGB_8888);
canvas =new Canvas(baseBitmap);
canvas.drawColor(Color.WHITE);

paint = new Paint();
paint.setStrokeWidth(5);
paint.setColor(Color.GREEN);

//保存图片
File file = new File(Environment.getExternalStorageDirectory(),System.currentTimeMillis()+".jpg");
FileOutputStream stream =new FileOutputStream(file);
baseBitmap.compress(CompressFormat.JPEG, 100, stream);
stream.close();
Toast.makeText(this, "保存图片成功", 1).show();
//模拟一个消息，通知系统SD卡被重新挂载了
Intent intent = new Intent();
intent.setAction(Intent.ACTION_MEDIA_MOUNTED);
intent.setData(Uri.fromFile(Environment.getExternalStorageDirectory()));
sendBroadcast(intent);
}