Posting image from android app to facebook

i really need help, i'm developing android app where there is a part i can post image and videos to Facebook , my Facebook APP have the basic permissions (public_profile,email,user_friends) but before posting i'm requesting from publish_actions permission using this method :

public void requestPermissions() {
    Session s = Session.getActiveSession();

    if (s != null)
    {
        Session.NewPermissionsRequest newPermissionsRequest = new Session.NewPermissionsRequest(
                this, PERMISSIONS);
        s.requestNewPublishPermissions(newPermissionsRequest);
    }


}

but it never show dialog for confirming this permission and hence the posting image is not working , here is my method:

// share on facebook
    public synchronized void postImage(String imagePath) {

            // change the image
            //Bitmap img = BitmapFactory.decodeFile(recievedImageURI);
        if(checkPermissions())
        {
            Bitmap image=BitmapFactory.decodeFile(imagePath);
            Request uploadRequest = Request.newUploadPhotoRequest(
                    Session.getActiveSession(),image, new Request.Callback() {
                        @Override
                        public void onCompleted(Response response) {
//                          Toast.makeText(getApplicationContext(),
//                                  "Photo uploaded successfully",
//                                  Toast.LENGTH_LONG).show();
                            //showDailog2("Photo uploaded successfully");
                            Intent gotoShare=new Intent(getApplicationContext(), FlickerActivity.class);
                            startActivity(gotoShare);


                        }
                    });
            uploadRequest.executeAsync();
            FlickerActivity.uploadNext();

        }
        else
        {
            requestPermissions();
        }


    }