Get uri from camera intent in android

on click

 takePic.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View arg0) {
                Intent m_intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                imageUri = getImageUri();
                m_intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
                startActivityForResult(m_intent, REQUEST_IMAGE_CAPTURE);
            }
        });

On Result:

 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == REQUEST_IMAGE_CAPTURE
                    && resultCode == RESULT_OK) {   

                Log.d("test1",""+imageUri);
                Intent shareIntent = new Intent(this, SharePicForm.class);
                shareIntent.putExtra("photo",""+imageUri);
                startActivity(shareIntent);
            }

        }

getImageUri()

private Uri getImageUri(){
        Uri m_imgUri = null;
        File m_file;
        try {
            SimpleDateFormat m_sdf = new SimpleDateFormat("yyyyMMdd_HHmmss");
            m_curentDateandTime = m_sdf.format(new Date());
            m_imagePath = Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + m_curentDateandTime + ".jpg";
            m_file = new File(m_imagePath);
            m_imgUri = Uri.fromFile(m_file);
        } catch (Exception p_e) {
        }
        return m_imgUri;
    }

What I would like to achieve is very simple, call camera intent and get the uri of the result photo. But it seems there is an inconsistent of different device and on my device it isn't work at all. I tried to store the path on a public variable but when I retrieve it , it is null, is there formal and standard way to implement it and should be work on all device? Also, are there any way for not provide the custom path but get the default uri path from the camera intent ?

Thanks for helping