Getting the path to upload Image from Android to Server

I'm working on code to allow user to choose image from gallery and upload it to server using Base64. every thing work fine until I test the code on API > 19 and getting an error. I appreciate your help so much.

Here is my code:

    // Upload Image :)

    camera.setOnClickListener(new OnClickListener () {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
               Intent intent = new Intent();
                intent.setType("image/*");
                intent.setAction(Intent.ACTION_GET_CONTENT);
                startActivityForResult(Intent.createChooser(intent, "Complete action using"), 1);   
        }});


    btn_send_experience.setOnClickListener(new OnClickListener () {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            new AddExperience().execute();
        }});


} // End Of On Create

  @Override
  public void onActivityResult(int requestCode, int resultCode, Intent data) {

      if (requestCode == 1 && resultCode == RESULT_OK) {
             //Bitmap photo = (Bitmap) data.getData().getPath(); 

             Uri selectedImageUri = data.getData();
             imagepath = getPath(selectedImageUri);
             Bitmap image =BitmapFactory.decodeFile(imagepath);
             imageView_pic.setImageBitmap(image);
             imageData = encodeTobase64(image);
             Toast.makeText(Share_event_experience.this, imagepath, Toast.LENGTH_LONG).show();
      }
     }


  public static String encodeTobase64(Bitmap image) {
        System.gc();

        if (image == null) return null;

        Bitmap immagex = image;
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        immagex.compress(Bitmap.CompressFormat.JPEG, 100, baos);

        byte[] b = baos.toByteArray();

        String imageEncoded = Base64.encodeToString(b, Base64.DEFAULT); // min minSdkVersion 8

        return imageEncoded;
    }


     public String getPath(Uri uri) {
              String[] projection = { MediaStore.Images.Media.DATA };
              Cursor cursor = managedQuery(uri, projection, null, null, null);
              int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
              cursor.moveToFirst();
              return cursor.getString(column_index);
          }

Then I send the value "imageData" using ASyncTask to php file.

The error I get when I try On API > 19:

04-15 10:16:07.497: E/BitmapFactory(1357): Unable to decode stream: java.lang.NullPointerException