ShareImageToFacebook.kt

// import facebook sdk
// import facebook sharing sdk

private fun onShareFacebook(bitmap: Bitmap) {
  
  val photoToShare = SharePhoto.Builder().setBitmap(bitmap).build()
  
  val contentToShare = SharePhotoContent.Builder().addPhoto(photoToShare)
            .setShareHashtag(ShareHashtag.Builder().setHashtag("#MarcosDavalos").build())
            .build()
  val shareDialog = ShareDialog(this)
  
  if(ShareDialog.canShow(SharePhotoContent::class.java)){
    shareDialog.show(contentToShare)
  }else{
    Log.e(TAG, "dialog can't show") 
  }
}