hello, Ivano!

how can I help you today?

Hey Mark Good morning! Today....

would like to know about Retrofit2+RXJAVA is a small question, but on the book is not managed does it fine with you?

is about where to put the Subscriber to retrieve the object with the JSON reply

I eliminated onResponse

I cannot really help on RxJava questions

and does not work even if I put a Log is not retrieved

OK

I have played with it a bit, but nowhere near enough to be in position to help others

I am really focused on that at the moment

in 2017, I may be in better position to help

I understand is a huge topic with houndreads of operators, but I want to take advantage and specialize on that

OK I am going to study roboelectric/mockito/Junit session and will come back to you with some testing question that is also a topic that I want to master

um, OK

I may not be able to help there much either, as I stick mostly to instrumentation testing

in the meantime as architectural way to proceed

OK

I want to update my todolist application with a backend, i decided to use PHP... and...

I have some doubt regarding the architecture. basically it is not clear to me where I should update the app to maintain sync the content using sqlite internally and a content provider. where is best practice to put a POST request, and when a GET?

I highly doubt that there is a single "best practice" here

I have a fragment that update the db internally running queries to the content provider inside the fragment

basically I guess the steps should be.. 1) create a PHP service where to put an SQL DB. 2) update the DB on back end if user did not do in the past 3) add a POST <WHERE???> every time there is a modification in the DB 4) adding a GET everytime the app is opened instead to pass to the DB.

all of that, particularly steps 3 and 4, are very dependent upon how you want your app to work

I am afraid 3 could not work because user does not have connection to internet, so that cannot post, in this case what I should do? put in onStop cycle a request to the DB? and if still there is any internet connection?

"in this case what I should do?" -- keep track of what changes still need to be delivered, and arrange to do them sometime in the future (e.g., JobScheduler)

mmh

for example, perhaps you have a lastUpdated timestamp or something on relevant database rows

and you also track somewhere your last successful sync timestamp

then, at the next sync point, you need to deliver everything that is newer than the last successful sync timestamp

where "the next sync point" might be attempted in real time (if the user is actively in your app) or periodically (e.g., JobScheduler)

I start to shed some light

presumably, you plan on this same data being updated by the user by other means (e.g., Web app), otherwise there is no reason for the backend in the first place

in that case, you also have to push changes from the backend to the device

that could be GCM/FCM, MQTT, or just periodic polling

I see

with periodic polling as a fallback even if you optimize using some sort of push messaging solution (e.g., GCM/FCM, MQTT)

as those are not absolutely guaranteed to work

but, if instead, your backend is really just for a data backup, without live editing, then perhaps you do not update the backend live ever, settling for a nightly backup job

you gave me enough terms to run an extensive research: GCM, FCM, MQTT, sync timestamp, sync point. It was really hard for me to find some terms on my favorite search engine.

this is why I wrote that I highly doubt that there is a single "best practice"

of those, you will have the roughest time finding stuff on "sync timestamp" and "sync point"

those are fairly generic terms for which I expect there are many alternatives

GCM=Google Cloud Messaging, recently rebranded as FCM=Firebase Cloud Messaging

I forget exactly what MQTT stands for, but that's easily searchable

firebase sucks for my purposes

because I have complex queries

despite the branding, AFAIK, FCM is at best loosely coupled to the Firebase hosted database solution

and firebases offer only a limited way to query, because is a NOSQL technology

"Firebase" is becoming Google's overall brand for "hosted developer-focused services"

with the original Firebase database solution being just one of those

I see, google want to maintain this product because will become the google analytics of the apps

OK

I will try to look for tutorials PHP android

should be a good starting point I guess

I need to make things easy because I tend to make complex everything, and this is not good as my aim is to work in teams

have a nice day and see you soon!

and of course thanks

you are very welcome

that is a wrap for today's chat

the transcript will be uploaded to https://commonsware.com/office-hours/ shortly

the next chat is Saturday, 7:30pm US Eastern

have a pleasant day!