A/B Test Like a Pro #5: How I Added Remote Config to my iOS App Video Lecture | Introduction A/B Testing: From Experiment to Result - Software Testing

hey there app developers so this episode
of a be test like a pro is completely
optional I know I've been showing you
this sample app that makes use of remote
config and some of you wanted me to go
into more of the details around how I
got this working and so while I don't
really want to derail this series with
kind of detailed explanations of how to
implement remote config because you know
we've already got like Docs and blog
posts and videos all about that I
thought for those of you who are curious
about how I got remote config working in
my app I'd walk you through the code so
ready let's start now I do want to
preface this by saying this is one way
you can get your app up and running with
remote config it's not the only way and
it's not necessarily the best way so if
you think you've got a better system set
up within your app keep using it and you
know maybe tell me about it in the
comments below alright let's take a look
at my code so let's start off by taking
a look at my RC values object which is
what I use for accessing all of my
remote config the implementation details
now it's a singleton because I'm is
guilty is overusing Singleton's as the
next engineer but it does make life
awfully easy for me so the first thing I
want to point out is that I'm storing
all of my remote config keys here as a
swift enum with the backing type as a
string now this is nice in that if I ask
for the raw value of an enum it will be
a string that's equal to this value here
unless I specify otherwise so the raw
value of slogan text is actually a
string called slogan txt and it turns
out that if I do need to override one of
these like maybe because the Android
team already shipped their version of
the app and they're using a different
term I can do that easily like this so
when my singleton object is first
initialized which as you can see I am
doing here in my app delegate I do two
things first I specify default values
and then I fetch new values from the
cloud so first let's take a look at how
I'm specifying my defaults the two
things I want to point out here are that
I'm grabbing the raw value from my enum
as the key which as you recall is a
string that usually has the same name as
the enum itself and then here you can
see that I'm using my NS localized
string to set my default values for my
strings so that
run-time I can make sure my default
values are still appropriately localized
even though I'm going through remote
config now fetching values from the
cloud should look pretty familiar I'm
making a call and then calling activate
fetched here in the completion handler
although this bit here might be new
notice that I'm setting fetch complete
to true and calling my loading done call
back if it exists and that's because I'm
using a loading screen now if you
haven't watched our video called remote
configured in strategies I do recommend
taking a look at it I go over three
different strategies for how to load and
apply remote config file use and one
solution I recommend is creating a
loading screen that you can put up while
you're waiting for your remote
configures to finish loading and that's
what I'm doing here so over here in my
waiting screen view controller I'm
basically setting our loading done call
back to this ready to go method that
segues to the next view controller I'm
also calling it right away if fetch
complete is true just on the off-chance
that remote configs somehow completed
its fetched before this view was loaded
I don't know if that's possible but you
know better safe than sorry
and so you'll notice this is why even if
I get an error fetching a wrote config I
don't want to completely bail out early
from this function I still want to set
fetch complete is true and call my
loading done callback so that if I'm
offline or my app is throttled or
something I'm not stuck forever on the
loading screen now once we get into my
main view controller you can see I have
this method apply config values where
I'm setting a bunch of values for my app
from what's in remote config and this is
because I need to set all this stuff
through code and I can't necessarily
rely on what I've set in the storyboard
now you can see that instead of
accessing the remote config service
directly I'm making calls like this
config dot string for key method let's
take a closer look at some of these
methods I think most of them are pretty
straightforward what I'm doing here is
simply taking my values from wrote
config and calling bool value string
value number value whatever on them if I
do end up with a nil value I provide a
simple default that way I don't have to
deal with these things as optionals in
the rest of my code you'll notice that
color for key returns a UI color based
on the string value that I retrieved
from remote config now this is not
currently a native UI color method
I'm using the uicolor hex Swift library
which adds it on to the UI color class
as an extension now the one place I am
getting a little tricky is here in the
populate image view for key method
basically I want to find an easy way to
change images through remote config and
I decide to do that through a JSON
object or I guess more accurately a
string that looks like a JSON object
something like this now the source here
is either local or remote if it's local
there will be a name field that's the
name of the local file to use and if
it's remote there will be a URL field
for the images URL that I want to load
and so in my code the first thing you
can see I'm doing is loading up a
default image just in case like my JSON
is broken or something next I try to
grab my string from remote config and
parse it as a JSON object I then look to
see if the source value is equal to the
string remote if it is then I look for a
URL and try and load that into my image
now if that fails for any reason or I
forget to include a URL parameter I can
go back to using my default image
otherwise I try to grab the value of the
name field for my JSON and then I'll
simply load the image locally based on
that name note that I'm using both the
swiftie JSON library to parse my JSON
and the SD web image library to take
care of all the hay load this image from
the web work for me one note about the
swiftie json library is that it doesn't
really rely on optionals
so if my JSON is broken or it doesn't
include a source value it will give me
an empty string instead of nil and
that's why you don't see me doing a
whole bunch of guard let's in most of my
JSON interpreting code here if my JSON
doesn't have a field called source this
local or remote value will just be an
empty string as for this default image
one option could be to just simply hard
code this to some placeholder UI image
but what I decided to do instead is take
a look at what I specified within my
remote config defaults which you know
makes sense right that seems like a
pretty reasonable backup image to use if
my remote config file use incorrect and
so that's what I'm doing here i'm
calling this default value for key
method to ask remote config for the
default value instead of what's been
loaded from the cloud note that by the
time you see this video you might not
need to make this call with the
namespace argument
but I had to then basically all I'm
gonna do here is grab the contents of my
Jason's name field and try to get a
local UI image from that value now I am
making two assumptions here one is that
I will have a valid JSON object
representing images for my default
options in remote config and two is that
they'll all be local but at least for my
app I think those are both safe
assumptions to make and in fact that's
why I'm throwing an assertion error here
because I do want to make sure I have
good default options to fall back on and
I want to catch that in development but
of course feel free to change this logic
if it's not appropriate for your app and
then well that's basically it I grabbed
these values from my RC value singleton
as I need them using these methods that
either return non optional values of the
right type or this populate image view
method that loads the appropriate image
right into the correct view I use the
same approach when animating my views
and just as a fun side note here I'm
animating my slide in panel by changing
the constraint constant here which is a
neat way of being able to animate my
views while still using constraints
within my app this really has nothing to
do with remote config I just thought it
was kind of cool and there you go
so that's the app I have set up in iOS
if you do want any more information
about any of this stuff head on over to
the remote config section of our
documentation and be sure to check out
the samples and all the guides and all
the videos we got waiting for you there
and yes we even have stuff there for you
Android folks so in meantime if you
enjoyed this video please feel free to
subscribe to the firebase YouTube
channel and I will see you soon on
another exciting episode of a be test
like a pro thanks for watching