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what is progard progard is a open source tool
that we can use to shrink optimize off firstate
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our Java bite code it shrinks APK size by removing
the unused code and off forticate the remaining
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code to prevent from reverse engineering So Pro
card first detect all of your unused code from
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your APK and it will simply remove that code by
doing this thing it will automatically decrease
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your APK size and once your APK size decreased
automatically performance- wise it will behave
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better so let's understand understand this thing
with a very simple scenario suppose you are using
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one Library into your project that contain 10
different feature but you are interested only
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one feature now what will happen with the nine
different features that your library contains
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well if you are not using progard and generating
your APK this nine feature is included into your
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APK and ultimately it will increase your APK size
now what will happen if you are using progard on
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that case it will simply eliminate those 9 feature
from your APK by doing this automatically your APK
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size will be decreased and performance- wise it
will behave better than the previous APK so this
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is the use case of progard next it enhances
your security so automatically it will off
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forticate all of your class name function name
attributes name into uh some zis so that no one
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can access or try to understand your code very
easily if your source code contain one function
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naming get images now after autic this get images
function name will be converted into uh let's say
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ABC even though you have written your own code
base but after offes station you are not able to
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understand so this is very important thing because
if somehow someone access your code Bas is still
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they have to decode all of the offes station
to get the original code so this is the benefit
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of using progard so always use progard in your
project so let's see how we can use progard in
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our Android project but before that in Android we
are using R8 now R8 is a better version of progard
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performance- wise it will behave better than
progard and also it will reduce the build time
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so let's see how we can enable it in our project
and see how officiation looks like so for that
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you will need a project so simply create a new
project for yourself I have created that project
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for myself now it's time to begin with it so here
just change your mode from Android to project open
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up your build. gill. kts of module app level in
your Android closer we have build type and in
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this build type we have release so mostly we'll
use progard in our release build because release
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build is open source and everyone can download it
and see it very easily so that's why Always apply
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progard in your release version cool so here you
can see is Minify enabled is Minify enabled is
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the key that is used to determine whether PR guard
is enable in your project or not so initially it
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is false so I'm going to use True by using true
automatically it will enable progard for us next
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we have here progard files now this is the
file that contains set of rules for optimiz
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optimization this is mostly used to optimize
Android applications so all of the rules the
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logic how ofation will be happen under the hood
is written over here next we have progard rules.
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proo this is the file and in this file we'll write
something something something in this video just
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wait for it all right so in our build gal kts I'm
enabling my PR guard and this thing is actually
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used to handle the progard things next we have
here is shrink resources so once you enable this
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Minify enable to true it will enable the prart for
your sour code that is present in your Java folder
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over here if you want to shrink your resources to
that present in this uh directory on that case you
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can use is string resources true now what it will
do uh let's say in our values string.xml I have
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one more string uh naming something something
something and its value is something something
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something but I'm not using it so if you are using
is shrink resources true it will automatically
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remove this thing after the offest station so
this is a use case of is shrink resources all
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right so now it's time to play with progard so
for that first I'm going to create a package
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and the package name is fake and in this fake
I'm going to create a class to be more specific
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it's a data class that contain name as a member
variable let's use this thing in our main activity
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import it name is my name which is himansu in
place of Android I'm using my fake name okay
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sync your project so that it will enable Pro card
okay so if you want to see the off station for
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that change the build variant from debug which is
default one to release and sync your project after
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that go on the top in the build we have here clean
project so simply clean your project and rebuil it
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because we have been enabled is bifi enabled true
aing resources true it will take little more time
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to perform all of those operations okay so here
we have a build folder open up this build folder
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in the outputs we have mapping that contains a
file naming mapping. txt this is the file that
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is used to map your class T to offest deated
name so here you can see this is our fake data
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class now it will be renamed into no o. a so in
the real codebase after aestic you are not able
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to understand what is the meaning of this so this
is how you can perform aestic okay so let's see
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how we can prevent this fake from offes station
sometimes you have to prevent a few classes from
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offest station so let's see how we can do it so
for that go to your fake data class and on the
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top you can use annotation keep now again clean
your project and rebuild it okay open up your
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build outputs mapping mapping. txt and search for
fake do KT and this time you can see this is our
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actual data class name and this time it won't
off forticate it because uh we are preventing
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this thing by using this keep annotation so by
using this keep annotation you can prevent it
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remove this keep annotation uh let's do the
same thing with our PR guard. profile which
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present over here so let's say I want to
prevent the class fake from off station
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so for that you can use D keep class and
mention the class name which is fake okay
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again just clean your project and rebuild it
go to the top look out for the build output
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mapping mapping. txt just search for fake do
KT here you can see it is not offes deticated
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cool now let's do one more thing so I'm going
to create an interface in a package and the
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package name is inter uh we have a interface
and the interface name is fake interface that
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contain one function in it get custom message
return type of this function is string now we
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have two different classes that actually
implemented this interface so for that I'm
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going to create a package which is IML we have
here our first IML class which implements fake
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interface similarly we have
one more class naming second
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IML it uses fake interface and provide its
implementation uh return uh we have here
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second IM cool so now it's time to use it go to
your main activity and on the top I'm going to
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create a private while first IM with the help
of first IM next we have private while second
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IM and create an object of second IML it's time
to use it so here I'm using plus function first
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implementation. get custom message again I'm
using plus function this time I'm using second
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implementation. get custom message all right
so just clean the project and rebuild it open
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up the build folder outputs mapping mapping. txt
uh let's search for our first Im so see first IM
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will become W and our second IM will become X cool
so if you check all the other things regarding the
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first implementation yeah so first implementation
will become W now I want to prevent every class
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from officiation that have been implemented fake
interface so how can you do it well for that go to
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your proguard-rules.pro and here add keep class I
mean all class that have implements our interface
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and the interface name is fake interface okay so
just clean your project and rebuild it all right
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so open up your build outputs mapping mapping. txt
and try to search first IML see this time it will
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use the same name first implementation similarly
if you are searching for second implementation
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so we have four places so let's see here you can
see second implementation is used as it is second
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implementation cool so now it's time to see how
we can protect our package that contains model
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classes from offis station so for that let me
create few classes within the model package so
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in this model package this scenario will be happen
when you want to get some information from backend
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on that case you have to create few model classes
that will match your Json and you will simply use
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Json converter Factory to convert your Json into
this model classes so in this case this model will
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be protected from offes station otherwise your
application sometimes will crash so let's see
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how we can prevent it so for that let's create
two data class and the data class name is model
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for first class okay so in this I'm simply passing
name naming string uh we have one more class and
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this time I'm going to name it model second class
wall name we have a string over here now it's time
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to use it so go to your main activity private wall
first and the class name is model first class and
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in place of name just type some JIS similarly
private while second model second class and in
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place of name I'm typing some JIS it's time to
use the first and second so here I'm using plus
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first plus second all right so now I want to
protect these two classes from offes station
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so let's see how we can do it for that open
up your progard rules. pro use here keep class
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mention your package name which is cor himansu
progard model dot use here two asri open a pair of
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parenthesis again use asri and semicolon so just
clean your project and rebuild it to see whether
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it is sistic or not okay open up your build
output mapping mapping. txt and try to search
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model first class okay so we are not able to
find it so find it like this way model first
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class KT here you can see model first class is
not offest stated it has the same name similarly
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we have model second class so let's see how we
can prevent some public function that present
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within a class so suppose in our main activity I'm
having a public function and and the function name
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is let's say my custom function so it has some JIS
variable cool and I'm using this uh function over
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here my custom function and I want to prevent it
from aestic only the public function that present
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within the main activity so how can you do it well
for that open up your pr- rule. proo use here keep
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class use your main activity and open a pair
of parenthesis use your public all public so
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for all you you should use here asri and
lastly a semicolon so what it will do it
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will simply prevent all of the member function
that present into your main activity which is
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public from off station so just clean your project
and rebuild it all right so if you want to see the
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function name my custom function in your
mapping. txd you can find it it's very easy
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it's not a big deal all right so now it's
time to execute this application in our
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emulator so for that we have to change our
built variant from release to debug it's a
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very simple project just execute it it will
work okay so this is the very basic project
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that's all for this video I hope you enjoyed
a lot it's a very important video because if
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you are not using PR guard and publish your
application into Play Store it will be very
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risky so don't do that so yeah that's it for this
video If you like this video subscribe my channel
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and also write your comments if you found
any problems or if you like this video we'll
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meet in our next video where we will discuss
something new about Android till that goodbye
