Make Your Code Clean With the SOLID Principles
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- Опубліковано 7 лют 2025
- Writing clean code gets more and more essential the bigger your projects get. The SOLID principles help you do that.
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0:00 Introduction
0:51 Find problem with existing code
1:36 S = Single Responsibility Principle
4:05 O = Open Extensions, Closed Modifications
7:09 L = Liskov Substitution
9:43 I = Interface Segregation
11:31 D = Dependency Inversion
Great explanation with a simple to understand example. Amazing videos as always.
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finally , now i understand why interfaces are so important ,I struggled so much to find reason to use them , Thank you philipp
Same here
Me too... I knew what an interface is in general, but not what it really means in coding (at least I had a bright moment)...
Play the video in 2x speed then you'll be learning SOLID in 10 minutes
But you will understand 2x less as well
@@feepin2058 not necessarily
Lmao
So scary 😂
Writing code is simple but writing simple code is difficult. Good work Philip, it helped me to learn SOLID principles 😅
Experience is so freaking important!.
6 months ago, i saw this video i didnt understand anything of it.
Now i understand everything! Because without knowing, i used all of this on my job, day to day on Android.
Excelent!
Now going for theory behind design patterns
Hi!) I am from Russia and I am learning English to find a job in another country. You have good English I understand almost everything and your videos help me to learn the language))
This is simple AF , nobody showed this important principle with this level of simple and easy examples ! Take a bow @Philipp
For Interface segregation principle; I think we shouldn't create a function (that sometimes needed and sometimes not) - printLogs() function in this video - inside the same interface, We should create another interface and declare this function in it and if we need this functionality we can implement this interface and plus other interfaces like FileLogger interface in this video
Agree! But the video still is amazing.
You're right
That's what I thought. Apart from that, video was good.
Yeah! I did note that and agree with your response!
Also agree. If I have an instance of FileLogger and call printLogs(), I'd expect it to print the logs, but it won't. Moving the printLogs() to a separate interface such as LogPrinter, would make more sense.
In example for open/closed, you treated the FileLogger class as being completely closed. Your CustomFileLogger was effectively another implementation of a FileLogger interface. It is ok to add new functionality to the FileLogger class, for example adding another function called timestampedError(), as long as you do not change the logError() function it adheres to the open/closed principle. All existing consumers of FileLogger will work exactly as they did before.
For your example of Liskov substitution, the CustomErrorLogger class does not violate Liskov substitution. All instances of FileLogger can be replaced with CustomErrorLogger and will work exactly the same. This is because all calls to logError() will still go to the base FileLogger via inheritance.
Your explanation is great. But, I have a question here, we already have a function named logError() in class FileLogger. So if we add timestampedError() to FileLogger it is not violating single resposibility principle? Kindly help me understand better
@@avigneswaranwaran well ... first of all timestampedError is not a good function name IMO. I follow the pattern of naming a function with a verb prefix. That, plus vonn didn't say what that function does makes it hard to know what vonn intends that function to do. But ... if that function is about logging to a file (logs a timestamped error?) then it does adhere to single responsibility (SR). Then again, vonn's comment is about Open/Closed (O/C) ... why are you asking about SR?
Thank you for your content Philipp! It helps so much and I'm glad there are developers who strive to make code as good as possible!
Vielen vielen Dank lieber Philipp für diese tolle Erklärung. Du hast da wirklich ein Talent solche Dinge sehr einfach für jeden verständlich zu machen.
Liebe Grüße aus Österreich.
Been binge watching all your recent videos. Amazing Android content 👏🏽 👌🏽
I got goosebumps when he said, "This changes the entire implementation in one line of code. 🦋"
This is programmer porn
What a nerd 💀
awesome man. I didn' like you previously when seen on interviews but Now addicted to how you teach and how humble you really are.
You have such a nice way of explaining things brother. Keep making these videos please. Thank you.
I would've killed for this video when I first started learning Android and programming; Thank you.
The video we didn't ask for, but really needed..
For the optional interface function, you could also do = Unit instead of the empty function braces.
Yea sure was just a quick demo here
@@PhilippLackner I think you must do make separate interfaces for every method. So you can use multiple inheritance for every method you need. Because function with empty body standing in the interface not a good case that much.
I finally understand them now, I faced the same problem when searching them online...very hard to understand. This was waaay easier to understand. Thank you!
Glad it helped!
I watched this video after watching your multi module course. So clearly explained .. I clearly understand why you inject abstractions using hilt instead of concrete implementation ..... Thank you so much Philip
Thankyou Philipp, your way of explaining the issues through examples is just amazing. Thankyou for this great video.
This is a most important video in the internet for devs today. It's not easy to explain this topic the way he did. Kudos @Philipp
Best video about SOLID I've ever seen
Thanks for the explanations with easy examples 👌👏
This is literally one of the best channels out there. I can’t believe that I only found it now. I love the videos. Keep them coming!
P.s- would love to see a video about Alarm manager in Kotlin! Looking for such a video for a while.
The best explanation I have ever seen. Great job
Thank you so much dear philipp for record this courses ,
I just wanted say i love you ❤️😘
Bro, you are my new superhero, much much better than any other fictional superhero
I think a more appropriate example of Liskov substitution principle would be if an overriden function were to do something unexpected and contrary to its implementation in the base class. This can be shown with a base function that changes the state of the class which is overriden by a function that doesn't call the super method. The example provided doesn't break this principle. I liked the other explanations.
This is by far the best SOLID video explaining these complex SOLID software principles !! Thank you for this amazing content !!
The thing that I liked about the video was not wasting my time to learn this SOLID buillshit. Thanks for summarizing.
really the most informative explanation of SOLID principles. appreciated and thanks a lot man:)
Kudos Philip. This explanation was easy to grasp
Philip God bless you soooooooo much.... i can't thank you enough
After watching this last night I went back and re-watched Bob's playlist on clean code... outstanding!
Then today in a long term project interview (We interview internally for projects) I was asked, 'what are the SOLID principles of good software engineering?'
I played it cool,
.. 'fools, little do you know Phillipp just schooled me on this shit'
... barely had the words come out of my mouth when the hiring manager said "wait you know Phillipp?" ;)
Joking aside, the synchronicity is insane man, thanks so much for everything!
Haha thanks Matt! :D
I like how you explain complex things so easy👍nice
Simplest and best example with clean examples just like your clean codes @Philipp ! Awesome :)
This guy does it again!!! Nice explanations.
Glad you like them!
Just the thing I needed.
Surely will start using all these principles in my future projects.... Thanks bro...
Thanks for this video man!, Big fan of your channel
This is really helpful,some tutorial only targets output without considering clean code,thanks Philipp
Glad you liked it
So realy clearest explanation ever and simple practical
Thank you Philipp
Thanks mate!
You explain like Indians ❤ simple and easy to understand with examples.
Thanks a lot for that awesome explanation!
This guy is really good.... Keep it up bro
Keep making such videos.👍 It truly helps a lot.😌 Thank you 🙏🙂
Really amazing video
Thank you so much for clear explanation of SOLID 🙏
Well done video. Just pay attention to interface segregation. Interface segregation does not mean that clients do not need to implement the entire interface. It means that you should segregate different functions under several interfaces, and then it's up to the client to decide which interfaces to implement. I don't think the example here was demonstrative of interface segregation.
agreed, thanks for the feedback!
Probably onClickListener and OnLongClickListener are examples of it. Those 2 could be in a single interface, but that way you would have forced the class to implement these 2 methods even you want to use either of them.
Great video Philipp, would be awesome if you would cover more of these advanced topics. Keep up the good work!
Thank you it was very simple and easy to understand
Thank you for the explanation I learned something new today
Nicely and simply explained
Amazing video, I have studied the SOLID principles and I have never understood them so easily, congratulations, greetings from Caracas, Venezuela
Please make more videos like this !
thanks' a lot Philipp, appreciated your efforts
You got some perfect communication skills
Thanks ❤️
@@PhilippLackner Great video. I do have one doubt regarding auth in Dependency inversion. If we call auth.signInWithEmailAndPassword(), then which would be called among the functions in FirebaseAuthention and CustomApiAuthentication classes?Thanks in advance
@@satyasaineelapala570 you have to pass authenticator object while creating instance of Repository, if you've passed firebaseAuthenticator then it'll use that, and vice versa
@@mrwhoknows Thanks
Thanks man. Really helpful.
This videos was so helpful. Thank you
I liked explanation, Thanks! but Interface segregation principle is not explained properly. It states that, should have kept printLogs method in different interface and then can be implemented in classes wherever required.
Great content. You made it clear for me. Thank you so much.
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Thank you so much.
If possible also make a video on Design Patterns 😅
need to watch some more time. Thanks a lot
thank you mr philipp
Excellent bro !
Didn't realize I already did all of it long time ago.
Hey Phillipp we need more videos on clean architecture, if possible please make a playlist on it. I will buy that playlist if it is paid but please make that playlist
Am I crazy or did you not instantiate any of the class member objects that you are calling methods from. Still trying to get the hang of kotlin coming from java.
I do not understand why we need separate authenticator interface for Firebase. We already have an abstraction for repository and we can simply create another implementation with another dependencies. Why to double abstractions there?
do you have an example of project with clean arhitecture?
Repo is dependent on FirebaseAuth object which is wrong, Should be asbtracted and repo should also be abstracted with separating out implementation, and separate class for logging code.
saw videos about this topic and this helps me to understood it better.
easy to undertand also for stating with solid and why use it
half of the video after that i lost
I think the explanation for open for extension but closed for modification was a bit confusing.
I hope I'm understanding correctly that by modifying you mean adjusting functionality in pre-existing functions that already work fine.
thank you very much , this is really awesome
I always enjoy your videos. Would u do one video on adding time and date in an android studio app
Thanks I do that in a bunch of my Playlists
Please Make A Series About Clean Architecture...
Perfection!
Thank you!
Finally found a Bible for SOLID.❤️🙏
Great explanation man! Thank you!
Sir, u are the best!
it is good, but I need the new version of this video ... if you have a chance to do it.
Thanks. Very good explanation.
Very good video. One question regarding the Open Closed Principle: If I would create method for changing the path e.g.: open fun getPath(){...} Does this violate the principle?
Really awesome explanation 😐😐👏
Thanks bro!
With these vdo, I've understood what SOLID is.. Will you make a playlist making another project following MVVM, SOLID, Jetpack Compose etc... it would be nice
Planned for future yes, but not a specific date yet
@@PhilippLackner would love it if it comes ASAP.. maybe some app related to sports ....
Can you please make video on Important design patterns for Android developers?
Thanks in advance.
Very good presentation
... but off the mark on several aspects. I think you did well on S and D.
5:10: "we don't want to affect our whole code with just one change" Cannot disagree more strongly. This is exactly what code should be written to enable. Maybe you misspoke.
Open/closed principal does not strictly imply subclassing. It's a more general concept. It's about factoring the code so that one does not need to modify it as time progresses. Let's say I have a class that supports communications with a device that supports 10 commands. Later, the device adds support for an 11th command. I should not need to modify my existing classes to support that 11th command. The design should be such that I add a class to support the 11th command. This is a common design, right? We often see a class that supports something today and then needs updating when that thing is updated. In fact, such a class does satisfy the single-responsibility principle and it's a common design pattern. But, it's not good since it requires mods as time progresses. The OCP is about writing code one time and then never modifying it! And that is a foreign concept for most developers. We think: I can always change it in the future. But, the goal is to _not_ change it. To get the classes right and then use them like lego blocks. Not to keep re-engineering each lego block.
The liscov breaking example does _not_ break the principle. I can use the subclass just like I use the superclass. Total missed that one. An example would be to override logError and to do something other than log an error.
Interface segregation: it's about clients depending on things it doesn't need; not on subclasses implementing things that don't apply. Miss. Actually, your example for dependency inversion is also a good example for interface segregation.
I think you are covering some useful coding issues, techniques and common problems. But not covering SOLID very well.
Nice explanation on very complex and ambiguous topic. 👍👍 Plus i think we can do diff approach for interface segregation instead of giving default implementation.
Well, guess I'll be here for the rest of my college, bout to dive head first into android dev.
Awesome video!!
great material, very helpful, thanks !
Thanks philipp
Hey Philipp , What about MVI pattern?Can we have any tutorial on it. Thanks
Make video on this also please Phillip
Superb!!
For the open-closed principle, would you then be violating it if you provided a default parameter with the file path name, so that one could change the output location without extending the original class? Not sure if that's what you mean by closed to modification
The Liskov example is incorrect, because the child class still implements the parent class's method and still serves as an appropriate substitute. In this example the child class fails to implement it's own method, but still successfully fulfills the parent class method.
awesome man👍
Iam developing an app in java ..in that navigation drawer menu items are not getting clicked and not opening sir help as soon as possible
On the single responsibility principle example, shouldnt the error handling part be implemented in a different class? I mean it sounds and would look weird, but in principle this class still has more than one reason to change: 1. if we want to change how the user sign-in network call is implemented 2. if we want to change how the error handling works. I mean the logging part is in another class, so if we want to change only the error logging than everything is good, but if we want to change what gets called in the catch block in the first place than the class would have two reasons to change.
Somewhere you need to catch the possible exception. I think there is no other option to handle exception like writing try-catch in the same function. If you find some solution please share that might help to understand more. Thanks
You are the best 👌
Brilliant content