Pagination from Remote API & Local Cache Using Paging3, Compose and Clean Architecture
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- Опубликовано: 27 ноя 2024
- In this video you'll learn how you can use Paging3 in Jetpack Compose together with clean architecture.
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9:15 "Personally I prefer to just have my own solution"
Yesh!! in a project of mine, I had to fetch new list of url from server on reaching every 30th image (27 actually).
I implemented my own `paging` by using the `position` value from `onBindView()` of ListAdapter.
I did that after hearing your words 🥰
because of you I found out that I don't need Paging library 💯
Philipp, great course! Thank you for uploading & sharing!
Wanted to mention, to avoid exposing your BeerEntity to UI layer, consider separating cache/caching to its own db.
i.e. BeerEntity becomes BeerCatalogItem (this is the cached entity in its own DB). You can always include more extension functions / mappers to get a clean Domain object out to UI layer.
Pros:
- simplicity in caching
- simpler schema migration
Cons:
- another DB
- more space for cached content
Awesome courses! Thank you again! (Will buy one soon to support you!)
I have a problem with the domain layer interface, PagingSource and its data layer implementation because dao in the data layer requires PagingSource. As I know the domain layer should not contain data layer entities, how to implement the domain layer interface in the data layer?
I was waiting for the exact Tutorial on this channel.... And here it is. Philipp is just amazing
Happy to help!
In 20:12 I would change endOfPaginationReached logic to 'endOfPaginationReached = beers.size() < pageSize' which will save us one extra refresh at the end of the list
thank you boss.. I remembered contacting you on your instagram DM on this topic.. and here we are.. God bless you greatly.. really appreciate you...
Happy to help!
Thank you very much for the live coding tutorial.🙏 It's simple, easy to understand, and very rewarding.
Thank you Philipp for the tutorial,
Your mediator loads 4 pages (80 beers) at startup before scrolling
How did you solve this? It happens in my implementation too?
@@reyjohn88 didn’t solve yet
At 21:19 the Paging Library pollutes the ViewModel with Entity. Would the use of a Repository help here? The Repository could expose LazyPagingItems to the ViewModel, and it is ok for Repository to know about Entity.
thank you
helped me overcome a couple of obstacles i was encountering
This tutorial is an artwork😊 thanks Phlipp
Thank you so much! It helped me to get the json file. But I’m dealing with json that contain two object first is information about current page, next page url and previous page url and another one is list with the objects that I want to display in recycle view. What should I do? Do I need a data class for each object?
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If you have page size 10, and already have 2 pages loaded, and there's 29 beers in list, following will happen:
- paging lib loads page 3
- entities count is 29
- next page = 29 / 10 + 1 = 2 + 1 = 3
- end of pagination not reached
- paging lib loads page 3
- upsert updates last 9 items
- back to start
Great tutorial, once again.
I am wondering if we can wrap the pager inside a repository, or, even, an use case and then inject these in our viewmodel, what do you think?
Great as always and so amazing tutorial. Keep doing such useful videos!
I enjoyed the video. But I noticed that in the data package, there is a remote mediator that makes the API call and has some business logic. Does the remote mediator replace the repository and the use case at the same time when referring to clean architecture?
Suggestion, an app with a shared view model for a basket, and some payment method. Philip you rock
Great video, Thanks Philipp 👏
Violation of clean architecture principal but video is good❤
Awesome video Phillip, as always. 👏🏾
If you wanted to group the data into different sections, how would you go about doing that?
Awesome! it was a good introduction to Paging
Thanks for this perfect explanation!
Glad it was helpful!
Punk API stopped working, getting 404
Same here
you just make everything simple
My daily dose of Android Stuffs
It would be awesome if you can make a CRUD operations with Paging 3
I always make mappers as `val` extensions. Are there any disadvantages of this solution?
Hi Philipp. First of all, thank you for this amazing tutorial. I have a question. What if I need to update the paging list? For example, update some item at position. How can I achieve this?
Hello Philipp, thanks for the amazing videos. I have a question, let's say I'm fetching some data from the api and want to keep it somewhere that multiple viewModels can reach. But I don't want to fetch the data again every time it needs to be used. What is the best way to do it without breaking the clean architecture? Which layer of clean architecture I should keep them? Should I keep the variables in a companion object (I don't want it) or maybe in a repository and inject that repository to the viewModels that need to use it. I don't want to use a BaseViewModel also because I have so many of those variables :) thank you.
In this, I notice that the pager calls API for 3-4 pages on app startups. And I also want to include that when the app needs new data on scrolling that time also it calls API for 2 pages at a time. Can we manage it to call API only one time at a time?
Thanks for the video, you probably got there by now but at 21:27 to solve this (if I understood correctly), instead of having the pager inside your viewModel, you can have another class in between like a dbRepository or a useCase or both. In that repository/usecase you return a Pager(...).flow.map(), and in there you map the PagingData items to your UI model.
Good video, but you should also include with cursor pagination logic, as it's the superior pagination type.
Thank you for the great video! If the description of the beer is long, I want to center the beer image on the card, can you tell me how I can center it?
Philipp, thanks for your brilliant work! It would be interesting to know how to remove the item from the list by item's id without refreshing the whole list? Looks like it is difficult to implement using compose paging3 library...
@PhilippLackner please create and add blog about this topic.
thank you phillip
Nice job. Thank you!
I think there is one more condition when `endPaginationReached` could be `true`. It's `state.config.pageSize` > beers.size().
It means that we got fewer items than we should have on the page and it was the last page.
Keep up the great work!
How to cache the images? Do you think you would cover the same?
Hi Phillip, Great Tutorial, Learning a lot.
I had a question, is it possible to get the total item count fetched till the current time in RemoteMediator?
I wanted to understand a use case when id is not exactly the number of items fetched?
LazyColumn items not showing LazyPagingItems choice. What am i missing? Can someone help?
I have same issue unfortunatelly. Did you manage to fix it?
This guy is amazing
thanks , amazing works great ,
can you also share your experiences on using markdown in compose
Thanks for this great tutorial! One question: why you are using retrofit and not ktor?
Hi Philip， Can you explain the relationship between PagingSource and RemoteMediator
Hi Philipp, I am trying to list out all the items available in Firebase Storage, cache and display it. It doesn't seem to work and I am stuck. What should I do? By the way, your videos are amazing and any video I need on Android Development, I come to this channel first and I mostly get the answers. Great work!
Hello Philipp, I would like to know about all of your courses. Is there a discount available if I purchase all of them?
Great. Thanks a lot
Thank you
It might be not the right question, but I really want to know which theme are you using in your Android Studio?
xcode-dark
@@germenwongthanks for reply
hello philip
always thank you for the video
Usually, external API and internal room data are often used in the structure of viewmodel - usecase - repository - dao, but why not use that structure when using paging?
Thank you for the video
Can you please make a tutorial about how to write back navigation that also supports also api 33? Because after api 33 there is someting new and it's really hard to find on the internet how to implement it perfectly.
Anyone trying this in 2024, the PunkAPI has been shut down. Just spent 2 hours on this for it to not work.
Thank you so much. I have a doubt. Why didn't you include the "androidx.room:room-runtime:$room_version" dependency? Isn't it necessary?
Philipp, at 31:50 in the video you select "items(items: LazyPagingItems", however it does not appear for me in the list. No matter what I select
I get an error when hovering over (beers) that states Type Mismatch Required: Int, Found: lazyPagingItems . This also happens if I use the app source code from the Github site. Could the problem be that I am using Android Studio Flamingo | 2022.2.1 Patch 2
You can use any other items()
items(beers.itemCount) { index ->
val beer = beers[index]
...
}
I also encountered the same problem，
You can modify according to the pagination library version of the video, and then
Amazing!❤
Hey Phillip - good stuff! You were down on Paging library one year ago and actually had an excellent tutorial video showing how to do it yourself. What changed your mind about Paging Library?
I still use it, but many people wanted a paging tutorial and if you page with a cache it makes things a lot easier
How Phillip you find these types of algorithms 17:25
Thank you. Will be pagination for KMM?
Hi Philipp, thank you for great tutorial. In the latest version of compose, LazyColumn items() function can no longer accept LazyPagingItems as an argument. What is the best way to solve this issue?
items(beers.itemCount){index - > val beer = beers[index]}..Use this
Or just use itemsIndexed
Philipp why you still use retrofit? I thought you said you love ktor more and prefer it
thanks for video!
Using entities instead of UI models in ViewModel is unacceptable. You made it short so that people wouldn't get bored watching the video, but we could have done this in the Repository layer.
Yes but why
I didn't get can u explain?
I wonder to imagine what happens to the loaded page if in the middle scroll we change the API query?
I can't find the items of lazypagingadapter
How to handle query situation? my project works with no query, how to make the paging based on query params?
Amazing
If I need to pass more parameters to remote api, like for example, if a user can select a parameter to filter the api responses, where do I pass those filter values for them to get to the api?
on your repository inside remote mediator pass
query String
fun getAllUsers(
query: String
): Flow {
val pagingSourceFactory = { database.userDao().getAllUsers() }
return Pager(
config = PagingConfig(pageSize = ITEMS_PER_PAGE),
remoteMediator = UsersRemoteMediator(
api = api,
usersDatabase = database,
query = query
),
pagingSourceFactory = pagingSourceFactory
).flow
}
on your remote mediator
lass UsersRemoteMediator(
private val api: HomeScreenApi,
private val usersDatabase: UserDatabase,
private val query: String
) : RemoteMediator() {
******
}
Great 👏
After going through different other articles and codebases, I have found that you cannot abstract out the database details from the ui layer, the pager object tightly couples the ui layer to the paging3 library.
If anyone else found a solution to this please tell
Hi Mr lackner . Can you teach crashlytics?
Can I use it with firestore?
I implemented this in one of my project, but don't know why it always loads first 4 pages everytime the screen loads. Anyone have any solution for that?
i have a question about pagination. Can u use it for all APIs or does the API have to be built in a way that supports it before you can use it?
The API needs to support it
@@PhilippLackner lets say the API does not support it, saving the unpaginated response to room and paginating from room is the right way to go?
@@amateur_gamer101 has a little impact but the longest time is needed to do the network call, not to load from the local db
❤
Will the courses be delivered to me like physically or I'll get them online
It's all online
Great
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Nice,
The deployment could not be found on Vercel :)
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Thanks for this video👏👏👏👏👏👏👏🙏🙏🙏🙏👍👍👍💪💪💪💪💪💪💪
Nice Vid but in the end it still an overhead to implement pagination and also from Archi perspective, I would not use it, and still not using it because of this.
done an' dusted!
it's not clear at all why there should be both Beer model and simple Beer data class that looks exactly the same. and what is this beer.tobeerentity and vise versa for? you don't explain crucial things..
It would be awesome if you can make a CRUD operations with Paging 3