I'm trying to implement this multi-module design on my app, the thing is that I'm thinking about create an "api" or "network" module where I create the retrofit instance (I'm using Dagger2, but it doesn't matter, if you have an example or pseudo with any other DI framework feel free).
Problem?
I've been working on an app that I had this similar architecture but it ended up with a big module because I had organised the instance of a retrofit and then inside of it a sub-packages with each feature where I have the services and the responses.
This helped me with a problem that I had for instance, use the same service on a different features.
Example
Home feature I need to call the Feature1Service to show X
Feature1 need to call Feature1Service to show more stuff
I've thought with a solution that instead of creating the api or network module create every service inside of that feature, but doing this is a problem.
So I'd like to listen options or if you have worked with that app with modules how did you do that?
Short question
How do you use on multi-module project where you share services between features? (Retrofit)
Related
I am building a library that every 30 seconds displays a question (obtained from a REST Api) and allows the user to select one of the possible answers.
Also, I need to make use of that library in an app, displaying a video underneath the question.
Desired result
All the business and UI logic should be handled in the library.
Does it make sense to use an MVVM approach, with repository pattern in the library?
With this package structure?
Possible package structure
You're creating the library, which is totally different context and way of creating the codebase comparing to the app.
First of all you need to make decisions about the dependencies. Of course it is super easy to put retrofit, mvvm and other dependencies into the app and manage them further.
With library it's not that easy. What I would expect from library in the first place is to have as little dependencies as possible. If you're going to provide aar file, then the developer would have to include those dependencies in the project. On the other hand, if you're publishing the library to maven repo, the gradle will take care of the library's dependencies. However the biggest challenge here is maintaining the library and resolving conflicts in actual app that uses the library. It can lead to frustration and eventually someone can throw your library away, which is the worst thing from library creator's perspective.
What I would suggest for this small library (calling api and providing data to custom view) is to:
Use only OkHttp without retrofit to provide the data from the REST api.
If it's the case for the library, create some abstraction over the OkHttp client with public functions/methods so the developers can get the data by themselves. Cool approach for creating this kind of interface is to use Fluent Interface (for example if you want the client of the library to put their access token/secret key for the REST api to detect who is calling the api, how much, limit their requests etc)
If you want to also provide the Custom View I would suggest to think twice about separating the REST client and Custom View itself and let the developer put the data by themselves. On the other hand if you want to handle it by yourself, you have to consider error handling, state management, lifecycle callbacks for cancelling the requests etc. You can provide some Listener interfaces for the developers so they know what is going on in the custom view.
The way you structure the library is up to you, if you have only one dependency (the rest client) just pass the objects via constructor so you won't need to add another dependency. Or just simply use ServiceLocator pattern, however it should also be connected to the Application/Activity itself when setting up the library so the objects are destroyed properly
I want to implement Room database in my app, but I want to do that by creating a Library project.
Library project will store data
Android project will have the Objects and Dao's
Is this possible?
For this I have to implement Room in both Android project as well as Library
But can I have Dao's and Objects in Android project and Database in Library
Why I want to do this.
I want to build this feature in a generic way so that it can be used in my other project. Also Library will not just store the data, it will have some offline functionality which read a Offline data table and checks the internet connection and picks data from the table and send it to server.
None of this is implemented yet. I am in the process of thinking what is the right aproach
Thanks for your suggestions
R
It's a great desire to move Room to the separate module as far it's Android specific and violates the principle of the Clean Architecture. Here is where you can start, at least it looks similar: another stack question and take a look at all the answers.
About re-usage, probably, it will be quite hard. Not sure, that time you spend to make it universal be less than when you implement it in each project. So, take the time in the account also.
The case where it makes sense.
At my company, we did the next. We have a few related products (a few apps) that have similar user-intended logic. So we have a library that takes care of all user login / token expiration logic and so on and it provides a simple interface for the app to handle user account. Single code base, useful when fixing bugs. And connect this library to each project as a general module. But still, each app has its own internet communication and database because of domain-specific data.
The best for testing and architecture - move all room and internet logic to the module in the app. Access it by interfaces. You can share that module between apps.
I think you can use dynamic feature module, because it dependency to the app module and you can use Dao and Objects from app.
I'm trying to understand what structure should have a multiplatform library. Checking on the Internet I've seen a huge number of examples explaining how to make a log or a "hello world" but there's a lack of complex examples, even in the official documentation (important to note that I'm only interested in mobile platform, iOS and Android).
So I want to create an example that simply opens the camera (as a lib, not as a multiplatform app) just to have an idea of how to work with a real feature which, also, is native. Right now I have created a project following the official example, so it has a common module (using expect) and one for Android and one for iOS (using actual), and now these are my doubts:
I've seen that the iOS module is also in Kotlin, Kotlin/Native as I understand. Should my project have also an wrapper in Swift, or will the library have no Swift code? And if it should, where should it be in the project structure?
Also in the Android module I've noticed I cannot import the class "Activity" nor the "Intent", which I will need to open the camera, why? is this code restricted to Java without the Android libs? Should it also have a wrapper to Android? If so, how can I configure this wrappers?
I know I can use the "expect" key when creating classes but, as I understand, the common and the native modules will always be separated classes. I mean, if I create a class in the common module, can I define methods of this class using "expect" and define them later in the native?
Can my lib have a Manifest?
Finally, does anyone knows a real example that really explain a more complex situation?
Thanks
Okay, let's go through your questions one-by-one.
I would recommend you to have a look at this example
The
iOS module produces an Objective-C framework as a result. It can be utilized by the Xcode project the same way as any other framework with non-Kotlin origins.
It looks like the unavailability to use
Android SDK is the result of using jvm("android") target instead
of android() one. To use the android target, one has to apply the android Gradle plugin in addition to kotlin-multiplatform one.
I
think you want to do something like that: just ordinary class
declaration in the common and extension function for it with an
expect modifier. And then actualize it in the platform-specific
code.
I think so.
I'd also recommend you to have a look at
this and this, maybe these examples will be complex enough for you.😁
Am working on a huge android project that has more than 50 APIs request
and using the MVVM pattern, My question is:
can I add all the requests in the same app repository or I must create a repository for each service?
As others suggested in the comments you should first define the modules of your app and then create the corresponding Repositories. This way you can easily maintain and test your application.
I strongly suggest you to have a look on this https://github.com/nickbutcher/plaid and mostly this video https://youtu.be/Sy6ZdgqrQp0
A good solution to this problem is, You must not implement all your API calling code to the same repository as it will become a massive single repository class. It will also be violating design principles i.e. rule of 30 as you are saying you have at least 50 APIs to work with.
Also, it is not a good practice to modify a class, again and again, see Open Close Principle.
You can make multiple API calling classes under the same package name.
I’m working on a project that is based on the GithubBrowserSample demo application that’s on the Android Architecture Repo on Github.
So far, I was able to inject dependencies to my App, activities and fragments and ViewModels. Also I was able to add more Modules; right now I use two, one for Shared preference and the other a NetModule that has all the mumbo jumbo related to Retrofit/OkHttp.
But here’s the catch: currently the demos that I found that shows how to implement the Retrofit/OkHttp module has a static base URL, which doesn’t work for me since that information is available until the User provide it on the Login section…
Digging around I found that one solution is to create a Submodule (StackOverflow post) with a given Scope Instantiate the component inside my Activity/Fragment. But because I’m using Dagger 2.11 for Android to perform the injection, I have no idea how to do so…
Is there an example that I can look around, or should I give up on this path and take the OkHttp interceptor to change the URL?
Thanks in advance.