Android App Architecture
By - Godlin Josheela Rani S
Model View Controller (MVC)
- The view is directly coupled with business logic which is nothing but the controller.
- Adding new functionalities with existing code is complex as the view class file(Activity/Fragment) itself will have to hold nearly 1000+ lines of code.
- After performing business logic, the view has to be updated manually.
- Code understanding and hand over is difficult.
Advantages of MVC architecture:
- App Development is fast.
- Multiple developers can collaborate and work together easily.
- Minor changes in application can be update easily.
Disadvantages of MVC architecture:
- It is hard to understand for other developers to make changes in code.
- Must have strict rules on methods or else code maintenance will become complex.
Model View View-Model (MVVM)
- View and model are not connected at all.
- View model handles 2-way coupling. Once data is changed in the view model, the data automatically changes in the model and also view automatically.
- Code handover and understanding is easy.
- App performance will be improved as we do not have to update view manually every time.
- In MVVM pattern Android Jetpack libraries like Data binding, ROOM database, etc.. must be used for better usage of Live Observable data of View models.
Advantages of MVVM Architecture
- Application code is even more easily understandable than other architectures.
- Application code is further decoupled (the biggest advantage.)
- The package structure is even easier to navigate.
- The project is even easier to maintain.
- Development team can add new features even more quickly.
Disadvantages of MVVM architecture:
- It has a slightly steep learning curve. Understanding how various layers work together may take some time, especially when coming from patterns like simple MVC or MVP background.
- It adds a lot of extra classes, so it is not ideal for low-complexity projects.
- MVVM can be hard to design for the ViewModel up front in order to get the right amount of generality.
Notes for Architecture Migration MVC to MVVM
- Development time for MVVM is higher in comparison to MVC.
- Conversion from MVC to MVVM takes approximately the same time as developing a new app using MVVM pattern as the only reusable code from MVC will be the models.
- Conversion is more complex , Developers need lot of time to replace all components to Jetpack Libraries and Room data base.