Building an android
app is like solving a complex puzzle and it definitely brings smile to face.
Every stroke has its place, and each scene can turn into a breathtaking
masterpiece. Without some sort of plan, you could end up with a mishmash.
Design patterns to the rescue. This is a guide you should use when writing code
that tries to fit into any one of these patterns, which are blueprints for
efficient and scalable-albeit maintainable-code. Design patterns; a must know
for simple apps or multihued mobile architectures which can help you to build
robust, reliable and testable code on the front of development process.
Understanding
Design Patterns
Definition and
Purpose
What the heck are Design Patterns then? They are
some of the most tried-and-true solutions to common problems in software
design. They are generalised design solutions to common problems, which can be
further applied and used in the implementation. They are built with tested and
proven development paradigms as the intention is to accelerate the developer
workflow. That way your code will be stable and scalable with less chances of
bugs.
Types of Design
Patterns
Basically, design
patterns are of three types.
- Creational Design
Patterns: Deal with object creation mechanisms. - Structural Patterns: this category regards itself
with the likes of class or object composition. - Patterns of behavior: This family is responsible for
the interaction and responsibility of an object
Design Patterns we
use in Android Development
Model-View-Controller
(MVC)
Structure and Usage
The MVC is probably
the most popular design pattern. It breaks an application up into three
interconnected components:
- Model: Manages data
and business logic - View: To the user it is a output of data.
- Controller: intercedes between the View and
Model, interprets user actions to make calls at specified location of codes
in modelirectional, updates the view when clicks are made(ArrayList as well
updated everywhere here).
Advantages:
- Separation of concerns.
- Easier to manage and scale.
Disadvantages:
- Too complicated for simple applications.
- Controller and View tightly coupled
Model-View-Presenter
(MVP)
Structure and Usage
MVP is the evolution of MVC that takes separation of
concerns even further. It includes:
- Model: Same as MVC.
- Presentation: Similar to MVC but more passive.
- Presenter: The presenter is the middle tier which it
acts as a bridge between View and Model to manage all presentation logic.
Advantages:
- Projection cut of concerns than MVC
- Easier to unit test.
Disadvantages:
- Becomes cumbersome when we have the lots of
presenter classes.
Model-View-ViewModel
(MVVM)
Structure and Usage
MVVM is quite popular nowadays and pretty similar
with architecture of jetpack compose. It consists of:
- Model: Same as MVC and MVP.
- View: Same as MVC and MVP.
- ViewModel: Implementing the business logic
correctness, using correct data, else UI will be hanged and frozen.
Advantages:
- Encourages a clean separation of concerns.
- ViewModel is lifecycle-aware.
Disadvantages:
- Steeper learning curve.
- Might be overkill for small projects.
Behavioral Design
Patterns
Observer Pattern
How It Works
The Observer design pattern lets an object (the
subject) monitor other objects (observers) for changes in its state. Its
similar to a subscription service where subscribers receive updates whenever
there is new update.
Use Cases in Android
- Data binding.
- Event handling.
Strategy Pattern
How It Works
The Strategy Pattern specifies a series of
algorithms and selects one from among them. In simple terms, this allows the
objects behavior to change dynamically.
Use Cases in Android
- Sorting algorithms.
- Encryption strategies.
Creational Design
Patterns
Singleton Pattern
How It Works
Singleton pattern is one of the simplest design
patterns in Java. This type of design pattern comes under creational pattern as
this […] Some things come in handy, like managing shared resources as
databases.
Use Cases in Android
- Managing network connections.
- Handling shared preferences.
Factory Pattern
How It Works
The factory pattern, on the other hand, defines an
interface for creating objects but allows subclasses to control which class is
instantiated.
Use Cases in Android
- Instantiate View Models.
- Dynamically creating objects with user input.
Structural Design
Patterns
Adapter Pattern
How It Works
The Adapter pattern lets otherwise incompatible
interfaces to work together. It works as an interconnection with two
applications that are incompatible!
Use Cases in Android
- Including third-party libraries
- Recycler View Data Adaptation
Composite Pattern
How It Works
The composite structure allows you to build the
objects into tree structures, representing part-whole relationships between
group of objects. In this way, clients can treat both individual objects and
compositions identically.
Use Cases in Android
- Creating convoluted UI elements.
- Managing directory structures
Picking the Right Design Pattern
Factors to Consider
IdentifySuitable Verification Pattern For Given
Scenario
- Complexity of the projectBoom vs Bust
- Expertise of the Team: Knowledge on varied patterns
between team members. - Solution-Related Constraints: Some designs might be
a struct, which may introduce overhead
Link Patterns to Your Requirements
Do as much research as you need to have a grasp of
your project’s needs, and pick the design pattern that best suits this
requirements. If it does not seem natural do try to use a pattern.
Design Patterns Implementation Best Practices
Ensuring Code Quality
- Follow coding standards.
- Make sure your code is neat and easy to read.
- Continuously Re-factor your code
Testing and Debugging
- Exactly the same as write some code to implement a
function – every single case must be put into unit test. - Employ debugging tools to detect and correct
glitches
Case Studies
How design patterns are being used succesfully in
popular apps
Instagram and WhatsApp are two of the most famous
examples where we have design patterns in use for code quality and scalability.
One good example is WhatsApp that uses the Observer pattern to handle real-time
messaging.
Lessons Learned
- Using design patterns consistently can make code
more maintainable. - Design patterns when implemented correctly lends
scalability to the application.
The Future Trends of Android App Development
Evolving Design Patterns
Design patterns that have emerged over time as
Android development grows especially with Jetpack Compose and Kotlin.
Developers are changing their app structure with these new tools and
frameworks.
Impact of New Technologies
New architectural patterns emerging from
technologies like AI and machine learning are stretching old school app
development conventions.
