App developmet slide

1. Lecture no. 12
Mobile Application development

2. Topics covered:
• Bloc
• Cubit
• River Pod
• Builder
• Future
• asycn
• Splash Screen
• Shared Preferences
• async*
• Future Builder
• Stream Builder

3. Bloc
It has three folders:
• bloc: Contains the business logic components.
• state: Contains the state classes representing the
various states of the application.
• event: Contains the event classes that trigger
state changes.
When an event is triggered, it initializes a state.
The bloc contains functions that handle these
events and manage the state transitions.

4. Cubit
Folders:
• bloc: Contains the business logic components.
• state: Contains the state classes representing the
various states of the application.
Purpose:
• Used as a simpler alternative to Bloc when Bloc brings
too much complexity.
Emit Function:
• Used in Cubit to emit new states and notify the UI of
state changes.

5. Riverpod
• Functionality:
– Acts like multi-threading, providing enhanced
state management capabilities.
– An enhanced version of Provider, offering more
features.
• Use Cases:
– Ideal for applications requiring instant state
changes, such as chat apps.
– Suitable for scenarios where request and response
handling need to be synchronized.

6. Builder
Used to conditionally wrap other widgets based on a
condition.
• Usage:
– Conditional Rendering:
• The Builder widget is used to conditionally render parts of the UI
based on certain conditions..
– Dialog Creation:
• By using the Builder widget to wrap a widget tree that includes an
AlertDialog or SimpleDialog, developers can easily create dialogs
that pop up over the main UI.
– State Management:
• The Builder widget can be used to manage state within a specific
part of the widget tree, allowing for more granular control over
state changes and updates.

7. Future
• In Flutter, a Future function is one that runs
first in a sequence of functions. For example, if
there are five functions and the fifth function
is a Future function, it will run first.

8. async
• An async function in Dart is a function that
performs asynchronous operations.
• It contains only one Future function and uses
the await keyword to pause execution until
the Future completes.

9. SplashScreen
A splash screen in Flutter is a screen that appears for a
short period when an app is launched.
• It includes an initState method that runs first when the
app is opened, allowing for initial setup.
• The Future.delayed function can be used within
initState to introduce a delay before loading the main
content, useful for showing branding or introductory
animations.

10. Shared Preferences
Shared Preferences in Flutter is a storage
solution for small amounts of data, similar to
how WhatsApp backs up chat history.
• Storage:
– It utilizes the device's storage, including libraries
like sqflite and Hive.
As it deals with a single entity, there's no need
for complex loading operations.

11. async*
• An async* function in Dart is used to create a
stream of values asynchronously.
• It can contain multiple Future functions,
allowing for the generation of multiple values
over time.

12. FutureBuilder
• Functionality:
– Used in Flutter to load and display data asynchronously.
– Requires specifying the data type expected from the
Future, especially important when using Firebase.
• Builder Method:
– The builder method of FutureBuilder must return a widget.
– It has two parameters: context and snapshot.
• Snapshot Parameter:
– Provides the state of the connection, indicating if the data
is loaded or if there's an error.
– Helps manage UI based on the state of the asynchronous
operation.

13. StreamBuilder
Used in Flutter for building UI based on stream data,
suitable for real-time updates like chat apps.
Preferred over FutureBuilder for chat apps to avoid
frequent loading.
• Usage:
– Specifies the stream using stream: APIClass.getData();,
with datatype required for Firebase.
– In the builder method, var data = snapshot.data; is used to
access the data.
– Data can be directly used or processed using a model
approach, which is considered better for organizing and
managing data.