Application Developmet lecture for backend
- 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.