Lecture Outline for Creating a Class 2 Android App

 

Creating a Class 2 Android app introduces more advanced concepts, such as connecting to the internet, handling more complex layouts, managing user data, and adding interactivity. Here’s a detailed lecture outline for developing a Class 2 Android app:

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Lecture Outline for Creating a Class 2 Android App

1. Introduction to Class 2 Android Apps

• Understanding Class 2 Apps
  • Class 2 apps involve moderate complexity and typically require more user interactions, some data management, and sometimes internet connectivity.
• Overview of the App Goal
  • For this lecture, we’ll create a News App that fetches and displays the latest news articles from an API, with search and filtering capabilities.
• Learning Objectives
  • Accessing a remote API, handling JSON data, building a more complex UI, and saving simple data.

2. Project Setup and Initial Configuration

• Starting a New Project
  • Open Android Studio, select New Project > Empty Activity.
  • Set the App Name, Package Name, and choose Language (Java/Kotlin).
• Required Permissions
  • Explain why internet permission is necessary for apps that access online resources.
  • Add <uses-permission android:name="android.permission.INTERNET" /> to AndroidManifest.xml.

3. Designing a Complex UI Layout

• Exploring RecyclerView for Dynamic Lists
  • Introduce RecyclerView (a more advanced version of ListView) to efficiently display news articles.
• Creating Layout Files
  • activity_main.xml: A RecyclerView to display articles and an EditText for search functionality.
  • item_article.xml: Define the layout for each article item, including TextView for the title, ImageView for the article image, and TextView for a short description.
• Using ConstraintLayout
  • Set up elements in item_article.xml with ConstraintLayout to control positioning and maintain a responsive design.

4. Fetching Data from an API

• Introduction to RESTful APIs
  • Brief overview of how REST APIs work and the concept of HTTP requests.
• Selecting an API for News Data
  • For this app, we’ll use a public news API (e.g., NewsAPI, or another free API).
• Adding Retrofit for API Calls
  • Install Retrofit (a popular HTTP client library for Android) by adding dependencies in build.gradle.
  • Configure Retrofit in a separate ApiClient class to manage API calls.
• Parsing JSON Data
  • Use Gson (Google’s JSON library) for parsing JSON responses into data objects.

5. Implementing RecyclerView and Adapter

• Setting Up Data Classes
  • Create a NewsArticle data class with properties like title, description, and imageUrl to represent each article.
• Creating RecyclerView Adapter
  • Create an ArticleAdapter class to bind each NewsArticle item to the RecyclerView.
  • Define onBindViewHolder to populate each article’s title, description, and image.
• Loading Images with Glide or Picasso
  • Use Glide or Picasso library to load article images from URLs directly into ImageViews in item_article.xml.

6. Handling API Calls and Displaying Data

• Making API Requests in MainActivity
  • Use Retrofit to fetch data from the news API in MainActivity.
  • Handle API responses asynchronously and update the RecyclerView adapter with fetched articles.
• Error Handling
  • Handle possible errors (like no internet connection) by displaying messages using Toast or Snackbar.
• Updating UI with Fetched Data
  • Once data is fetched and parsed, pass it to the RecyclerView adapter to display in the app.

7. Adding Search and Filtering Capabilities

• Implementing Search Functionality
  • Add an onTextChanged listener on the EditText for search.
  • Filter articles based on the user’s search query and update the RecyclerView with matching results.
• Improving User Experience
  • Show a loading indicator (like a ProgressBar) while data is being fetched.
  • Hide the loading indicator once the data is loaded or in case of an error.

8. Saving User Preferences (Optional)

• Using SharedPreferences for Simple Data
  • Save the user’s last search term using SharedPreferences so it persists even when the app restarts.
  • Retrieve the search term from SharedPreferences on app launch and automatically perform the search.

9. Testing the App and Debugging

• Testing on Emulator and Device
  • Test the app in different environments to ensure that it handles various screen sizes and internet conditions.
• Debugging Techniques
  • Use Logcat to monitor network requests, responses, and any errors.
  • Add breakpoints to check data at different points in the app’s flow.

10. Preparing for Launch and App Maintenance

• Optimizing the App for Performance
  • Consider options like caching images with Glide or Retrofit for smoother performance.
• Final Testing and Packaging
  • Test the app thoroughly, and ensure it handles edge cases like empty or slow responses.
• Creating an APK
  • Generate the APK by going to Build > Build Bundle(s) / APK(s) > Build APK.
• Publishing Options (Optional)
  • Overview of app publishing on the Google Play Store, including adding icons, screenshots, descriptions, and other requirements.

11. Q&A and Recap

• Recap Key Concepts
  • API calls with Retrofit, JSON parsing, RecyclerView, and image loading.
• Address Common Questions
  • Troubleshoot any challenges related to setting up the adapter, API requests, or data display.