App Development

1. Platform Dependency: Native Apps are built specifically for a single operating system (Android or iOS only); Web Apps are platform-independent and run on any operating system inside a web browser.
   2. Programming Language: Native apps use native compiled languages (Kotlin/Java for Android, Swift for iOS); Web apps use web technologies (HTML5, CSS3, JavaScript).
   3. Hardware Device Access: Native apps have full access to physical hardware (camera, GPS, accelerometer, fingerprint sensors); Web apps have very limited or no access to low-level hardware.
   4. Installation & Offline Use: Native apps are installed from the App Store and can function offline; Web apps require no installation but cannot function without an active internet connection.

• UI (User Interface):
1. Refers to the visual, graphical presentation and interactive aesthetic elements of the app.
2. Focuses on visual design: color schemes, button shapes, fonts, icons, layout grid spacing, and animations.
Question asked: "Does the app look modern, beautiful, and visually polished?"
• UX (User Experience):
1. Refers to the overall feeling, ease, satisfaction, and efficiency a user experiences while interacting with the app.
2. Focuses on logical user flow: intuitive navigation, speed, and how effortlessly a user can accomplish their goal (e.g., ordering food in 2 clicks).
Question asked: "Is the app easy, seamless, and satisfying to use?"

1. Ideation & Requirement Analysis: Brainstorming the app's purpose, identifying the target user audience, and defining required features.
   2. Wireframing & Prototyping (UI/UX Design): Sketching screen blueprints, user navigation flows, and interactive mockups.
   3. Coding & Development: Writing front-end client interface code and integrating back-end cloud databases, authentication, and APIs.
   4. Testing & Quality Assurance (QA): Testing the app for bugs, security vulnerabilities, battery drain, and responsiveness across various screen sizes.
   5. Deployment & Publishing: Submitting the finalized application package to the Google Play Store or Apple App Store for public download, followed by continuous maintenance.

• MIT App Inventor: An open-source, web-based educational visual programming platform developed by Google and MIT that allows beginners to create fully functional Android mobile applications using visual drag-and-drop programming.
• Designer Window:
The visual layout workspace where developers drag and drop user interface elements (Buttons, TextBoxes, Labels, Images) and non-visible components (Sensors, Camera, TextToSpeech) onto a simulated smartphone canvas.
• Blocks Editor:
The programming workspace where developers assemble interlocking graphical jigsaw puzzle blocks to define the app's logic, events, and mathematical behaviors (e.g., setting what happens when a button is clicked).

• Event-Driven Programming: A programming paradigm in which the execution flow of the application is determined by external user actions (events)—such as clicking a button, tapping a touchscreen, swiping, or sensor inputs like shaking the phone or receiving a text message.
• Example:
In a mobile calculator app, the code does not run sequentially. It waits idly until the user triggers a touch event on the "+" button (Event), which immediately executes the specific addition routine (Event Handler).

• Hybrid App: A mobile application that combines elements of both native and web apps. It is written using a single cross-platform codebase (HTML, CSS, JavaScript) that is wrapped inside a native shell container, allowing it to be installed from app stores and access hardware features.
• Two Popular Frameworks:
1. Flutter (developed by Google, uses Dart language).
2. React Native (developed by Meta, uses JavaScript).

1. Touch Target Size: Interactive buttons and links must be large enough ($> 48\text{ pixels}$) to be tapped easily by adult human thumbs without accidentally clicking adjacent buttons.
   2. Visual Hierarchy & Contrast: Important action buttons (like "Buy Now" or "Submit") must have high color contrast and prominent placement.
   3. Minimalist & Clutter-Free Layout: Keep screen text concise, avoid dense walls of text, and use clean whitespace to prevent cognitive overload.

• Role of Sensors: Sensors allow mobile applications to interact dynamically with the physical external world by detecting environmental changes, orientation, motion, and spatial location.
• Two Common Sensors:
1. Accelerometer / Gyroscope: Detects device tilt, acceleration, and shaking (used in mobile car-racing games and fitness step-counting apps).
2. GPS (Global Positioning System): Detects precise real-time geographic coordinates (used in navigation maps and ride-hailing apps like Uber).