Installing and Removing Apps

Installing and Managing Mobile Applications

Installing an App from Google Play Store

  • Platform Overview: The Google Play Store offers a vast ecosystem of mobile applications. While many apps are available free of charge, others require purchase prior to installation. To utilize any application on an Android mobile device, it must first be downloaded from the Play Store.

  • Step-by-Step Installation Process:

    1. Locate and Open Play Store: Tap on the Play Store Icon on the mobile device home screen.

    2. Search for Application: Type the exact name of the application (e.g., Duolingo) into the search bar located at the top of the screen, then click or tap the search icon/button.

    3. Select Application: Locate the target application from the search results list (e.g., Duolingo: Learn English Free) and tap on it to open its details page.

    4. Initiate Installation: Tap on the green Install button.

  • Downloading & Completion:

    • The system automatically initiates the download and installation process, displaying real-time progress indicators (such as showing memory percentage and download size like 28% of 18.80 MB alongside an option to Cancel).

    • Additional details visible during download include user ratings (e.g., 4.6 stars from 11M reviews), app download package size (e.g., 19 MB), content badges (e.g., Editors' Choice), and age rating (e.g., Rated for 3+).

    • Once installed, the application icon appears directly on the mobile device screen, ready for launch.


Installing an App from Google Play Store UI

Removing an App from a Smart Phone

  • Rationale for Removal: Every installed application consumes internal device storage space. It is essential practice to uninstall or remove applications that are no longer in active use to recover and free up internal device memory space.

  • Step-by-Step Uninstallation Process:

    1. Tap the Settings icon on the mobile screen.

    2. Tap on the Apps option within the settings menu.

    3. Tap on the Manage apps option.

    4. Select the target application by tapping directly on its icon (e.g., Duolingo).

    5. Tap on the Uninstall icon/option at the bottom of the screen.

  • Result: The selected application, along with its installation files, will be completely removed from the smart phone.


Removing an App via Settings UI

Mobile App Development Fundamentals

Key Considerations Before Developing an App

  • Open-Source Software: A wide variety of open-source app development software platforms are available to help construct custom mobile software.

  • Core Design Principles:

    • Uniqueness: The central concept or core idea of the planned application should be unique and distinct.

    • Relevant Features: The software must incorporate all pertinent functions and features required to solve its targeted user problem.

    • User-Friendliness: The graphical user interface and operational logic should be intuitive, accessible, and user-friendly.

Introduction to App Inventor

  • Definition & Provider: App Inventor is a free, web-based mobile app development environment provided by the Massachusetts Institute of Technology (MIT). It was originally created and developed by Google.

  • Core Capabilities: App Inventor empowers creators to construct functional applications for Android smart phones using a web browser in tandem with a connected physical phone or an integrated device emulator.

  • Programming Style: The developmental mechanics of App Inventor are closely modeled after the Scratch programming language. Instead of writing text-based syntax, developers assemble applications using visual drag-and-drop block components.

  • Primary Operating Views:

    • Design View: The visual layout layout tab containing all physical and non-physical UI components (such as buttons, labels, and text boxes) necessary to design the application interface.

    • Block Editor View: The logical scripting tab where graphical programming blocks are connected together to execute rules, event handlers, and application logic.

Setting Up and Initializing App Inventor

Account Prerequisites & Authentication Workflow

  • Prerequisite: Developers must possess an active Gmail / Google account to authenticate and use App Inventor.

  • Step-by-Step Account Setup:

    1. Navigate to Portal: Launch a web browser, enter the URL https://appinventor.mit.edu, and press the Enter key.

    2. Access App Engine: On the home interface, click on the Create Apps! button.

    3. Provide Username: On the Google authentication overlay ("Sign in to continue to App Inventor Authentication"), type your full Gmail username/address into the input box.

    4. Proceed: Click on the Next button.

    5. Provide Password: Enter your Google account password in the secure password field.

    6. Authenticate: Click on the Next button.

    7. Accept Terms: Review the prompt presented by the MIT Center for Mobile Learning regarding service rules, Google's App Engine platform, and Creative Commons Attribution 4.0 International license (CC BY 4.0). Click on the I accept the terms of service! button.


Setting up MIT App Inventor and Google Sign-in flow

Creating a New Project

  • Step-by-Step Project Initialization:

    1. Click on Continue on the initial welcome announcement overlay.

    2. Click the Close button on the welcome tutorial splash dialog window.

    3. Click on the New project button located on the top navigation toolbar to start your first application.

    4. In the popup titled Create new App Inventor project, enter your chosen name into the Project name: box (e.g., HelloClass). Note that system settings like Toolkit default to Default and Theme defaults to Device Default.

    5. Click on the OK button to establish the workspace.


Starting a new project in App Inventor

Workspace Panes and Building a Talking App

Architecture of the Project Designer Window

Upon creating or opening a project, the Project Designer window opens. This interface is structurally divided into four specialized functional panes:

  • Palette Pane: Positioned on the far left side of the window. Contains categories of functional UI elements including buttons, images, labels, text input boxes, layout containers, and media tools required to build the app.

  • Viewer Pane: Positioned directly to the right of the Palette pane. Features a central white smartphone screen mockup where components selected from the Palette pane are placed and visually arranged.

  • All Components Pane: Situated towards the right side. Provides an organized, hierarchical structure of every component attached to the active screen. Includes drop-down filter controls to view All components, components, or Non-visible components.

  • Properties Pane: Located on the far right edge. Selecting any component inside the Viewer pane populates this section with its configurable parameters (e.g., width, height, text content, color, background patterns), allowing detailed custom settings.


Project Designer Window layout and 4 panes

Creating a Talking App

  • Interface Construction: The Project Designer window allows developers to craft application interfaces by combining interactive controls (such as buttons and text boxes) with specific underlying code logic.

  • Adding a Button Component:

    1. Locate the Palette pane on the left side under the User Interface group.

    2. Select the Button component.

    3. Drag and drop the Button directly from the Palette pane into the mockup screen inside the Viewer pane.

  • Testing the Live Application:

    • App Inventor supports live interactive testing during the creation process without requiring full app compilation.

    • To test an application on hardware, click on the Connect menu in the top application header bar.

    • Establish a live mirror link by downloading and opening the MI A12 companion (MIT AI2 Companion) application on an Android mobile device.