Mobile Application Development I – SS2 Digital Technologies Lesson Note (Third Term)

A mobile application, or app, is a software program designed to run on a mobile device such as a smartphone or tablet. Apps usually do one or two things well, for example WhatsApp for messaging and Uber for transport. Developers can build them as native, web or hybrid apps, and they run mainly on Android or iOS.

Behavioural objectives

By the end of the lesson, students should be able to:

• define a mobile application and give examples;
• name the two main mobile operating systems and say who owns each;
• describe native, web and hybrid apps, with one advantage and one disadvantage of each;
• list four ways in which apps make money;
• state the five stages in the life cycle of an app.

What is a mobile app?

Think back 10 or 15 years ago. If you wanted to check the weather, play a game or send a message, you usually needed a big desktop computer. Today, we carry all that power in our pockets.

A Mobile Application (or “App”) is a software program designed specifically to run on a mobile device, like a smartphone or a tablet. Unlike computer software, mobile apps are usually built to do one or two things really well (e.g., WhatsApp is for messaging, Uber is for transport).

Which operating systems do mobile phones use?

Just like a car needs an engine to run, a phone needs an Operating System to manage its hardware. In the mobile world, there are two main “Bosses”:

1. Android (owned by Google): Used by many brands like Samsung, Tecno and Infinix. It is “Open Source,” meaning many companies can use it and change it.
2. iOS (owned by Apple): Used only on iPhones and iPads. It is “Closed,” meaning only Apple controls how it works.

Teacher’s note: These two systems speak different “languages”, so an app built for an Android phone will not work on an iPhone unless the developer makes two different versions.

What are the three ways to build an app?

When a developer wants to create an app, they have to decide how to build it. There are three main categories.

Native apps (the specialists)

These are built for one specific system using that system’s favourite language (e.g., Java or Kotlin for Android; Swift for iPhone).

• Pros: They are very fast and can use all the phone’s features easily (like the camera or GPS).
• Cons: You have to build it twice if you want it on both Android and iPhone.

Web apps (the pretenders)

These are not actually “installed” on your phone. They are websites that are designed to look like apps. You open them through a browser like Chrome or Safari.

• Pros: They work on any phone.
• Cons: They need the internet to work and cannot always use the phone’s special features (like the fingerprint scanner).

Hybrid apps (the all-rounders)

A hybrid app is a mix of both. Developers write the code once, and it gets “wrapped” in a way that allows it to work on both Android and iPhone.

• Pros: Saves time and money.
• Cons: Sometimes a bit slower than native apps.

How do the three app types compare?

How do apps make money?

Most apps on the Play Store are free to download, so developers earn money in other ways:

• Advertisements: Showing small ads at the bottom of the screen.
• In-app purchases: Charging for extra features (like buying “coins” in a game).
• Subscriptions: Charging a monthly fee (like Netflix or Spotify).
• Premium apps: You pay a one-time fee to download it.

What is the life cycle of an app?

Before you see an app on your phone, it goes through these steps:

1. Idea: Deciding what problem the app will solve.
2. UI/UX design: Drawing how the buttons and screens will look.
3. Development: Writing the actual code.
4. Testing: Checking for “bugs” or errors.
5. Launch: Putting it on the Google Play Store or Apple App Store.

Evaluation

1. Look at your phone. Name three apps that you think are native (for example, apps that came with the phone and work offline).
2. If you were to build an app for your school, would you make it native or web-based? Give one reason.
3. State two differences between Android and iOS.
4. List the five stages in the life cycle of an app.

Assignment

Activity: Draw a simple “Home Screen” for a new app that helps students keep track of their homework. Show where you would put the buttons.