Unit 1

Introduction to Android
Android is a mobile operating system made by Google. It was first
released in 2008. It is open-source, which means anyone can use,
change, and share it for free. Android runs on many devices like
smartphones, tablets, smart TVs, and wearables (like smartwatches).
Because it is flexible and easy to use, both users and app developers like
it a lot.

Why is Android So Popular?

Here are the main reasons why Android is widely used:
1. Open-Source
o Android is free to use and can be modified by anyone.
o Developers can improve it and make new apps easily.
o There is a large community to help and support.
2. Large Market Share
o Most smartphones in the world use Android.
o Developers can reach a very large number of users.
3. Works on Many Devices
o Android can run on cheap phones, expensive phones, tablets,
and more.
o This helps reach all types of people – rich or poor.
4. Easy to Customize
o Phone makers and users can change how Android looks and
works.
o Apps can be made to work on different screen sizes and
hardware.
5. Google Services Built-in
o Android comes with apps like Gmail, Google Maps, YouTube,
etc.
 o Developers can use these in their own apps easily.
6. Multitasking
o You can run more than one app at the same time.
o This gives a better experience to users.
7. Developer Tools
o Google gives Android Studio, a free software to build apps.
o It has tools to test and fix apps easily.
8. Google Play Store
o It is the main place to download Android apps.
o Developers can share free or paid apps with people all over the
world.
9. Many App Types
o Android has apps for games, studies, work, chatting, and more.
o So developers from different fields create apps for it.
10. Security and Updates
• Android has improved its security.
• Google sends updates to fix problems and protect user data.

Conclusion
Android is a great choice for mobile app development because:
• It is free and flexible.
• It works on many kinds of devices.
• It has a huge number of users.
This makes it easier for developers to build apps and reach people
around the world.
History of Android (Simple Explanation)
1. Android is a mobile operating system that powers many smartphones
and smart devices today. But it started small and grew over time with
many changes and improvements.

How Android Started

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 • 2003 – Android Inc. was founded
A company called Android Inc. was started by Andy Rubin, Rich Miner,
Nick Sears, and Chris White.
At first, they wanted to build software for digital cameras, but they
soon decided to focus on mobile phones.
• 2005 – Google buys Android
Google saw a lot of potential in Android and bought the company in
2005.
After that, the development of Android became faster and better with
Google’s help.

Evolution of Android (Growth Over Time)

1. Android Beta (2007)
The first test version of Android was released.
Google also created the Open Handset Alliance – a group of tech
companies working together to support Android.
2. First Android Phone – HTC Dream (2008)
The first phone with Android was called HTC Dream or T-Mobile G1.
It had a touchscreen and a keyboard.
3. Android Market (2008)
Google created the Android Market (now called Google Play Store)
where people could download apps.
Developers could also upload their apps there.
4. Android 1.5 Cupcake (2009)
This was the first big update.
It introduced features like:
o On-screen keyboard
o Video recording
5. Android 2.0 Eclair (2009)
Added new features like:
o Multi-touch (using two fingers on the screen)
o Better performance and camera support

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 6. Android 4.0 Ice Cream Sandwich (2011)
Brought a new look (user interface),
o Face unlock
o Better multitasking
7. Android 5.0 Lollipop (2014)
Introduced Material Design – making apps look smoother and more
beautiful.
It made Android apps easier and more fun to use.
8. Android 10 and After (2019 onwards)
o Google stopped using dessert names (like Pie, Oreo, etc.).
o Added important features like Dark Mode, better privacy, and
more security.
o Android 11, 12, 13, etc., kept improving the system for both
users and developers.

Conclusion (In Simple Words)

Android started as a small idea but became one of the most popular
mobile systems in the world.
It is free to use, works on many devices, and lets developers create all
kinds of apps.
Because of its flexibility and support from Google, Android continues to
grow and improve every year.

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❖ Why Android is Popular for Mobile App Development
Android is one of the most widely used platforms for building mobile
apps. Here's why developers love working with it:

Key Features (in Simple Words)

1. Free and Open-Source
Android is open-source, which means anyone can use its code for free.
Developers can change it and create their own custom apps easily.
2. Huge Number of Users
Android runs on billions of devices around the world. So, if you make
an app for Android, it can reach a lot of people.
3. Works on Many Devices
Android apps work on many types of devices — from cheap phones to
expensive ones, tablets, smart TVs, and even smartwatches.
4. Google Play Store Support
Developers can easily publish their apps on the Google Play Store,
which is the main app store for Android users. It also helps with
updates and earning money from apps.
5. Great Tools for Developers
Android Studio is the official tool used to build Android apps. It has
features like smart coding help, testing tools, and more to make
development easier and faster.
6. Lots of Features to Use
Android has built-in tools (APIs) that let developers add things like
maps, music, camera, notifications, and more into their apps.
7. Multitasking Support
Android lets apps do many things at the same time. For example, an
app can download updates in the background while the user does
something else.
8. Easy to Customize
Developers can change how the app looks and works to match
different needs. This helps make unique and user-friendly apps.

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 9. Strong Security
Android keeps improving its security. It has features like app
permission controls and Google Play Protect to help keep users and
their data safe.
10. Helpful Developer Community
Android has a large community of developers. There are lots of
tutorials, forums, and help available online, which is great for
beginners and experts alike.

Conclusion (Simple)
Android is a flexible, powerful, and developer-friendly platform. It works
on many devices, has great tools, and gives you access to a huge
audience — which is why it’s one of the best choices for building mobile
apps.

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Main Components of the Android Platform (Easy Explanation)
Android is made up of different layers that work together to help apps run
smoothly on your phone. Let’s break down each part in simple words:

1. Linux Kernel (The Base Layer)

• Think of this as the heart of Android.
• It helps the phone talk to its hardware (camera, screen, battery, etc.).
• It manages memory, battery, and security in the background.

2. Libraries and Android Runtime (ART)

• Libraries are like pre-written tools in C/C++ that help with tasks like
playing music, showing graphics, and connecting to the internet.
• Android Runtime (ART) helps apps run faster. It changes app code into
something the device can understand and run quickly.

3. Application Framework (App Building Tools)

• This is a set of ready-made tools that help developers create apps
easily.
• It includes parts to manage the screen, messages, location, camera,
etc.

4. Applications (Top Layer)

• These are the apps you use — like WhatsApp, YouTube, or Phone
dialer.
• Some come built-in, and some are downloaded from the Play Store.

5. Activity Manager
• Manages what’s happening on your screen.
• Helps open and close apps, switch between them, and save your
progress in each.

6. Content Providers
• Let apps share data with each other safely.

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 • Example: The Contacts app allows WhatsApp to access your saved
phone numbers.

7. Broadcast Receivers
• These listen for system-wide messages like “battery low” or “new
message received.”
• Apps can use them to react to these changes, even when not open.

8. Services
• Services are like helpers that work in the background.
• Example: A music app can keep playing songs even if you open
another app.

9. Intents
• Intents are messages used to start another screen, service, or send
information.
• Example: Clicking “Share” on a photo uses an Intent to open sharing
options.

10. Permissions and Security

• Android protects your personal data by asking for permissions (like
camera or location).
• You choose what an app can access, keeping your device safe.

Conclusion (Easy)
The Android platform is made of several important parts — from the Linux
kernel (which controls the hardware), to the application framework (which
helps build apps), and the apps themselves. Each part has a role in making
sure apps work well, share data safely, and run smoothly on millions of
different devices.