Delve into Flutter's UI framework to build high-quality Android apps, from creating contact profiles to enhancing them with themes and API integration, culminating in app publication.

Flutter is Google’s mobile UI framework used for crafting high-quality native interfaces on iOS and Android. This course focuses on building applications for the Android platform.

You’ll start by exploring the intricacies of Flutter and work your way up to implementing a contact profile page for an Android address book.

In the latter half of the course, you’ll learn to work with Flutter themes to spruce up the contact profile app you created. To round out your Flutter experience, you’ll also practice fetching data from a remote Application Programming Interface (API).

You’ll put into practice what you learn using live coding environments embedded within the course. By the time you’re done, you’ll be ready to create your own Android app and publish it to the Google Play Store.

Salahaddin Mohammed

I completed the course "Beginning Flutter: Android Mobile App Development" at the Educative platform. I have easily understood the course because of your great explanation. I want to thank you really!

Thank you letter from a student.

Beginning Flutter: Android Mobile App Development

In this section, you’ll learn how to access [TMDB API](https://www.themoviedb.org/documentation/api) to fetch popular movies. 

# What is an API?

API is an acronym for Application Programming Interface. An API lets two applications talk to each other. 

The Movie DB contains information about popular movies and TV shows. API is the way to facilitate the app to fetch information from this big movie data storage into our application.

# API key

An API key is a unique identifier given to a user, app, or developer to be able to make API requests. It is used to track the number of requests made by the app.

In the code, we'll be using a variable `apiKey` to store the API key to access TheMovieDB API.

```
final apiKey = "YOUR_API_KEY";
```

First, you’ll need to get an API key for yourself. You need this to be able to make API requests to TMDB servers. Once you have your own API key, don't forget to replace it with "YOUR_API_KEY".

## Getting an API key
 
Follow these steps to request an API key from TMDB API:

* Create a free account [here](https://www.themoviedb.org/account/signup).
* Check your email to verify your account.
* Visit the [API Settings](https://www.themoviedb.org/settings/api) page in your Account Settings and request an API key. You should now have an API key and be ready to go!
* Update API key in code.


## Accessing API

Now that you have your API key, keep it safe & handy to use in your code later for "YOUR_API_KEY".

# Configuration

Flutter uses the [`http`](https://pub.dev/packages/http) Flutter package to make HTTP requests.

## Adding package in `pubspec.yaml`
 
Add this package under the `dependencies` section. Be careful about indenting `yaml` file:
```
dependencies:
  flutter:
    sdk: flutter
  http: ^0.12.0+1

```

## Importing the package

We'll be making HTTP requests from code to fetch remote movie data. To do so, we need the Dart's `http` package available to the code.

Import the `http` package in your code. Use the [library prefix](https://dart.dev/guides/language/effective-dart/style#do-name-import-prefixes-using-lowercase_with_underscores) `as` for readability.

```
import 'package:http/http.dart' as http;

```

# API endpoint

An endpoint is a place where the resource lives and where an API sends requests. Usually, an endpoint is a URL of the service.

The API endpoint or URL to request the [most popular](https://www.themoviedb.org/documentation/api/discover) movies is `/discover/movie?sort_by=popularity.desc`

> **Replace `YOUR_API_KEY` with your own key generated in last [lesson](https://www.educative.io/courses/beginning-flutter-android-mobile-app-development/calling-rest-api#getting-api-key)**.

```
final apiKey = "YOUR_API_KEY";
final apiEndPoint =
"http://api.themoviedb.org/3/discover/movie?api_key=${apiKey}&sort_by=popularity.desc";
```
Your endpoint is ready to make an HTTP request.
 

## Make HTTP Request

The package `http` imported earlier is used to make the HTTP request in the code snippet below.  

The `await` keyword is used to make network calls asynchronously without blocking the main thread.

The following code returns the API response of [`HttpResponse`](https://api.dart.dev/stable/2.7.1/dart-io/HttpResponse-class.html) type. Printing it will print a text string 'Instance of Response.'

```
import 'package:http/http.dart' as http;

final apiResponse = await http.get(apiEndPoint);
```


# Run code

At this point, we'll print `apiResponse` fetched from API. It'll simply print 'Instance of Response' on the screen.

> Look out for the //NOTE comment(s).

> Don't forget to replace `YOUR_API_KEY` with your own API key to make requests to the TMDB API.

> Please note that Android Emulator might take longer (~3 minutes) to start.


In this lesson, we cover calling REST API in detail.

Introduction

Hello Flutter !

Build your Contact Profile Page

Flutter Themes

MovieApp: Fetching Data from REST API

Where to Go from Here

Appendix: Installation & Setting up Flutter (Optional)

Calling REST API

What is an API?