Postaround

Postaround is a demo app which allows users to see Instagram posts in their area. At this time the app is in Sandbox mode, so user accounts will need to be approved in order to use the app.

The app will show users 10 posts from their area. A default radius of 500 meters around the users' current location will be used, with the option of extending the search radius from the app's UI.

Also, the app will automatically search a wider area if there are no results found near the user.

Preview

Demo

You can try it out here.

Screenshots

Running the app

1. Get the source code

Clone this repo to your PC and open it in Android Studio.

2. Build and run!

The project is ready to be built it and run on an Android emulator or your Android phone.

Using the app

1. Make you a Sandbox user

Since the app is only for demo purposes is in Sandbox Mode. It is, however, a fully functional environment that allows developers to test the Instagram API.

To make you a Sandbox user send me an email to jalejandro.hperez@gmail.com. After your account has been confirmed as a Sandbox user, you'll be able to start using the app.

If your account hasn't been enabled as a Sandbox user, the app will show a view similar to the image below.

2. Exploring the app

Now you're ready to explore the app! Sandbox users are by default from Miami, FL. If you are in Miami, you'll see some cool posts and your app will look like the image below.

If you aren't in Miami you will probably see only posts of yourself (if you tag the location in your posts). If you don't usually tag your location in posts, you'll likely see a screen like the one below.

Changing the radius setting

To set a custom radius to look for posts, click the ruler icon in the upper right corner of the screen (see image below).

A foreword to Unit Tests in the project

Before executing the tests it is important to know that I've used the Model-View-Presenter (MVP) pattern. The MVP pattern allows for greater code readability, testability, cleanness and adaptability to changes. To know more about MVP pattern check this article.

In the images below you can see how I've applied MVP to the Feed functionality for both cases when retrieving the data: Success and Fail.

Success

The Success case involves the following methods:

• subscribe(): Used to notify FeedPresenter that FeedActivity is ready to get the data.
• onRecentMediaStarted: Used to notify FeedActivity that the API request will start soon.
• getRecentMedia(...): FeedPresenter tells FeedDataSource to get the recent posts within a given radius around a specified location.
• onCompleted(): FeedDataSource has finished getting data from the server and notifies the FeedPresenter.
• onRecentMediaCompleted(): Notify FeedActivity that all the necessary data is fetched already.
• onNext(...): FeedDataSource returns the requested data to FeedPresenter.
• onGetRecentMediaSuccess(...): FeedPresenter returns the requested data to FeedActivity.

Fail

The Fail case involves the following methods that are not involved in the Success case:

• onError(...): FeedDataSource notifies FeedPresenter that an error occurred during the request.
• onGetRecentMediaError(): FeedPresenter notifies FeedActivity about the error.

Unit Tests included in the project

In this project I've implemented three tests:

• FeedPresenterTest.getRecentMediaShouldLoadIntoView: It checks that the View calls the right methods when the Presenter has requested the recent media and the response is successful.
• FeedPresenterTest.getRecentMediaShouldReturnErrorToView: This test is similar to the first one. The only change is the Presenter will get an error in the response and the View should trigger the appropriate methods.
• PrefUtilsTest.securePrefsAreSavedCorrectly: This test checks that the data is correctly saved by an external library used to securely persist the Instagram API access token across app sessions.

How to run the first two tests

Switch to the Local Unit Tests View in the file explorer in Android Studio (see the image below). You'll see a folder named app. Expand the folders under it until you get to a class named FeedPresenterTest. Right-click the class and select Run 'FeedPresenterTest'.

How to execute the last test

Switch to the Android Instrumented Tests View in the file explorer in Android Studio (see the image below). Expand the folders under the app folder until you get to a class named PrefUtilsTest. Then, right-click the class and select Run 'PrefUtilsTest'.

Instagram API

The main functionality of this app is supported by one endpoint of the Instagram API:

GET /media/search

Parameters

Name	Description
ACCESS_TOKEN	A valid access token
LAT	Latitude of the center search coordinate. If used, lng is required.
LNG	Longitude of the center search coordinate. If used, lat is required.
DISTANCE	Default is 1km (distance=1000), max distance is 5km.

Reference: Instagram Developer Documentation