Udacity Android Nanodegree Project THREE submission
The project aims is to create an application for master baker Miriam to share her recipes with the world. Users will be able to select a recipe and view a video-guided steps to guide them through the process. They will also be able to add ingredients to a shopping list .
Full rubric can be found here
As a requirement, this project is written using only Java.
The application retrieves the baking data from a single endpoint with the following schema:
[
{
"id": 1,
"name": "",
"ingredients": [
{
"quantity": 2,
"measure": "",
"ingredient": ""
},
…
],
"steps": [
{
"id": 0,
"shortDescription": "",
"description": "",
"videoURL": "",
"thumbnailURL": ""
},
…
],
"servings": 0,
"image": ""
},
…
]
See full JSON response in this here
All the data requests and consequent response parsing is done asynchronously with the use of the Retrofit library
A single request is made to the Baking endpoint at the application startup. The data is deserialiased and stored in a local database. No further network request are made throughout the application lifespan.
The data received from the Recipe Service Request is persisted in a local SQLite database The database has a structure with the following tables:
- Recipes - holds data about recipes.
- Ingredients - holds data about the recipe ingredients. The table has a one-to-many relationship with the recipes table which is enforced with the use of a foreign key referring back to the recipe that ingredient belongs to.
- Steps - holds data about the recipe instruction steps. The table has a one-to-many relationship with the recipes table which is enforced with the use of a foreign key referring back to the recipes that it belongs to.
- Shopping - holds data about the ingredients in the shopping list. It has a one-to-one relationship both with the ingredients table and the recipes table which is enforced with the use a double foreign key referring back to these tables respectably.
The data is made available to the rest of the application with the implementation of a Provider. The BakesContentProvider supports the following actions:
- insert : recipes, ingredients in shopping table
- bulk insert : ingredients, steps and ingredients in shopping table
- delete : deletes ingredients from the shopping table
- query: all tables
A outer join selection statement is used to query data of the ingredient present in the shopping list. Ingredient details are gathered from the ingredients table every time a ingredient is present in the shopping table.
The provider also implements a technique where it registers its interest to database changes and notifies them to the ContentResolver so that the loaders are notified as soon the changes occur.
The application follows the master-detail view pattern consisting of three views:
- Master view showing a list of recipes. This is implemented in the MainActivity.
- Details view showing the ingredients and step instructions of the recipe selected in the master view. This is implemented in the RecipeDetailsFragment. The steps list is in itself a Master View where a step can be selected.
- Recipe step details view showing a video and description of the step instructions. It is implemented in the StepVideoFragment.
As part of the project requirements, the app implements a adaptive design where the recipe details and step instruction details are shown as part of the same view when using a tablet in landscape orientation. The default journey shows these two screens as a two distinct views as it can be above
The recipe list provides different layouts for the different screen sizes. It shows one column for small devices, two columns for tablet portrait and 3 columns for tablet landscape.
As said,
two
pane
layout is use in tablets
while
in
landscape orientation. This involves a transition from StepVideoActivity to
RecipeDetailsActivity when rotating from portrait. In this case, the app makes
sure to keep state and shows the same instruction step in both activities after the
transition.
The user could add any ingredient to a shopping list while browsing a recipe. Ingredients can be added individually by selecting the ingredient itself. An option menu item is provided to add / remove all recipe ingredients at once.
When an ingredient is added or removed to/from the shopping list, the user is prompted with a message. Also any ingredient in the shopping list will appear highlighted in the recipe ingredient list.
The project uses version of the exoplayer library version 2.6.1. This was the latest version at the time of production. This is a different version from the one used in the examples and required a different implementation to the one shown there.
The player provides a simple and easy to use interface where the instruction video can be easily paused while in the process of following a recipe. The player starts immediately as soon the step is selected. Video playback can be paused and restarted by touching anywhere in the player. The video restarts playback from the beginning when the user touches the screen after the video is ended.
The SimpleExoplayerView’s controls have been customised so that to only show the progress of the content. Any other functions have been removed. The controls shows a timebar and two text views for this purpose.
The player provides the following feedback to the user:
- buffering
- video is paused
- video is finished prompting the user to reply video
- current progress of the video
At a implementation level, the player doesn’t make used of a MediaSession due to its scale. One player is created per fragment that is instantiated. The player is released when the fragment is detached from its activity. Error handling is not implemented at a UI level at this stage.
The application has a companion homescreen widget which displays a ingredient list for any of the recipes available.
Selecting any of the ingredients listed in the widget will open the selected ingredient recipe where the ingredient could then be removed/added from the list.
The widget displays a message when the shopping list is empty. Selecting this message will open the app at the main activity (recipe list)
The project includes unit test for the request and parsing of the data. It also provides unit test for the database and model classes.
The project provides Espresso tests for the MainActivity: MainActivityTest
In order to assist to these tests a idling resource, a view assertion and customised matchers have been implemented
The Parameterized runner is used to run these tests with a set of values
This is a list of the external libraries use in the project as requirement:
For a list of support and other Android libraries, see the build.gradlefile