Programming of Mobile Systems

Version 7.0

📝 Task

1. Add functionality to save downloaded data from the network to the repository (SQLite Database).
2. All data downloaded from the network must be saved in storage.
3. Modify the data loading mechanism to display in the table of entities and image collection as follows:
   • the request is first executed at the appropriate URL, as implemented in version 6;
   • if the data is successfully received, it is stored in the repository and used for display;
   • if the data from the network is not received or an error has occurred (the response status code is not 200, there is no Internet connection, etc.), you must try the received data for the request from the repository:
     • if the data from the repository is successfully obtained, it is used for display;
     • if the data is not in the repository, you must display a message that it is impossible to obtain data for the specified request.
4. Add cached images that are downloaded, so that if you want to re-display the image, it is not downloaded from the network, but obtained from the image cache.
5. For example:
   • the user launches the application for the first time with an existing Internet connection;
   • on the screen of the list of entities the user enters a query in the search field;
   • data is successfully downloaded from the network, stored in storage and displayed in a table;
   • the user deletes the query from the search field;
   • an empty list is displayed;
   • the user turns off the Internet connection on the device;
   • the user enters the same query in the search field;
   • when downloading data from the network, an error occurs because there is no Internet connection;
   • there is an attempt to obtain data from the storage;
   • since there is data in the storage for the query, they are displayed in the table;
   • the user enters another query in the search field;
   • when downloading data from the network, an error occurs because there is no Internet connection;
   • there is an attempt to obtain data from the storage;
   • since there is no data for the request in the storage, a message is displayed that it is impossible to obtain data for the specified request;
6. The same should be implemented for the image collection.

📙 Implemantation

1. This version has added the functionality of downloading data from the network to the repository for the two main tabs in the application - book search, image search.
2. When you enter the screen with a list of books, an empty list of entities is displayed, if you enter a query in the search field, the list of entities from the network for this query is loaded and displayed.
   • The download occurs if at least 3 characters are entered in the search field, otherwise an empty list is displayed.
   • When you click on a cell in a table with a list of entities about books, a form with complete information about the book from the network is loaded.
   • When you slide to the left, the entity is deleted.
   • If the data is successfully received, it is stored in the storage and used to display, if the network connection is lost, if the data in the storage is missing, a message is displayed that it is impossible to obtain data for the specified request.
3. Images downloaded from the network are cached and also stored in the local database as a link to their actual location on the phone.
4. When you enter the screen with a list of images, an empty list of entities is displayed, if you enter a query in the search field, the list of images from the network for this query is loaded and displayed. Uploading occurs when at least 3 characters are entered in the search box, otherwise an empty list of images is displayed. An image grid was designed according to the variant. When you click on the image, a form is downloaded with complete information about the image from the network (likes, saving, views, image size, number of downloads). It is also possible to download images to your phone.
5. In the absence of an Internet connection, images are searched by available image tags (taken from JSON), if something similar to a search query is found - the image will be displayed in the image grid, when you click on the image you can view full information about it.

🎥 How It Works

📷 Screenshots

        

 

        

Version 6.0

📝 Task

1. Add functionality to download data from the network for the contents of the last two tabs in the application (list of entities, detailed information about the entity, image collection).
2. Modify the logic of displaying the list of entities in the book search tab:
   • when entering the screen, an empty list of entities is displayed;
   • if you enter a query in the search field, you must download a list of entities from the network for this query and display it;
   • the list should be loaded only if at least 3 characters are entered in the search field, otherwise an empty list should be displayed;
   • The URL for retrieving data is https://api.itbook.store/1.0/search/REQUEST, where REQUEST is a query from the search box.
   • add an activity indicator animation when loading data.
3. Modify the logic of the screen display with complete information about the essence:
   • when you click on a cell in the table with a list of entities, you must download complete information about the entity from the network and open the screen where this information will be displayed;
   • The URL for retrieving the data is https://api.itbook.store/1.0/books/IDENTIFIER, where IDENTIFIER is the identifier of the corresponding book (field isbn13 from the essence of the book)
   • add an activity indicator animation when loading data.
4. Modify the logic of displaying the image collection on the image tab:
   • when entering the screen, an empty collection of images is displayed, then you need to download a list of images from the network and display it;
   • Use the following URL to retrieve data: https://pixabay.com/api/?key=API_KEY&q=REQUEST&image_type=photo&per_page=COUNT, where API_KEY - 19193969-87191e5db266905fe8936d565, where REQUEST - “hot + summer”, COUNT - 24
   • add an activity indicator animation when loading data.
5. Please note that it is possible to enter non-Latin letters or special characters in the search field, so you need to provide a situation so that the application handles it correctly.

📙 Implemantation

1. In this version, the functionality of downloading data from the network for the content of the last two tabs in the application (list of books, list of images) has been added.
2. When you enter the screen with a list of books, an empty list of entities is displayed, if you enter a query in the search field, the list of entities from the network for this query is loaded and displayed. The download occurs if at least 3 characters are entered in the search field, otherwise an empty list is displayed. When you click on a cell in a table with a list of entities about books, a form with complete information about the book from the network is loaded. When you slide to the left, the entity is deleted.
3. When you enter the screen with a list of images, an empty list of entities is displayed, if you enter a query in the search field, the list of images from the network for this query is loaded and displayed. Uploading occurs when at least 3 characters are entered in the search box, otherwise an empty list of images is displayed. An image grid was designed according to the variant. When you click on the image, a form is downloaded with complete information about the image from the network (likes, saving, image size, number of downloads). It is also possible to download images to your phone. The Picasso library was used to cache images and upload them efficiently.

🎥 How It Works

📷 Screenshots

        

 

 

        

 

Version 5.0

📝 Task

1. Add new tab to the app. The screen of this tab will display a collection of pictures.
2. Each cell in the collection will display an image. The width of the collection should be equal to the width of the screen, the contents of the collection are scrolled vertically.
3. Make it possible to display images in the collection that the user will select from the system image gallery. Add a button (or any other control) that, when clicked, opens the view controller, which represents the system image gallery. After the user selects an image, the view controller representing the system image gallery closes, and the image is added and displayed in the collection.
4. Grid for the location and relative size of collection cells:

  

📷 Screenshots

        

 

Version 4.0

📝 Task

1. Expand the class created in the previous work that represents the model entity: add new fields to the class.
2. Add a new screen that displays complete entity information. When you click on a row of a table with a list of entities, a screen should open with complete information about the corresponding entity (complete information about the entity is read from the files).
3. Add a search box to the entity list screen. After entering the query, you must display a filtered list of entities. You can filter on any field of the entity. In the example at the end of the document, filtering occurs by entity name. If the filtered list is empty, you must display a message to that effect.
4. Add a new screen to add a new entity to the list. When creating an entity, use only the base fields that are required to display in the entity list. Remember to validate the fields: for example, the year (for a movie) and the price (for a book) can only be numeric. The created movie essence must be added to the existing list and displayed in the table.
5. Add functionality to remove an entity from the book list.
6. Make sure you can start the project and that everything works correctly.

📙 Implemantation

1. In the previous work it was decided not to go the easy way, but to complicate the task and JSON file with book data was downloaded from the server via HTTP-request, but in this work this approach was inconvenient, so reading JSON-files was done from a folder. At the same time, the general architecture has not changed much, the previous implementation will remain on further versions, where it will come in handy. But you still need the Internet to upload images, because they are taken from Imgur.
2. A new screen has also been added to display the full entity information that opens when you click on a row in the entity list table.
3. Added search box to the screen with a list of entities. After entering the query, the result is displayed as a list of entities filtered by the title of the book. If the filtered list is empty, a message is displayed.
4. Added a new screen to add a new entity to the list. When creating an entity, fields such as title, subtitle, price, isbn, rating are used. Required fields are title and price. The ISBN may be blank, but if the user wants to enter it, he must enter 13 digits, no more, no less. Price is checked for correctness. The created essence of the book is added to the existing list and displayed in the table.
5. Added functionality to remove an entity from the list of books by swiping left.
6. Therefore, all the necessary functionality was added and tested, and the code was carefully documented and the purpose of each method, class, variable was described.

🎥 How It Works

📷 Screenshots

        

 

Version 3.0

📙 About

In this version it was necessary to add new tab and to download the corresponding archive with files, add files to the project.

Subject area - Books.

Next, create a class that represents the model entity of a particular subject area (Book). Add the appropriate fields and initializers to the class.

In this implementation, the JSON file with the data about the books is downloaded from the server via HTTP-request, the functionality for this, as well as for file parsing is registered in the class BookJSONParser.

The application also checks if the device is connected to the Internet and responds accordingly. The result of the request is checked for a failed response from the server or its absence.

The network call takes place outside the thread of the user interface using AsyncTask. ListView is populated with information from the JSON response. In the absence of data for display the application shows TextView with the corresponding message (No books to display).

If the connection is successful, all the necessary data will be displayed on the screen. The code was carefully documented and the purpose of each method, class, variable was described.

📷 Screenshots

   

 

Version 2.0

📙 About

In this version, it was necessary to create a second tab for the application, which displays the views in which drawing is implemented. The views show:

• graph of function drawn on points;
• drawn ring pie chart.

At one point in time, one of the two images should appear on the screen. We also needed to add a control to change what is currently displayed on the screen.

My task was to implement the function y = cos(x) on the interval x ∈ [-π; π] and a pie chart ring with sectors occupying the appropriate percentage of the circle and having the appropriate color: 45% (blue), 5% (purple), 25% (yellow), 25% (gray).

The graph output has been improved and in addition to the graph output cos(x) the corresponding interpolation function is output (used by Newton's polynomial).

The user can also select the number of points and boundaries on the x-axis, if the user does not select anything, the default values will be used, namely: on the x-axis (-π, π), the number of points - 10.

ToggleButton is implemented with animation, when switching to another position, the slider flows into the appropriate corner. Pie Chart is highlighted when the appropriate area is selected, and can rotate clockwise or counterclockwise.

📷 Screenshots

       

 

        

 

Version 1.2

📝 Part 1

The first part of the work is to perform certain tasks with a list of students. Code for the task is here.

Tasks and Solutions

Example of a student list

students_str = "Дмитренко Олександр - ІП-84; Матвійчук Андрій - ІВ-83; Лесик Сергій - ІО-82; Ткаченко Ярослав - ІВ-83; " \
              "Аверкова Анастасія - ІО-83; Соловйов Даніїл - ІО-83; Рахуба Вероніка - ІО-81; Кочерук Давид - ІВ-83; " \
              "Лихацька Юлія - ІВ-82; Головенець Руслан - ІВ-83; Ющенко Андрій - ІО-82; Мінченко Володимир - ІП-83; " \
              "Мартинюк Назар - ІО-82; Базова Лідія - ІВ-81; Снігурець Олег - ІВ-81; Роман Олександр - ІО-82; Дудка " \
              "Максим - ІО-81; Кулініч Віталій - ІВ-81; Жуков Михайло - ІП-83; Грабко Михайло - ІВ-81; Іванов " \
              "Володимир - ІО-81; Востриков Нікіта - ІО-82; Бондаренко Максим - ІВ-83; Скрипченко Володимир - ІВ-82; " \
              "Кобук Назар - ІО-81; Дровнін Павло - ІВ-83; Тарасенко Юлія - ІО-82; Дрозд Світлана - ІВ-81; Фещенко " \
              "Кирил - ІО-82; Крамар Віктор - ІО-83; Іванов Дмитро - ІВ-82"

Task 1

Fill in the dictionary where:

• key - group name;
• value - sorted array of students belonging to the appropriate group.

Solution

students_groups = {}

for student in students_str.split("; "):
    st_info = student.split(" - ")
    students_groups.setdefault(st_info[1], []).append(st_info[0])

for i in students_groups.values():
    i.sort()

print("\tTask1 1:\n", students_groups)

Task 2

Fill in the dictionary where:

• key - group name;
• value - dictionary, where:
  • key - a student who belongs to the appropriate group;
  • value - array with student grades (fill the array with random values using the randomValue function).

Solution

points = [12, 12, 12, 12, 12, 12, 12, 16]


def random_value(max_value):
    r = randrange(6)
    if r == 1: return ceil(max_value * 0.7)
    elif r == 2: return ceil(max_value * 0.9)
    elif r == 3 or r == 4 or r == 5: return max_value
    else: return 0


student_points = {}

for group, students in students_groups.items():
    student_marks = {}
    for student in students:
        student_marks[student] = [random_value(points[i]) for i in range(len(points))]
    student_points[group] = student_marks

print("\n\tTask 2:\n", student_points)

Task 3

Fill in the dictionary where:

• key - group name;
• value - dictionary, where:
  • key - a student who belongs to the appropriate group;
  • value - the sum of student grades.

Solution

sum_points = {}

for group, students in student_points.items():
    marks_sum = {}
    for student, marks in students.items():
        marks_sum[student] = sum(marks)
    sum_points[group] = marks_sum

print("\n\tTask 3:\n", sum_points)

Task 4

Fill in the dictionary where:

• key - group name;
• value - the average grade of all students in the group.

Solution

group_avg = {}

for group, students_marks in sum_points.items():
    avg = sum(students_marks.values()) / len(students_marks.values())
    group_avg[group] = avg

print("\n\tTask 4:\n", group_avg)

Task 5

Fill in the dictionary where:

• key - group name;
• value - an array of students who have >= 60 points.

Solution

passed_per_group = {}

for group, students_marks in sum_points.items():
    passed_per_group[group] = list(filter(lambda student: students_marks[student] > 60, students_marks.keys()))

print("\n\tTask 5:\n", passed_per_group)

📝 Part 2

Task

Task

1. Create a class CoordinateXY, which represents the coordinate, where X is the first letter of your name, Y is the first letter of your last name.
2. Create a Direction enumeration representing the direction/position (latitude, longitude).
3. Add a Direction property to the CoordinateXY class.
4. Add an Int property and two UInt properties to the CoordinateXY class to represent degrees, minutes, and seconds, respectively.
5. Add initialization methods:
   • with zero default values;
   • with a set of values (degrees, minutes, seconds) (check the input values - degrees ∈ [-90, 90] for latitude ∈ [-180, 180] for longitude, minutes ∈ [0, 59], seconds ∈ [0, 59]).
6. Add methods that return:
   • values of type String in the format “xx°yy′zz″ Z”, where xx - degrees, yy - minutes, zz - seconds, Z - N/S/W/E (depends on Direction);
   • values of type String in the format “xx, xxx...° Z”, where xx, xxx ... - decimal value of the coordinate, Z - N/S/W/E (depends on Direction);
   • an object of type CoordinateXY, which represents the average coordinate between the coordinates represented by the current object and the object obtained as an input parameter, or nil, if the objects have a different direction/position (Direction).
7. Add class methods that return:
   • an object of type CoordinateXY, which represents the average coordinate between the coordinates represented by two objects obtained as input parameters, or nil, if the objects have a different direction/position (Direction).
8. Create multiple CoordinateXY objects using different initializers.
9. Demonstrate the use of the methods from steps 6 and 7 (output the results).

Implementation

Implementation

1. It was decided to expand the task a bit and make it a little more accurate, so the CoordinateJS (JS - Jack Shendrikov) class was designed as a small wrapper of Latitude and Longitude classes. This class contains two initialization options: with 2 parameters (latitude, longitude) or with 3 parameters (latitude, longitude, name).
2. The Latitude class indicates whether the place is located north or south of the equator (or at the equator if latitude 0). The Latitude class also contains the appropriate permissions, such as the maximum allowable latitude value when it is expressed as a floating number, the allowable latitude values are in the range of +/-90.0, and there are rules for allowable values of degrees, minutes, and seconds.
3. The Longitude class indicates whether the location is east or west of the zero meridian (or on the zero meridian if longitude is 0). Also, the Longitude class contains the corresponding permissions, such as the maximum allowable value of longitude, when it is expressed as a floating number, the allowable values of longitude are in the range +/-180.0, there are also rules for allowable values of degrees, minutes and seconds.
4. The abstract class AbsGeoCoordinate is the internal implementation logic for latitude and longitude, also contains the corresponding getters and setters, and a method for verifying the formatted string in degrees-minutes-seconds for the specified locale (eg 48°51'52.97"N for US locale, or 48°51'52,97"N for France locale).
5. The GeoCoordException class is used to handle possible errors.
6. And the last class is DistanceCalculator, which calculates the distance between the coordinates using the Haversin formula, which I chose because of the simplicity of implementation and +/- qualitative accuracy of calculations. The distance can be rotated in kilometers (default value), meters, centimeters or miles. Also in this class there is a method for calculating the average coordinate between 2 points, the method returns a new object CoordinateJS, which can be represented as a string and will look like {xx°yy'zz"Z, xx°yy'zz"Z}.
7. Appropriate unit-tests for main classes (CoordinateJS, Latitude, Longitude and DistanceCalculator) were created to check the work.

Main code for Part 2 is here.

Unit-tests for Part 2 is here.

Version 1.1

📙 About

In this version, we considered the construction of the simplest program for Android with the output of the text about the author. We've also added custom styles to enhance the look, which includes 2 themes: light and dark, which change the slide of the screen left or right.

Custom icons of all sizes have also been created for the application. The app also contains a button that leads to my own portfolio for possible review.

📷 Screenshots