Lab assignment #$9$

Topics: Python GUI

Problem Statement:

This assignment is a continuation of last LA and it$$s a small part of the final project. The purpose

of this lab assignment is to gain experience in python$$s tkinter GUI Application. In this assignment,

we will design a simple small appsstore. The details are provided in the template file. Write down

the code where it says $$###your code here$.$

Design Solution:

The assignment is composed of two different files: CLASS and GUI file. In this assignment we

will learn about the connection between a GUI interface to the back$-$end $($class definition$)$ of the

program.

$1.$ CLASS file contains a simple Apps Item class definition to describe an application. Each

product information is composed of: category$/$genre$,$ name, price, ratings and product

ID$.$ The information will be read from a given sample input file $($this file is different from

the project file but follow same format$).$ The file looks as follows:

ID$,$name,price,rating,category it $($Note the order of information$)$

You need to read the information from the file and store it in a category dictionary. This

dictionary will be a class variable in the Item class. The key will be a category name and

the values will be list of Item objects. Details provided in the CLASS file. Once the

information is read, an Apps Item object will be created and added to dictionary per

category. You need to complete the Item class definition. You can test the CLASS file

separately by printing the information in the category dictionary. A testing code is

provided at the end of the class file.

$2.$ GUI file is composed of most of the graphical component information. The GUI looks

very similar to the previous LA$.$ Major differences from previous one are listed below:

a$.$ GUI file will import CLASS file$$s Apps Item class and this way will have access to

category dictionary.

b$.$ Shop$\_$by$\_$apps$\_$category$()$ is a new method added. This allows the user to

choose apps by category. For this assignment there are two categories only:

games and weather. Selecting a particular category will call start method with a

parameter: Item.category$\_$dict$[$category$],$ which is essentially a list of apps

object for that particular category. More implementation details are given.

Sample Output:

$1.$ First window: Start ordering will start the program. This will be a button, pressing the

button will start the code and take user to the second window

$2.$ Second Window: Second window will display the following category window, each of

the category name shown is actually a button, clicking on the button will take to the list

of apps for that category.

$3.$ Third Window: User will be displayed with all the apps available for that category. For

this assignment, apps information is obtained from a file and stored in a dictionary. This

dictionary will be imported from CLASS to GUI file. The information to be displayed to

the users are: name $($checkbutton$**),$ price $($label$),$ ID$($label$),$ rating$($label$)$ and

category$/$genre $($label$)$ as follows:

This window also contains subtotal label, select by categories label to select a different

category and an $$Add to Cart$$ button.

$**$ Check button: are interactive buttons to select$/$unselect an item. When user presses the

check button that means the item is being selected. Following is a sample code to create a

check button.

How to create a checkbutton:

var $=$ IntVar$()$ #associate an IntVar$()$ with $0/1.$

c $=$ Checkbutton$($root$,$ text$=$"egg", variable$=$var$)$ #obtain the name from the Item class method

c$.$pack$()$

By default, the variable is set to $1$ if the button is selected, and $0$ otherwise. variable$=$Associates

a Tkinter variable to the check button. When the check button is pressed, the variable is toggled

between $0$ and $1.$ Method get$()$ returns the current selection value.

$4.$ Item selected and add to cart: Two apps Item selected and subtotal shown below. After

selection, pressing $$Add to Cart$$ button will display the subtotal label at the left.

$5.$ User can press select by categories button to select another category and perform

similar operation as in #$4.$

Submission:

$1.$ All submission will be via BlackBoard as directed.

$2.$ Helpful resources: lab instructor, lecture videos, slides and codes, python documentation

$3.$ The codes need to be written in the firstname$\_$lastname$\_$LA$9\_$CLASS.py and

firstname$\_$lastname$\_$LA$9\_$GUI.py files.