Golang, also known as Go, is a popular programming language known for its simplicity, performance, and concurrency support. Fyne is an open-source cross-platform UI toolkit written in Go, which makes it an excellent choice for building desktop applications. In this article, we will discuss how to build a desktop application for stock market data using Golang and Fyne.

Before we dive into the details of building the application, let’s first understand the requirements of the application.

Requirements

  • The application should be able to fetch real-time stock market data from a reliable source.
  • The user should be able to search for a specific stock by its ticker symbol.
  • The application should display the following data for a selected stock:
    • Current price
    • Price change (in percentage and absolute terms)
    • 52-week high and low
    • Market capitalization
    • Volume
    • P/E ratio
  • The application should also display a chart showing the price history of the selected stock.
  • The application should be able to run on Windows, Mac, and Linux.

Fetching Stock Market Data

There are several APIs available that provide real-time stock market data. Some popular ones include Yahoo Finance, Alpha Vantage, and IEX Cloud. In this tutorial, we will use the IEX Cloud API, which provides a wide range of financial data, including stock market data.

To use the IEX Cloud API, you will need to sign up for an account and obtain an API key. The API key is used to authenticate your requests to the API.

Once you have an API key, you can use the following Go libraries to fetch the stock market data:

  • iexcloud-go: A Go client library for the IEX Cloud API.
  • go-iex: A Go wrapper for the IEX Cloud API. Both libraries provide functions to fetch various types of data, including real-time stock quotes, historical prices, and company information.

For example, the following code snippet fetches the real-time quote for a stock with the ticker symbol “AAPL” using the iexcloud-go library:

package main

import (
    "fmt"
    "log"

    "github.com/santegoeds/iexcloud-go"
)

func main() {
    // Set the API key
    iexcloud.SetAPIKey("YOUR_API_KEY")

    // Fetch the real-time quote for the stock "AAPL"
    quote, err := iexcloud.Quote("AAPL")
    if err != nil {
        log.Fatal(err)
    }

    // Print the quote
    fmt.Printf("%+v\n", quote)
}

This will print the real-time quote for the stock “AAPL”, including the current price, price change, and volume.

Building the User Interface

Now that we have the ability to fetch the stock market data, let’s build the user interface for the application using Fyne. Fyne provides a wide range of UI elements, such as buttons, labels, text boxes, and tables, which can be used to build the layout and behavior of the application.

Here is a rough outline of the steps involved in building the user interface:

  1. Create a Go function to initialize the UI elements and layout of the application. This function will create the main window of the application and add the necessary UI elements, such as a search bar, stock data display, and chart.

  2. Use Fyne’s NewContainer function to create a container for the UI elements and specify the layout using Fyne’s layout management functions, such as NewHBox and NewVBox.

  3. Fyne’s NewTextField and NewButton functions to create a search bar and bind the search functionality to the button’s OnTapped event.

  4. Fyne’s NewLabel and NewTable functions to create a table for displaying the stock data. You can bind the data fetched from the IEX Cloud API to the table using Fyne’s SetCell function.

  5. Fyne’s NewCanvas function to create a canvas for rendering the chart. You can use a JavaScript charting library such as Highcharts or D3.js to render the chart on the canvas.

  6. Fyne’s Run function to launch the application and display the main window.

Packaging the Application

Once you have completed the development of the application, you can use the fyne-packager tool to package the application for distribution on Windows, Mac, and Linux. The fyne-packager tool will create a self-contained executable for each platform, which can be easily installed and run on any system.

Conclusion

In this tutorial, we have discussed how to build a desktop application for stock market data using Golang and Fyne. We have seen how to fetch real-time stock market data from the IEX Cloud API and how to build the user interface using Fyne’s UI elements and layout management functions. With these tools and techniques, you can create a powerful and efficient application for tracking and analyzing stock market data.