John discovered that with SwiftUI, crafting intuitive user interfaces becomes a breeze. One day, he decided to experiment and make a basic calculator. For the sake of simplicity, he designed it to add or subtract whole numbers.


Before John began, he ensured that he had both Xcode 11 and MacOS Catalina. He knew that these could be fetched from Apple’s developer portal.

Setting up the Project:

  1. John initiated Xcode. On the startup window, he chose to “Create a new Xcode project”. Alternatively, he could’ve gone through File > New > Project;
  2. In the template section, he chose ‘iOS’ for the platform and ‘Single View App’ for the template before proceeding;
  3. Naming the product “SwiftUICalculatorTutorial”, he made sure SwiftUI was selected as the User Interface. After deciding on a storage location for his project, he pressed ‘Next’.

Configuring the Canvas:

John activated the canvas by clicking ‘Resume’ to view the preview. If for some reason he couldn’t see the canvas, he knew that selecting Editor > Editor and Canvas would make it visible.

Structuring the ContentView:

Inside ContentView.swift, John declared several variables:

  • `firstNumber` and `secondNumber`: Represented the numbers involved in the calculation;
  • `operand`: Identified the operation, which could be either addition or subtraction;
  • `calculatorText`: Displayed the current value;
  • `isTypingNumber`: A boolean to ascertain if a multi-digit number was being entered.

Designing the Calculator’s UI:

John then embarked on developing the calculator’s appearance. He displayed numbers using the `createCalcDigit(_:)` method and integrated functionality where tapping an operand would trigger the `operandTapped(_:)` method. Moreover, tapping the equal sign called upon the `calculate()` method to finalize the computation.

Incorporating Functionality:

For the calculator to function, John introduced several methods:

  1. `createCalcDigit(_:)`: This displayed each calculator button;
  2. `digitTapped(_:)`: It determined if a new number was being added and updated the calculator’s display accordingly;
  3. `operandTapped(_:)`: Here, the displayed number shifted to the `firstNumber` variable and displayed the chosen operand;
  4. `calculate()`: This function computed the values based on the chosen operand.

Testing the Calculator

After all this setup, John was eager to test his creation. He moved to the preview canvas and initiated the Live Preview feature. He punched in a few numbers, performed a calculation, and was delighted to see it worked flawlessly.

John’s journey with SwiftUI had just begun, but he was already enamored by its capabilities. The realm of UI development had previously seemed dense and intricate, but SwiftUI was like a breath of fresh air. The clarity and simplicity it offered were unparalleled. It wasn’t just the convenience that SwiftUI offered, but the community around it was supportive too. Forums and online groups were buzzing with enthusiasts sharing their SwiftUI projects, offering solutions, and celebrating each other’s accomplishments. This not only amplified John’s motivation but also ensured that he always had someone to turn to if he ever hit a roadblock.

One evening, as he reminisced about the initial days of his programming journey, John remembered the trepidation he felt when writing his first line of code. Now, with tools like SwiftUI, he felt empowered. The barriers to entry in the app development world seemed to be lowering, and John was optimistic about the future. He envisioned a world where even those without a deep technical background could bring their ideas to life with a few lines of code. Every project, like this calculator, was a stepping stone for him. With each endeavor, he unraveled more layers of SwiftUI and uncovered new tricks and methodologies. He started maintaining a journal, documenting his experiences, challenges faced, and solutions discovered. John believed that his notes would someday assist another budding developer.

To wrap up

He often thought about the expansive world of app development. The calculator was just a basic project, but the horizon was vast. From utility apps to intricate games, the possibilities seemed endless. John was enthusiastic about diving deeper into SwiftUI, exploring more complex projects, and contributing to the community that had provided him with so much support. He cherished the thought of how simple lines of code could culminate into impactful applications, making daily tasks more manageable, or even just bringing a smile to someone’s face. The power of app development was profound, and John was just getting started.

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