flutter_calculator

Preview

Structure

Input Widgets

input widgets is all extends StatefulWidget, because they need to response the onTap gesture.

• NumberButton. Rendering the number button (like 1,2,3…) and handling the onTap gesture.
• OperatorButton. Rendering the operator button (like +,-,*…) and handling the onTap gesture.
• ResultButton. Rendering the command button (like clear,equal…) and handling the onTap gesture.

Output Widgets

output widgets is all extends StatelessWidget, because they are just rendering.

• ResultDisplay. Rendering the current result and changing display when user tap a number button.
• HistoryBlock. Rendering the calculation histories and changing display every time when user tap a valid button.

CalculatorPage

CalculatorPage is extends StatefulWidget and holding the List of result.

CalculatorPage receives every input widgets onTap event, makes a logical calculation for these input and decide what to display to output widgets.

Credit (github url) : https://github.com/chenyuantao/flutter_calculator

Next Article : https://flutterappdev.com/2019/01/31/flutter-routing-library-that-adds-flexible-routing-options-like-wildcards/