16. Creating Custom Widgets

You need to create a simple custom LED indicator widget for a monitoring dashboard that can show different states with colored circles. You begin by subclassing QWidget to create your first custom widget.

You are developing a network monitoring tool and want a custom Signal Strength widget that draws bars of varying heights and colors to represent signal quality. You override paintEvent and use QPainter to create the visual appearance.

In a drawing application, you build a custom ColorPicker widget that responds to mouse clicks and keyboard arrows to let users select and adjust colors interactively.

You have created several custom widgets for a control panel, but they don’t resize properly inside layouts. You implement sizeHint(), minimumSizeHint(), and sizePolicy() so your widgets behave correctly in different layout situations.

You want your custom TemperatureGauge widget to have a value property that can be modified in Qt Designer and emit a valueChanged signal when updated, allowing other parts of the application to react.

You are creating a fitness tracking application and need an attractive Circular Progress widget to show workout completion percentage. You combine painting, mouse interaction, properties, and signals into one complete custom widget.

After building multiple custom widgets, you want to organize them into a reusable library that can be easily imported and used across different projects and even shared with other developers.