Base Widget (lv_obj)

The most fundamental of all widgets is the Base Widget, on which all other widgets are based. From an object-oriented perspective, think of the Base Widget as the widget class from which all other widgets inherit.

By this mechanism, all widgets carry the features of the Base Widget. Therefore, the functions and functionalities of the Base Widget can be used with other widgets as well. For example: lv_obj_set_width(slider, 100).

Although it's just a simple rectangle, the Base Widget is the most powerful widget, as it supports all the features that other widgets can use.

The Base Widget can have:

• Children

• Position and Size

• Layouts

• Styles

• Events

• Data bindings

• Flags

• Parts and States

• And many more

A Slider widget, for example, uses these features to realize slider-like behavior, but it’s all based on the same style, event, layout, and other concepts supported by the Base Widget.

All these common and versatile features are introduced in the Common Widget Features chapter.

In HTML terms, think of it as a <div>, a very versatile building block that, with some CSS and JS, can become almost anything.