Moving from components to composable functions

So far, I explained the word component by saying that it refers to UI elements. In fact, the term is used in quite a few other areas. Generally speaking, components structure systems by separating distinct portions or parts of them. The inner workings of a component are typically hidden from the outside (known as the black box principle).

Tip

To learn more about the black box principle, please refer to https://en.wikipedia.org/wiki/Black_box.

Components communicate with other parts of the system by sending and receiving messages. The appearance or behavior of a component is controlled through a set of attributes, or properties.

Consider TextView. We set text by modifying the text property and we control its visibility through visibility. What about sending and receiving messages? Let’s look at Button. We can react to clicks (receive a message) by registering (sending a message) an OnClickListener instance. The same principle...