A composable function in Jetpack Compose is a special type of function used to define a UI component that allows you to create reusable pieces of user interface.
Here are some key points about composable functions:
1. Annotation: Composable functions are annotated with @Composable.
@Composable
fun Greeting(name: String) {
Text(text = "Hello, $name!")
}
2. Reactive Updates: Composables are designed to be reactive. This means that if any data they depend on changes, they will automatically update to reflect the new data.
3. State and Parameters: Composables can take parameters, which allow them to customize their behavior. They can also have their own local state.
@Composable
fun Counter() {
var count by remember { mutableStateOf(0) }
Button(onClick = { count++ }) {
Text(text = "Increment")
}
}
when state changes, the remember function ensures that the composable function is reinvoked, and the UI is recomposed to reflect the updated state.
4. Lifecycle-Aware: Compose is aware of the Android lifecycle and manages the UI efficiently, which can lead to improved performance.
5. Preview Functionality: Compose provides a preview system that allows you to see how your composable functions will look in different states directly within your IDE, which is a powerful feature for development.
