Facilitates implementation of the Presentation Layer, focusing on state management, lifecycle awareness, navigation, and state persistence. Supports hierarchical view composition and messaging between components.
Premo is a Kotlin Multiplatform library that helps to implement the Presentation Layer and share it on Android, iOS, Desktop and Web. Focus on writing logic instead of solving common and boring UI related issues.
Here are some key features:
At the same time, the library does not depend on:
Navigation module implements the following commonly used navigators:
StackNavigator — organizes child presentation models in a stack and navigate between them.The library is based on the ideas of the Presentation Model pattern described by Martin Fowler. The Presentation Model stores the state for presentation and coordinates with the domain model layer.
In practice, you will have not only one Presentation Model, but a composition of child Presentation Models. At the base, there will be a root Presentation Model, from which a tree of children will grow. Children can be pushed into the Stack Navigator, thus organizing the navigation stack.
Such a tree composition is well suited for a hierarchical view as well as for a composition of functions from declarative UI frameworks.
One interesting feature of the tree is that the child keeps a reference to the parent. This allows for messaging between Presentation Models. For example, when some event occurs in a child that requires a reaction from the parent. In this case, the child can send a message towards the root for one of the parents to handle it.
Navigation commands can be the such event. A Child PM sends a message and then its Parent PM can intercept this message and push the next Child PM into the Stack Navigator.
This way of navigation has several advantages:
Add to the root gradle script:
allprojects {
repositories {
mavenCentral()
}
}
Add dependencies to the shared multiplatform module:
kotlin {
sourceSets {
commonMain {
dependencies {
api("me.dmdev.premo:premo:<latest_version>")
api("me.dmdev.premo:premo-navigation:<latest_version>")
api("me.dmdev.premo:premo-saver-json:<latest_version>")
}
}
commonTest {
dependencies {
implementation("me.dmdev.premo:premo-test:<latest_version>")
}
}
}
}
Attention! The library is in the pre-release alpha version. Stable work and backward compatibility are not guaranteed. API may be changed in the future.
Sample demonstrates:
SetNavigatorMasterDetailNavigator — allows to implement an adaptive layout to show one pane or two panes side-by-side.DialogNavigator — helps to show a dialog and wait for the result from itThe MIT License (MIT)
Copyright (c) 2020-2024 Dmitriy Gorbunov (dmitriy.goto@gmail.com)
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