README-en.md

ComposeWithRedux

a android jetpack compose demo, use redux-kotlin manage app state

By using ksp + kotlinpoet, I implemented this proposal ：Make easy to 'register' reducers

It has a small amount of code and simple functions, but it can help us combine sliceReducer very well

import dependencies：

1. Add the ksp plugin to the build.gradle file in the root directory

  plugins {
      id 'com.google.devtools.ksp' version '1.6.21-1.0.6' apply false
  }

2. Use the ksp plugin in the module and add dependencies

plugins {
  id 'com.google.devtools.ksp'
}
android {
  kotlin {
    sourceSets {
        // Let the IDE recognize the code generated by KSP
        main.kotlin.srcDirs += 'build/generated/ksp'
    }
  }
}
ksp {
  // configure the ksp output directory
  arg("target", "com.example.composewithredux.redux")
}
dependencies {
  implementation project(':compose-redux')
  implementation project(':redux-kotlin-annotation')
  ksp project(':redux-kotlin-processor')
}

Usage：

@SliceReducer("areas")
val areaReducer = reducerForActionType<List<Area>, AreaAction> { state, action ->
    when (action) {
        is AreaAction.AddArea -> {
            state + action.area
        }
        is AreaAction.DelArea -> {
            state.filter {
                it.id != action.id
            }
        }
    }
}

@SliceReducer("name")
fun nameReducer(state: String, action: Any): String? {
    return when (action) {
        is NameAction.Rename -> action.name
        is NameAction.ClearName -> ""
        else -> state
    }
}

We only need to annotate the reducer function with @SliceReducer, and then execute build to automatically generate a complete AppState and rootReducer, the automatically generated files are like this：

// Generated by KSP
package com.example.composewithredux.redux

import kotlin.Any
import kotlin.String
import kotlin.collections.List

public data class AppState(
  public val areas: List<Area>,
  public val name: String,
)

public fun rootReducer(state: AppState, action: Any): AppState = AppState(
   areas = areaReducer(state.areas, action),
   name = nameReducer(state.name, action),
)

In the end, we only need to create a store instance through the createThreadSafeStore function:

val store = createThreadSafeStore(
    ::rootReducer, AppState(
        areas = listOf(
            Area(id = "1", name = "beijing"),
            Area(id = "2", name = "shanghai"),
            Area(id = "3", name = "guangzhou")
        ),
        name = "junerver",
    )
)

This code is unavoidable, because The initial state is required for a ReduxKotlin store, so we need to provide the initial state manually.

Thanks to kotlin's named parameters, even if we add a new sliceReducer function later, we can maintain this initial state through named parameters.