Attempt fix #401

compose-persist/.gitignore

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+/build

compose-persist/build.gradle.kts

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+plugins {
+    id("com.android.library")
+    kotlin("android")
+}
+
+android {
+    namespace = "it.vfsfitvnm.compose.persist"
+    compileSdk = 33
+
+    defaultConfig {
+        minSdk = 21
+        targetSdk = 33
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = true
+            proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"))
+        }
+    }
+
+    sourceSets.all {
+        kotlin.srcDir("src/$name/kotlin")
+    }
+
+    buildFeatures {
+        compose = true
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
+    }
+
+    composeOptions {
+        kotlinCompilerExtensionVersion = libs.versions.compose.compiler.get()
+    }
+
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}
+
+dependencies {
+    implementation(libs.compose.foundation)
+}

compose-persist/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest>
+
+</manifest>

compose-persist/src/main/kotlin/it/vfsfitvnm/compose/persist/Persist.kt

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+package it.vfsfitvnm.compose.persist
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.MutableState
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.ui.platform.LocalContext
+
+@Suppress("UNCHECKED_CAST")
+@Composable
+fun <T> persist(tag: String, initialValue: T): MutableState<T> {
+    val context = LocalContext.current
+
+    return remember {
+        context.persistMap?.getOrPut(tag) { mutableStateOf(initialValue) } as? MutableState<T>
+            ?: mutableStateOf(initialValue)
+    }
+}
+
+@Composable
+fun <T> persistList(tag: String): MutableState<List<T>> =
+    persist(tag = tag, initialValue = emptyList())
+
+@Composable
+fun <T : Any?> persist(tag: String): MutableState<T?> =
+    persist(tag = tag, initialValue = null)

compose-persist/src/main/kotlin/it/vfsfitvnm/compose/persist/PersistMap.kt

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+package it.vfsfitvnm.compose.persist
+
+typealias PersistMap = HashMap<String, Any?>

compose-persist/src/main/kotlin/it/vfsfitvnm/compose/persist/PersistMapCleanup.kt

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+package it.vfsfitvnm.compose.persist
+
+import android.app.Activity
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.DisposableEffect
+import androidx.compose.ui.platform.LocalContext
+
+@Composable
+fun PersistMapCleanup(tagPrefix: String) {
+    val context = LocalContext.current
+
+    DisposableEffect(context) {
+        onDispose {
+            if (context.findOwner<Activity>()?.isChangingConfigurations == false) {
+                context.persistMap?.keys?.removeAll { it.startsWith(tagPrefix) }
+            }
+        }
+    }
+}

compose-persist/src/main/kotlin/it/vfsfitvnm/compose/persist/PersistMapOwner.kt

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+package it.vfsfitvnm.compose.persist
+
+interface PersistMapOwner {
+    val persistMap: PersistMap
+}

compose-persist/src/main/kotlin/it/vfsfitvnm/compose/persist/Utils.kt

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+package it.vfsfitvnm.compose.persist
+
+import android.content.Context
+import android.content.ContextWrapper
+
+val Context.persistMap: PersistMap?
+    get() = findOwner<PersistMapOwner>()?.persistMap
+
+internal inline fun <reified T> Context.findOwner(): T? {
+    var context = this
+    while (context is ContextWrapper) {
+        if (context is T) return context
+        context = context.baseContext
+    }
+    return null
+}