MMKV for Kotlin Multiplatform

中文版本请参看这里

MMKV-Kotlin is a porting of MMKV to Kotlin Multiplatform. Currently, Android/iOS/macOS are supported.

Tutorial

Installation Via Maven in Gradle

Kotlin Multiplatform Common (kts):

dependencies {     
    implementation("com.ctrip.flight.mmkv:mmkv-kotlin:1.2.15")
}

Current version is based on Kotlin 2.1.0 and MMKV 2.0.0.

Pure Android platform (kts):

dependencies {     
    implementation("com.ctrip.flight.mmkv:mmkv-kotlin-android:1.2.15")
}

Kotlin/Native on macOS：

dependencies { 
    // Intel Chip
    implementation("com.ctrip.flight.mmkv:mmkv-kotlin-macosx64:1.2.15")
    
    // M1&M2 Chip
    implementation("com.ctrip.flight.mmkv:mmkv-kotlin-macosarm64:1.2.15")
}

Note, if your project is a Kotlin/Native executable program project of macOS, or it supplies a framework to an iOS application project directly, then you need to manually add the dependency of MMKV, and may need to add linkerOpts for MMKV and MMKVCore：

kotlin {
    macosX64 {
        binaries {
            // ......
            all {
                val moduleName = "mmkv_operator"
                val mmkvPath = "${buildDir.absolutePath}/cocoapods/synthetic/OSX/$moduleName/build/Release/MMKV"
                val mmkvCorePath = "${buildDir.absolutePath}/cocoapods/synthetic/OSX/$moduleName//build/Release/MMKVCore"
                linkerOpts += listOf(
                    "-F$mmkvPath",
                    "-rpath", mmkvPath,
                    "-framework", "MMKV",
                    "-F$mmkvCorePath",
                    "-rpath", mmkvCorePath,
                    "-framework", "MMKVCore"
                )
            }
        }
    }
    cocoapods {
        // ......
        pod(name = "MMKV") {
            version = "2.0.1"
            moduleName = "MMKV"
        }
    }
    // ......
}

Initialization and Configure Root Path

You can initialize MMKV when your app or the process initialization. MMKV-Android initialization API depends on Context. So, Android's initialization API is different with iOS.

Android:

import com.ctrip.flight.mmkv.initialize

// In Android source set
fun initializeMMKV(context: Context) {
    val rootDir = initialize(context)
    Log.d("MMKV Path", rootDir)
}

iOS:

import com.ctrip.flight.mmkv.initialize

// In iOS source set
fun initializeMMKV(rootDir: String) {
    initialize(rootDir)
    println("MMKV Path: $rootDir")
}

You also could call MMKV-Android (Java) or MMKV-iOS (Objective-C) initialization API in your Android or iOS app project.

CRUD Operations

• MMKV has a global instance, you can use it directly:

import com.ctrip.flight.mmkv.defaultMMKV

fun demo() {
    val kv = defaultMMKV()

    kv.set("Boolean", true)
    println("Boolean: ${kv.takeBoolean("Boolean")}")

    kv.set("Int", Int.MIN_VALUE)
    println("Int: ${kv.takeInt("Int")}")

    kv.set("Long", Long.MAX_VALUE)
    println("Long: ${kv.takeLong("Long")}")

    kv.set("Float", -3.14f)
    println("Float: ${kv.takeFloat("Float")}")

    kv.set("Double", Double.MIN_VALUE)
    println("Double: ${kv.takeDouble("Double")}")

    kv.set("String", "Hello from mmkv")
    println("String: ${kv.takeString("String")}")

    val bytes = byteArrayOf(
        'm'.code.toByte(), 
        'm'.code.toByte(), 
        'k'.code.toByte(), 
        'v'.code.toByte(),
    )
    kv.set("ByteArray", bytes)
    println("ByteArray: ${kv.takeByteArray("ByteArray")?.toString()}")
}

• Deleting & Judging (Whether the key is existed):

kv.removeValueForKey("Boolean")
println("Boolean: ${kv.takeBoolean("Boolean")}")

kv.removeValuesForKeys(listOf("Int", "Long"))
println("allKeys: ${kv.allKeys()}")

val hasBoolean = kv.containsKey("Boolean")

• If a different modules/logics need isolated storage, you can also create your own MMKV instance separately:

import com.ctrip.flight.mmkv.mmkvWithID
...
val kvWithMyId = mmkvWithID("MyID")
kvWithMyId.set("Boolean", true)

• If multi-process accessing is needed, you can set MMKVMode.MULTI_PROCESS when MMKV initialization:

import com.ctrip.flight.mmkv.mmkvWithID
import com.ctrip.flight.mmkv.MMKVModel

...
val kvMultiProcess = mmkvWithID("InterProcessKV", MMKVModel.MULTI_PROCESS)
kvMultiProcess.set("Boolean", true)

Supported Types

• Supported Kotlin types in Kotlin Multiplatform common source set：

  • Boolean, Int, Long, Float, Double, String, UInt, ULong, ByteArray, Set<String>

• The following types are additionally supported in the Android source set:

  • Any class that implements Parcelable

• The following types are additionally supported in the Apple source set:

  • NSDate and any class that implements NSCoding protocol

Note

• MMKV-Kotlin currently does not support migrating old data from SharedPreferences and NSUserDefaults.

License

Distributed under the Apache License, Version 2.0.

See LICENSE for more information.