Gradle(Project)

dependencies {
    classpath 'com.google.protobuf:protobuf-gradle-plugin:0.8.13'
Gradle(Module)
apply plugin: 'com.google.protobuf'
dependencies {
    implementation  "androidx.datastore:datastore-core:1.0.0-alpha01"
    implementation  "com.google.protobuf:protobuf-javalite:3.10.0"
    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.9'
protobuf {
    protoc {
        artifact = "com.google.protobuf:protoc:3.10.0"
    generateProtoTasks {
        all().each { task ->
            task.builtins {
                java {
                    option 'lite'
在app/src/main/proto新增user_prefs.proto

設定完後先編譯
syntax = "proto3";
option java_package = "com.example.app_datastore";
option java_multiple_files = true;
message UserPreferences {
    string account = 1;
    string password = 2;
    bool remember = 3;
繼承Serializer 並把剛剛的UserPreferences導入
object UserPreferencesSerializer : Serializer<UserPreferences> {
    override fun readFrom(input: InputStream): UserPreferences {
        try {
            return UserPreferences.parseFrom(input)
        } catch (exception: InvalidProtocolBufferException) {
            throw CorruptionException("Cannot read proto.", exception)
    override fun writeTo(t: UserPreferences, output: OutputStream) = t.writeTo(output)
創建Model
data class User(var account: String?, var password: String?, var remember: Boolean)
MainActivity
class MainActivity : AppCompatActivity() {
    //創建DataStore 
    private val dataStore by lazy {
        applicationContext.createDataStore(
            fileName = "user_prefs.pb",
            serializer = UserPreferencesSerializer
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        //讀取數據 塞入Model
        CoroutineScope(Dispatchers.IO).launch {
            val user = dataStore.data.map { user ->
                User(user.account, user.password, user.remember)
            withContext(Dispatchers.Main) {
                user.collect { user ->
                    account.setText(user.account)
                    password.setText(user.password)
                    remember.isChecked = user.remember
    //寫入數據
    private suspend fun putData(account: String, password: String, remember: Boolean) {
        dataStore.updateData { preferences ->
            preferences.toBuilder().setAccount(account)
                .setPassword(password)
                .setRemember(remember)
                .build()
    fun save(view: View) {
        CoroutineScope(Dispatchers.IO).launch {
            val account = account.text.toString()
            val password = password.text.toString()
            val remember = remember.isChecked
            putData(account, password, remember)