tts = TextToSpeech(context.applicationContext) { status ->
if (status == TextToSpeech.SUCCESS) {
        configure(tts)// 配置
        startSpeaking(messageId, content)// 朗读
    }
}

implementation("androidx.datastore:datastore-preferences:1.2.1")

val Context.dataStore: DataStore<Preferences> by preferencesDataStore(name = "XXX")

object PrefsKeys {
     val DARK_MODE = booleanPreferencesKey("dark_mode")
     val USERNAME = stringPreferencesKey("username")
     val AGE = intPreferencesKey("age") }

val userNameFlow: Flow<String> = context.dataStore.data.map { preferences ->
    preferences[USER_NAME_KEY] ?: "访客"   
}

suspend fun saveUserName( name: String) {
    context.dataStore.edit { settings ->
    settings[PrefsKeys.USERNAME] = name settings
    } 
}

val Context.dataStore by preferencesDataStore(
    name = "new", // DataStore 名字
    produceMigrations = { context ->
        listOf(SharedPreferencesMigration(context,"old"))//旧的 SP 名字
    }  
)

import android.content.Context  
import androidx.datastore.core.DataStore  
import androidx.datastore.preferences.core.Preferences  
import androidx.datastore.preferences.core.edit  
import androidx.datastore.preferences.core.intPreferencesKey  
import androidx.datastore.preferences.core.stringPreferencesKey  
import androidx.datastore.preferences.preferencesDataStore  
import kotlinx.coroutines.flow.Flow  
import kotlinx.coroutines.flow.map  
  
val Context.dataStore: DataStore<Preferences> by preferencesDataStore(name = "user_prefs")  
class DataStoreManager(private val context: Context) {
    //定义 Keys    companion object {
        val USER_NAME_KEY = stringPreferencesKey("user_name")
        val CLICK_COUNT_KEY = intPreferencesKey("click_count")
    }
    //读取数据
    val userNameFlow: Flow<String> = context.dataStore.data.map { preferences ->
        preferences[USER_NAME_KEY] ?: "访客" //默认值为访客
    }
    val clickCountFlow: Flow<Int> = context.dataStore.data.map { preferences ->
        preferences[CLICK_COUNT_KEY] ?: 0
    }
    // 写入数据
    suspend fun saveUserName(name: String) {
        context.dataStore.edit { preferences ->
            preferences[USER_NAME_KEY] = name
        }
    }
    suspend fun incrementClickCount() {
        context.dataStore.edit { preferences ->
            val currentCounterValue = preferences[CLICK_COUNT_KEY] ?: 0
            preferences[CLICK_COUNT_KEY] = currentCounterValue + 1
        }
    }  
}

import android.app.Application  
import androidx.lifecycle.AndroidViewModel  
import androidx.lifecycle.viewModelScope  
import kotlinx.coroutines.launch  
  
class MainViewModel(application: Application) : AndroidViewModel(application) {  

    private val dataStoreManager = DataStoreManager(application)
    val userNameFlow = dataStoreManager.userNameFlow
    val clickCountFlow = dataStoreManager.clickCountFlow
    //保存名字
    fun saveName(name: String) {
        viewModelScope.launch {
            dataStoreManager.saveUserName(name)
        }
    }
    //增加次数
    fun incrementCount() {
        viewModelScope.launch {
            dataStoreManager.incrementClickCount()
        }
    }  
}

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import android.widget.Button
import android.widget.EditText
import android.widget.TextView
import androidx.activity.viewModels
import androidx.lifecycle.Lifecycle
import androidx.lifecycle.lifecycleScope
import androidx.lifecycle.repeatOnLifecycle
import kotlinx.coroutines.launch

class MainActivity : AppCompatActivity() {
    private val viewModel: MainViewModel by viewModels()
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        //都2026了还用findViewById？
        val tvGreeting = findViewById<TextView>(R.id.tvGreeting)
        val tvCounter = findViewById<TextView>(R.id.tvCounter)
        val etName = findViewById<EditText>(R.id.etName)
        val btnSaveName = findViewById<Button>(R.id.btnSaveName)
        val btnIncrement = findViewById<Button>(R.id.btnIncrement)  

        btnSaveName.setOnClickListener {
            val name = etName.text.toString()
            if (name.isNotBlank()) {
                viewModel.saveName(name)
                etName.text.clear()
            }
        }  

        btnIncrement.setOnClickListener {
            viewModel.incrementCount()
        }  

        //监听DataStore数据的变化，自动更新 UI
        lifecycleScope.launch {
    //节省资源罢了
            repeatOnLifecycle(Lifecycle.State.STARTED) {
        // 监听名字变化
            launch {
            viewModel.userNameFlow.collect { name ->
                tvGreeting.text = "你好，$name！"  
            }  
        }        //监听点击次数变化  
            launch {  
                viewModel.clickCountFlow.collect { count ->  
                tvCounter.text = "点击次数: $count"
            }
                }
            }
        }
    }  
}