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JetPack datastore的优势以及使用方法_datastore 优点

作者：知新_RL | 2024-03-25 11:19:22

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datastore 优点

谷歌自2020年开始推出datastore旨在替代原有SharedPreferences，解决SharedPreferences的不足

一、DataStore 相比于 SharedPreferences 优点

1. DataStore 是基于 Flow 实现的，所以保证了在主线程的安全性。

2. 以事务方式处理更新数据，事务有四大特性（原子性、一致性、 隔离性、持久性）。

3. 可以监听到操作成功或者失败结果。

5. SharedPreferences第一次加载数据时需要全量加载，当数据量大时可能会阻塞UI线程造成卡顿

6.SharedPreferencesh在执行commit() / apply()操作可能会造成ANR问题

7.相对于SharedPreferences体积更小

二、datastroe使用教程：

1.引用datastore-preferences、datastore-preferences-core库

  1. object Datastore {
  2.     val preferences = "androidx.datastore:datastore-preferences:${DependencyVersionManager.datastore}"
  3.     val preferences_core = "androidx.datastore:datastore-preferences-core:${DependencyVersionManager.datastore}"
  4. }

2.根据项目中SharedPreferences保存路径替换成datastore路径

通过SharedPreferencesMigration迁移类，只要从工具类中执行了独写操作，都会从SharedPreferences路径中copy一份至datastore路径下，然后自动删除原文件

  1. private val Context.dataStore by preferencesDataStore(
  2.         name = Constants.Prefs.DATA_STORE_NAME,//datastore 路径
  3.         produceMigrations = { context ->
  4.             listOf(SharedPreferencesMigration(context, Constants.Prefs.PREFRENCE_NAME))//SharedPreferences 路径
  5.         }
  6. )

3.根据不同的数据类型对datastore进行封装

  1. object EasyDataStore {
  2.  
  3.     /**
  4.      * 存数据
  5.      */
  6.     @Suppress("UNCHECKED_CAST")
  7.     fun <T> putData(context: Context, key: String, value: T) {
  8.         runBlocking {
  9.             when (value) {
  10.                 is Int -> putIntData(context, key, value)
  11.                 is Long -> putLongData(context, key, value)
  12.                 is String -> putStringData(context, key, value)
  13.                 is Boolean -> putBooleanData(context, key, value)
  14.                 is Float -> putFloatData(context, key, value)
  15.                 is Double -> putDoubleData(context, key, value)
  16.                 else -> throw IllegalArgumentException("This type cannot be saved to the Data Store")
  17.             }
  18.         }
  19.     }
  20.  
  21.     /**
  22.      * 取数据
  23.      */
  24.     @Suppress("UNCHECKED_CAST")
  25.     fun <T> getData(context: Context, key: String, defaultValue: T): T {
  26.         val data = when (defaultValue) {
  27.             is Int -> getIntData(context, key, defaultValue)
  28.             is Long -> getLongData(context, key, defaultValue)
  29.             is String -> getStringData(context, key, defaultValue)
  30.             is Boolean -> getBooleanData(context, key, defaultValue)
  31.             is Float -> getFloatData(context, key, defaultValue)
  32.             is Double -> getDoubleData(context, key, defaultValue)
  33.             else -> throw IllegalArgumentException("This type cannot be saved to the Data Store")
  34.         }
  35.         return data as T
  36.     }
  37.  
  38.     /**
  39.      * 清空数据
  40.      */
  41.     fun clearData(context: Context) = runBlocking { context.dataStore.edit { it.clear() } }
  42.  
  43.  
  44.     /**
  45.      * 存放Int数据
  46.      */
  47.     private suspend fun putIntData(context: Context, key: String, value: Int) = context.dataStore.edit {
  48.         it[intPreferencesKey(key)] = value
  49.     }
  50.  
  51.     /**
  52.      * 存放Long数据
  53.      */
  54.     private suspend fun putLongData(context: Context, key: String, value: Long) = context.dataStore.edit {
  55.         it[longPreferencesKey(key)] = value
  56.     }
  57.  
  58.     /**
  59.      * 存放String数据
  60.      */
  61.     private suspend fun putStringData(context: Context, key: String, value: String) = context.dataStore.edit {
  62.         it[stringPreferencesKey(key)] = value
  63.     }
  64.  
  65.     /**
  66.      * 存放Boolean数据
  67.      */
  68.     private suspend fun putBooleanData(context: Context, key: String, value: Boolean) = context.dataStore.edit {
  69.         it[booleanPreferencesKey(key)] = value
  70.     }
  71.  
  72.     /**
  73.      * 存放Float数据
  74.      */
  75.     private suspend fun putFloatData(context: Context, key: String, value: Float) = context.dataStore.edit {
  76.         it[floatPreferencesKey(key)] = value
  77.     }
  78.  
  79.     /**
  80.      * 存放Double数据
  81.      */
  82.     private suspend fun putDoubleData(context: Context, key: String, value: Double) = context.dataStore.edit {
  83.         it[doublePreferencesKey(key)] = value
  84.     }
  85.  
  86.     /**
  87.      * 取出Int数据
  88.      */
  89.     private fun getIntData(context: Context, key: String, default: Int = 0): Int = runBlocking {
  90.         return@runBlocking context.dataStore.data.map {
  91.             it[intPreferencesKey(key)] ?: default
  92.         }.first()
  93.  
  94.     }
  95.  
  96.     /**
  97.      * 取出Long数据
  98.      */
  99.     private fun getLongData(context: Context, key: String, default: Long = 0): Long = runBlocking {
  100.         return@runBlocking context.dataStore.data.map {
  101.             it[longPreferencesKey(key)] ?: default
  102.         }.first()
  103.     }
  104.  
  105.     /**
  106.      * 取出String数据
  107.      */
  108.     private fun getStringData(context: Context, key: String, default: String? = null): String = runBlocking {
  109.         return@runBlocking context.dataStore.data.map {
  110.             it[stringPreferencesKey(key)] ?: default
  111.         }.first()!!
  112.     }
  113.  
  114.     /**
  115.      * 取出Boolean数据
  116.      */
  117.     private fun getBooleanData(context: Context, key: String, default: Boolean = false): Boolean = runBlocking {
  118.         return@runBlocking context.dataStore.data.map {
  119.             it[booleanPreferencesKey(key)] ?: default
  120.         }.first()
  121.     }
  122.  
  123.     /**
  124.      * 取出Float数据
  125.      */
  126.     private fun getFloatData(context: Context, key: String, default: Float = 0.0f): Float = runBlocking {
  127.         return@runBlocking context.dataStore.data.map {
  128.             it[floatPreferencesKey(key)] ?: default
  129.         }.first()
  130.     }
  131.  
  132.     /**
  133.      * 取出Double数据
  134.      */
  135.     private fun getDoubleData(context: Context, key: String, default: Double = 0.00): Double = runBlocking {
  136.         return@runBlocking context.dataStore.data.map {
  137.             it[doublePreferencesKey(key)] ?: default
  138.         }.first()
  139.     }
  140.  
  141. }

4.在需要对数据进行读写的地方分别调用getData和putData

5.完整Datastore工具类代码见下：

  1. package com.ovopark.utils
  2.  
  3. import android.content.Context
  4. import androidx.datastore.preferences.SharedPreferencesMigration
  5. import androidx.datastore.preferences.core.*
  6. import androidx.datastore.preferences.preferencesDataStore
  7. import com.ovopark.common.Constants
  8. import kotlinx.coroutines.flow.first
  9. import kotlinx.coroutines.flow.map
  10. import kotlinx.coroutines.runBlocking
  11.  
  12.  
  13. /**
  14.  * 创建人：yaoao
  15.  * 创建日期：2022/6/28.9:37
  16.  * 描述：DataStore封装工具类
  17.  * 修改人：
  18.  * 迭代版本：
  19.  * 迭代说明：
  20.  */
  21. private val Context.dataStore by preferencesDataStore(
  22.         name = Constants.Prefs.DATA_STORE_NAME,
  23.         produceMigrations = { context ->
  24.             // Since we're migrating from SharedPreferences, add a migration based on the
  25.             // SharedPreferences name
  26.             listOf(SharedPreferencesMigration(context, Constants.Prefs.PREFRENCE_NAME))
  27.         }
  28. )
  30. object EasyDataStore {
  32.     /**
  33.      * 存数据
  34.      */
  35.     @Suppress("UNCHECKED_CAST")
  36.     fun <T> putData(context: Context, key: String, value: T) {
  37.         runBlocking {
  38.             when (value) {
  39.                 is Int -> putIntData(context, key, value)
  40.                 is Long -> putLongData(context, key, value)
  41.                 is String -> putStringData(context, key, value)
  42.                 is Boolean -> putBooleanData(context, key, value)
  43.                 is Float -> putFloatData(context, key, value)
  44.                 is Double -> putDoubleData(context, key, value)
  45.                 else -> throw IllegalArgumentException("This type cannot be saved to the Data Store")
  46.             }
  47.         }
  48.     }
  50.     /**
  51.      * 取数据
  52.      */
  53.     @Suppress("UNCHECKED_CAST")
  54.     fun <T> getData(context: Context, key: String, defaultValue: T): T {
  55.         val data = when (defaultValue) {
  56.             is Int -> getIntData(context, key, defaultValue)
  57.             is Long -> getLongData(context, key, defaultValue)
  58.             is String -> getStringData(context, key, defaultValue)
  59.             is Boolean -> getBooleanData(context, key, defaultValue)
  60.             is Float -> getFloatData(context, key, defaultValue)
  61.             is Double -> getDoubleData(context, key, defaultValue)
  62.             else -> throw IllegalArgumentException("This type cannot be saved to the Data Store")
  63.         }
  64.         return data as T
  65.     }
  67.     /**
  68.      * 清空数据
  69.      */
  70.     fun clearData(context: Context) = runBlocking { context.dataStore.edit { it.clear() } }
  73.     /**
  74.      * 存放Int数据
  75.      */
  76.     private suspend fun putIntData(context: Context, key: String, value: Int) = context.dataStore.edit {
  77.         it[intPreferencesKey(key)] = value
  78.     }
  80.     /**
  81.      * 存放Long数据
  82.      */
  83.     private suspend fun putLongData(context: Context, key: String, value: Long) = context.dataStore.edit {
  84.         it[longPreferencesKey(key)] = value
  85.     }
  87.     /**
  88.      * 存放String数据
  89.      */
  90.     private suspend fun putStringData(context: Context, key: String, value: String) = context.dataStore.edit {
  91.         it[stringPreferencesKey(key)] = value
  92.     }
  94.     /**
  95.      * 存放Boolean数据
  96.      */
  97.     private suspend fun putBooleanData(context: Context, key: String, value: Boolean) = context.dataStore.edit {
  98.         it[booleanPreferencesKey(key)] = value
  99.     }
  101.     /**
  102.      * 存放Float数据
  103.      */
  104.     private suspend fun putFloatData(context: Context, key: String, value: Float) = context.dataStore.edit {
  105.         it[floatPreferencesKey(key)] = value
  106.     }
  108.     /**
  109.      * 存放Double数据
  110.      */
  111.     private suspend fun putDoubleData(context: Context, key: String, value: Double) = context.dataStore.edit {
  112.         it[doublePreferencesKey(key)] = value
  113.     }
  115.     /**
  116.      * 取出Int数据
  117.      */
  118.     private fun getIntData(context: Context, key: String, default: Int = 0): Int = runBlocking {
  119.         return@runBlocking context.dataStore.data.map {
  120.             it[intPreferencesKey(key)] ?: default
  121.         }.first()
  123.     }
  125.     /**
  126.      * 取出Long数据
  127.      */
  128.     private fun getLongData(context: Context, key: String, default: Long = 0): Long = runBlocking {
  129.         return@runBlocking context.dataStore.data.map {
  130.             it[longPreferencesKey(key)] ?: default
  131.         }.first()
  132.     }
  134.     /**
  135.      * 取出String数据
  136.      */
  137.     private fun getStringData(context: Context, key: String, default: String? = null): String = runBlocking {
  138.         return@runBlocking context.dataStore.data.map {
  139.             it[stringPreferencesKey(key)] ?: default
  140.         }.first()!!
  141.     }
  143.     /**
  144.      * 取出Boolean数据
  145.      */
  146.     private fun getBooleanData(context: Context, key: String, default: Boolean = false): Boolean = runBlocking {
  147.         return@runBlocking context.dataStore.data.map {
  148.             it[booleanPreferencesKey(key)] ?: default
  149.         }.first()
  150.     }
  152.     /**
  153.      * 取出Float数据
  154.      */
  155.     private fun getFloatData(context: Context, key: String, default: Float = 0.0f): Float = runBlocking {
  156.         return@runBlocking context.dataStore.data.map {
  157.             it[floatPreferencesKey(key)] ?: default
  158.         }.first()
  159.     }
  161.     /**
  162.      * 取出Double数据
  163.      */
  164.     private fun getDoubleData(context: Context, key: String, default: Double = 0.00): Double = runBlocking {
  165.         return@runBlocking context.dataStore.data.map {
  166.             it[doublePreferencesKey(key)] ?: default
  167.         }.first()
  168.     }
  170. }

注意： SharedPreferences有remove方法可以单独对一些键进行删除操作，但是对datastore查找源码并没有此类方法，只能对键进行置空操作

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