MMKV
React Native 最快的键/值存储。
- MMKV是微信开发的一个高效、小型的移动键值存储框架。更多信息请参见腾讯/MMKV
- react-native-mmkv是一个库，允许您在 React Native 应用程序中轻松使用MMKV。它提供了对原生 C++ 库的快速和直接绑定，可通过简单的 JS API 访问这些库。
安装
yarn add react-native-mmkv
or
npm install react-native-mmkv
手动配置
在 MainApplication.java 中添加 // Add 标记行
import com.reactnativemmkv.MmkvModulePackage; // Add import com.facebook.react.bridge.JSIModulePackage; // Add public class MainApplication extends Application implements ReactApplication { private final ReactNativeHost mReactNativeHost = new ReactNativeHost(this) { @Override public boolean getUseDeveloperSupport() { return BuildConfig.DEBUG; } @Override protected List<ReactPackage> getPackages() { return new PackageList(this).getPackages(); } @Override protected String getJSMainModuleName() { return "index"; } // Add this method here! @Override protected JSIModulePackage getJSIModulePackage() { return new MmkvModulePackage(); } }; // ...
项目中引入
import { MMKV } from 'react-native-mmkv' // --- 以下代码不能在远程 debbuger 模式下运行 --- const storage = new MMKV() storage.set('user.name', 'Marc') storage.set('user.age', 21) const username = storage.getString('user.name') // 'Marc' const age = storage.getNumber('user.age') // 21
运行
安装好 mmkv 后，执行 yarn android 命令启动项目，第一次运行项目构建过程比较慢，需要耐心等待。
如果 yarn android 运行失败
如 react-native-mmkv:downloadxxx FAILED 的错误一般是网络不稳定，下载对应包访问超时导致，可以更换一个更稳定，响应速度更快的站点尝试；
如果对应的包链接 (eg. github.com/react-nativ…) 可以直接在浏览器下载，可以正常下载的情况下，也可以多次执行 yarn android 命令进行重试，有时候也可以成功运行，这种情况有个前提，就是每次报错都是新的包下载异常，而不是已经安装过的或者只有一个包一直下载失败。
重试 yarn android 命令也不能解决问题的情况下，在 android 目录下执行 ./gradlew clean 以及清理 node_modules 目录，重新执行 yarn 和 yarn android 命令；
如果还不行, 删除 /android 和 /android/app 中的 build 文件夹，然后再执行 yarn android
PS D:\code\visitapp-rn> yarn android yarn run v1.22.17 $ react-native run-android info Running jetifier to migrate libraries to AndroidX. You can disable it using "--no-jetifier" flag. Jetifier found 1168 file(s) to forward-jetify. Using 16 workers... info JS server already running. info Installing the app... WARNING:: Please remove usages of `jcenter()` Maven repository from your build scripts and migrate your build to other Maven repositories. This repository is deprecated and it will be shut down in the future. See http://developer.android.com/r/tools/jcenter-end-of-service for more information. Currently detected usages in: project ':react-native-camera', project ':react-native-mmkv', project ':react-native-pager-view', ... > Task :react-native-mmkv:downloadBoost Download https://github.com/react-native-community/boost-for-react-native/releases/download/v1.63.0-0/boost_1_63_0.tar.gz > Task :react-native-mmkv:downloadBoost FAILED 170 actionable tasks: 4 executed, 166 up-to-date FAILURE: Build failed with an exception. * What went wrong: Execution failed for task ':react-native-mmkv:downloadBoost'. > javax.net.ssl.SSLException: Read timed out * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights. * Get more help at https://help.gradle.org BUILD FAILED in 2m 58s error Failed to install the app. Make sure you have the Android development environment set up: https://reactnative.dev/docs/environment-setup. Error: Command failed: gradlew.bat app:installDebug -PreactNativeDevServerPort=8081 FAILURE: Build failed with an exception. * What went wrong: Execution failed for task ':react-native-mmkv:downloadBoost'. > javax.net.ssl.SSLException: Read timed out * Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights. * Get more help at https://help.gradle.org BUILD FAILED in 2m 58s at makeError (D:\code\visitapp-rn\node_modules\execa\index.js:174:9) at D:\code\visitapp-rn\node_modules\execa\index.js:278:16 at processTicksAndRejections (node:internal/process/task_queues:96:5) at async runOnAllDevices (D:\code\visitapp-rn\node_modules\@react-native-community\cli-platform-android\build\commands\runAndroid\runOnAllDevices.js:106:5) at async Command.handleAction (D:\code\visitapp-rn\node_modules\@react-native-community\cli\build\index.js:192:9) info Run CLI with --verbose flag for more details. error Command failed with exit code 1. info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command. 复制代码
注意
mmkv 不能在 react-native-debugger 中运行，会出现如下错误
Failed to create a new MMKV instance, the native initializer function does not exist. Is the native MMKV library correctly installed? Make sure to disable any remote debugger (e.g. Chrome) to use JSI!
