react-native-mmkv 在 Android 项目中使用
安装
yarn add react-native-mmkv复制代码
or
npm install react-native-mmkv复制代码
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();
}
};
// ...复制代码项目中引入
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复制代码运行
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!
作者：参谋总长萨博
链接：https://juejin.cn/post/7031053837184008228