第一个react native的运行

以下用的是react native cli的方式。如果使用Expo Go，请参考：https://reactnative.dev/docs/environment-setup?guide=quickstart

1. 安装cli命令：

   npm uninstall -g react-native-cli
   npm uninstall -g create-react-app
   npm install -g react-native

2. 尝试运行：

   react-native init myFirstProject

   结果报错误1 ， 就升级ruby to 3（通过安装rvm），安装cocoapods

3. 再次运行 react-native init myFirstProject ，依然报错，见错误2 ， 安装watchman

4. 卸载了global安装的react-native-cli ，使用npx react-native@latest init AwesomeProject来新建项目。

   If you previously installed a global react-native-cli package, please remove it as it may cause unexpected issues:

npm uninstall -g react-native-cli @react-native-community/cli

5. 这时还有错误2， 于是我又在xcode中设置了xcode command tools，和 IOS Simulator，又确保xcode command tools设置正确了。再次运行：

    npx react-native@latest init AwesomeProject

   这时才成功了。

    可以用 npx react-native info 来看看当前最新的react native的版本信息

6. 创建项目并build成功后。
    npx react-native start     // starts Metro Bundler (也可以不执行, 但执行了后启动Metro)
    npx react-native run-ios     // go to your project folder

 

运行的时候也可以用XCode打开项目下的ios文件夹，打开 app..xcodeproj 或 app..xcworkspace , 然后运行模拟器

----------------------------------------------- 遇到的错误列表 --------------------------------------

错误1:

mac上运行命令：react-native init myFirstProject --verbose   。 提示需要安装CocoaPods，

运行：sudo gem install cocoapods        报错如下：

ERROR: Error installing cocoapods:
The last version of activesupport (>= 5.0, < 8) to support your Ruby & RubyGems was 6.1.7.3. Try installing it with `gem install activesupport -v 6.1.7.3` and then running the current command again
activesupport requires Ruby version >= 2.7.0. The current ruby version is 2.6.10.210.

我选择了升级ruby到2.7，于是根据chatgpt的提示，我又参考了：https://stackoverflow.com/questions/60182199/upgrading-global-ruby-version-on-macos 和 https://rvm.io/rvm/install ， 安装了rvm，然后安装2.7 ruby

gpg --keyserver keyserver.ubuntu.com --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 7D2BAF1CF37B13E2069D6956105BD0E739499BDB

\curl -sSL https://get.rvm.io | bash -s stable --ruby

---- 安装完rvm后本来还要安装ruby 3，需要执行以下命令的：，结果发现ruby 3自动被安装了，可以通过rvm list查看，所以不用执行rvm install 3.2了。

rvm install (ruby version)

rvm --default use (ruby version)

can use rvm list to see available ruby versions.

# 安装 cocoapods

sudo gem install cocoapods

最后执行：react-native init myFirstProject --verbose ，还是错误，让我去到这里配置ios环境：https://reactnative.dev/docs/next/environment-setup

 ---- 错误2:

✖ Installing CocoaPods dependencies (this may take a few minutes)
error Error: Looks like your iOS environment is not properly set. Please go to https://reactnative.dev/docs/next/environment-setup and follow the React Native CLI QuickStart guide for macOS and iOS.
Error: Error: Looks like your iOS environment is not properly set. Please go to https://reactnative.dev/docs/next/environment-setup and follow the React Native CLI QuickStart guide for macOS and iOS.

于是参考 https://reactnative.dev/docs/next/environment-setup 中的“React Native CLI Quickstart”部分，执行：brew install watchman ，然后在XCode上执行一些操作：
1）安装Command Line Tools ： xcode.setting -> Locations , 找到 “Command Line Tools”，选择版本，点下上下箭头确保设置好了。

2）Installing an iOS Simulator in Xcode：To install a simulator, open Xcode > Settings... (or Preferences...) and select the Platforms (or Components) tab. Select a simulator with the corresponding version of iOS you wish to use.

参考：
https://hackmd.io/@sandyuu/B1FP7VL1F

---- 错误3: 

有时候有这个错误：React Native Error: No bundle URL present ， 和这个错误：cannot read property handleSetJSResponder of null 

参考：https://www.kindacode.com/article/react-native-no-bundle-url-present/#:~:text=When%20developing%20an%20iOS%20app%20with%20React%20Native%2C,have%20included%20a.jsbundle%20file%20in%20your%20application%20bundle.

我的解决方式是：a) cd ios  b) pod install  c) npm start  d) 在app上点击R，重新load app后结局。

---- 错误4: 

当运行expo start时，有时报这个错误：

opensslErrorStack: [ 'error:03000086:digital envelope routines::initialization error' ],
  library: 'digital envelope routines',
  reason: 'unsupported',
  code: 'ERR_OSSL_EVP_UNSUPPORTED'

临时解决办法：export NODE_OPTIONS=--openssl-legacy-provider

---- 错误5: 

执行expo start的时候，报这个错误：

Error running `xcrun simctl install 8CEB33A4-0A3D-444F-9C91-E4B428C2C529 /Users/peterfan/.expo/ios-simulator-app-cache/Exponent-2.23.2.tar.app`: An error was encountered processing the command (domain=NSPOSIXErrorDomain, code=22):
Simulator device returned an error for the requested operation.
The application's Info.plist does not contain a valid CFBundleVersion.
Ensure your bundle contains a valid CFBundleVersion.

参考： https://github.com/expo/expo-cli/issues/2413    and    https://stackoverflow.com/questions/51147704/expo-error-installing-or-running-app

但是对于我的测试来说，是因为：我terminal开启了代理proxy，导致下载expo tar包时有问题，没法部署到iphone simulator上的错误。