iOS
- CDN: trunk URL couldn't be downloaded
pod install
Analyzing dependencies
Fetching podspec for `DoubleConversion` from `../node_modules/react-native/third-party-podspecs/DoubleConversion.podspec`
Fetching podspec for `Folly` from `../node_modules/react-native/third-party-podspecs/Folly.podspec`
Fetching podspec for `glog` from `../node_modules/react-native/third-party-podspecs/glog.podspec`
[!] CDN: trunk Repo update failed - 44 error(s):
CDN: trunk URL couldn't be downloaded: https://cdn.cocoapods.org/Specs/3/2/5/FlipperKit/0.11.1/FlipperKit.podspec.json, error: Net::OpenTimeout
...
A：
https://www.jianshu.com/p/6f53147e4409
Podfile中(首行)显示指定源
source 'https://github.com/CocoaPods/Specs.git'
- [!] Error installing DoubleConversion
pod install
Analyzing dependencies
Fetching podspec for `DoubleConversion` from `../node_modules/react-native/third-party-podspecs/DoubleConversion.podspec`
Fetching podspec for `Folly` from `../node_modules/react-native/third-party-podspecs/Folly.podspec`
Fetching podspec for `glog` from `../node_modules/react-native/third-party-podspecs/glog.podspec`
Downloading dependencies
Installing CocoaAsyncSocket (7.6.4)
Installing CocoaLibEvent (1.0.0)
Installing DoubleConversion (1.1.6)
[!] Error installing DoubleConversion
[!] /usr/bin/git clone https://github.com/google/double-conversion.git /var/folders/sf/kwbyjr2s6wq9t8709gzdj3xr0000gp/T/d20200703-81977-16us9f4 --template= --single-branch --depth 1 --branch v1.1.6
Cloning into '/var/folders/sf/kwbyjr2s6wq9t8709gzdj3xr0000gp/T/d20200703-81977-16us9f4'...
error: RPC failed; curl 56 LibreSSL SSL_read: SSL_ERROR_SYSCALL, errno 54
fatal: the remote end hung up unexpectedly
fatal: early EOF
fatal: unpack-objects failed
A:
https://www.jianshu.com/p/7b21254cbd77
作者的方式过于复杂，从评论区发现一个对我有效的方式(也是出自于作者，作者看来没少尝试)：无脑重试下。
langkee
2019.12.27 16:58
多尝试几次，最近一段时间，cocoapods不稳定，这个我一些朋友也遇到，都是不断尝试，手动下载只是增加成功率。另外，如果还是不行，退出终端，电脑重启一下再试试，有时候可能有缓存影响。
Android
iOS成功运行proj后，试试terminal 运行 android
1、 error Failed to install the app. Make sure you have the Android development...
yarn android
yarn run v1.22.4
$ react-native run-android
info Running jetifier to migrate libraries to AndroidX. You can disable it using "--no-jetifier" flag.
Jetifier found 960 file(s) to forward-jetify. Using 4 workers...
info Starting JS server...
info Installing the app...
FAILURE: Build failed with an exception.
* What went wrong:
Could not initialize class org.codehaus.groovy.runtime.InvokerHelper
* 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 3s
error Failed to install the app. Make sure you have the Android development environment set up: https://reactnative.dev/docs/environment-setup. Run CLI with --verbose flag for more details.
Error: Command failed: ./gradlew app:installDebug -PreactNativeDevServerPort=8081
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
Solution:
参考了🤚 https://www.e-learn.cn/topic/2636273 回答1
Open the android project(folder) in the Android Studio IDE.
All errors with your environment will show up
于是，使用Android Studio打开proj即可暴露。
果然有报错提示
Received close_notify during handshake
A:
https://blog.csdn.net/lxy1740/article/details/104606385/
在项目的build.gradle文件中将jcenter()换成阿里的源。
// jcenter()
maven{ url'http://maven.aliyun.com/nexus/content/groups/public/' }
maven{ url'http://maven.aliyun.com/nexus/content/repositories/jcenter'}
修改之后再重新Sync Project，见效了，几分钟提示ok。于是run到模拟器。然后build成功，并调起模拟器。
2、 E/wifi_forwarder: RemoteConnection failed to initialize: RemoteConnection failed to open pipe
LogCat中出现的标红部分：
2020-07-03 16:33:56.337 448-448/? E/wifi_forwarder: RemoteConnection failed to initialize: RemoteConnection failed to open pipe
2020-07-03 16:33:56.543 410-410/? E/netmgr: Failed to open QEMU pipe 'qemud:network': Invalid argument
找到个类似的，但 其实不是解决方案。
couldn't find DSO to load: libjscexecutor.so caused by: dlopen failed: library "libjsc.so" not found #25537
A：
yarn react-native start
这个有效，终端执行这句后，再使用Android Studio就可以成功运行到模拟器调试了，我曾经用了yarn android，正好那次失败了，所以 里面包括的yarn react-native start命令没有执行
后来一直用的Android Studio解决错误，在线调试就出问题了。
重新查看文档，发现确实有提醒 有坑
终于，可以 ①用Android Studio 成功运行项目到模拟器 。以为一切迎刃而解，但。。。
3、无法通过Android Studio或命令行 运行到真机上，也无法使用命令行 正常启动项目在模拟器。
BUILD FAILED in 6s
error Failed to install the app. Make sure you have the Android development environment set up: https://reactnative.dev/docs/environment-setup. Run CLI with --verbose flag for more details.
Error: Command failed: ./gradlew app:installDebug -PreactNativeDevServerPort=8081
java.lang.NoClassDefFoundError: Could not initialize class org.codehaus.groovy.vmplugin.v7.Java7
对照文档https://reactnative.cn/docs/getting-started 查看，发现JDK版本必须是1.8（或称JDK8），晕！
就是这个原因，我(曾经)装了最新的
$javac -version
javac 14.0.1
A:
再装一个吧，两个就两个jdk呗，下载安装jdk8后。需要设置好.bash_profile（环境变量）
# JDK1.8
export JAVA_8_HOME='/Library/Java/JavaVirtualMachines/jdk1.8.0_251.jdk/Contents/Home'
# JDK14
export JAVA_14_HOME='/Library/Java/JavaVirtualMachines/jdk-14.0.1.jdk/Contents/Home'
# react-native配置 限定是 JDK1.8
export JAVA_HOME=$JAVA_8_HOME
使得当前使用的jdk是1.8的，检查如下
$javac -version
javac 1.8.0_251
终于， ②命令行启动app到模拟器，success ！
图片.png
然后，③退出模拟器 ，命令行启动app到真机，success ！
测试下热重装AOT，通过修改App.js修改内容 然后保存(cmd + S), 真机app内容立刻刷新，perfect！
最后，④Android Studio 启动app到真机，success ！
当然，还有挫折。当越过③ 尝试④时，一直失败。报错与本文Q2一样
448-448/? E/wifi_forwarder: RemoteConnection failed to initialize: RemoteConnection failed to open pipe 410-410/? E/netmgr: Failed to open QEMU pipe 'qemud:network': Invalid argument(其实)当进行过一次③之后，以后执行④就没问题了。
至此，命令行、Android Studio 与 模拟器、真机，两两组合调试 全都搞定，可以放心做后续的事情了。
4、在Android Studio里的Terminal，是无法成功运行app到模拟器/真机的，也是醉了。。。
BUILD FAILED in 969ms
error Failed to install the app. Make sure you have the Android development environment set up: https://reactnative.dev/docs/environment-setup. Run CLI with --verbose flag for more details.
Error: Command failed: ./gradlew app:installDebug -PreactNativeDevServerPort=8081
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
然后，怀疑IDE里的terminal难道jdk版本和Mac的terminal 不一致？👇果然。。。
javac -version
javac 14.0.1
只需 重复在 Android Studio的terminal里 再执行下source ~/.bash_profile 即可
其它问题
端口被占用
这种情况，算是经常出现的吧。怪就怪 yarn有start 但没有stop命令，不知道咋stop的；所以有时 停止调试 却没法关掉8081的socket，当下次调试时就会发生出现问题。
yarn start
error listen EADDRINUSE: address already in use :::8081. Run CLI with --verbose flag for more details.
Error: listen EADDRINUSE: address already in use :::8081
强制kill掉
//查出PID，是19665
sudo lsof -i:8081
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
node 19665 dl 24u IPv6 0x6a20760fbf7c0ca9 0t0 TCP *:sunproxyadmin (LISTEN)
//kill掉 PID
sudo kill -9 19665
