对于在iOS上使用CocoaPods遇到同样问题的其他人:

我尝试了上面所有的解决方案，但运气不佳。我在我的项目中有一些本地依赖的包，其中一些需要的pod模块正在安装。问题是React是在我的Podfile中指定的，但是React pod并没有通过使用React -native-git-upgrade自动升级。

修复方法是通过运行cd ios && pod install来升级所有已安装的pod。

我更新了react-native版本:0.57.4到0.59.8，我得到以下消息“react-native版本不匹配”

这个解决方案对我来说很有效:

1.- In the folder of the project, update all the code react-native in the Android Studio:

react-native bundle --platform android --dev false --entry-file index.js --bundle-output android/app/src/main/assets/index.android.bundle --assets-dest android/app/src/main/res/

2.- Go to Android Studio and FILE->>INVALIDATE CACHES/RESTART
3.- In Android Studio, BUILD->>CLEAN PROJECT
4.- In Android Studio, BUILD->>REBUILD PROJECT
5.- Delete App in simulator or Devices
6.- Run...

希望对大家有所帮助!

如果你用create-react-native-app创建react-native-app。你应该有一个app.json (expo)。还有一个包裹。Json文件，检查世博版本是否匹配并相应更改。例如，在我的案例中，问题是在app.json文件中，我有一个25.0.0版本的expo sdkVersion属性，我将其更改为23.0.0，一切正常工作。

package.json:

"dependencies": {
    "expo": "^23.0.4",
    "react": "16.0.0",
    "react-native": "^0.50.4"
  }

app.json:

{
  "expo": {
    "sdkVersion": "23.0.0" // before was 25.0.0
  }
}

这对我来说很管用:

react-native start --reset-cache

I've never seen this error before, but whenever I can't get Xcode and React-Native to play well together, I do a couple of things. Check what version of Xcode I'm working with. If it needs to be updated, I update it. Then clearing watchman and the cache are the second place I go. I don't use the reset cache command. It always says that I need to verify the cache, so I skip that (you can do it though, I just get confused). I use rm -rf $TMPDIR/react-* to get rid of any cached builds. If that doesn't work, I try to build the app in Xcode, then work my way from there, to build it with react-native run-ios. With this error message, it seems you might start by trying to build it with Xcode. Hope that helps...let me know your progress with it. Good luck! (Also, you could update to RN 0.51 as another attempt to get your versions synced.)

还要确保在模拟器中启用了wifi