这对我很有效

博览会更新39.0.0 -npm

因为我的expo版本是38(Check in package.json)。

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.)

这是我对它所做的:

关闭所有终端并再次运行构建。

你可能忘记从另一个项目关闭nodejs终端，而他们碰巧安装了不同的react版本。

因此，从nodejs服务器获取的代码与本机代码冲突。

我已经尝试了上面的解决方案，但将此添加到AndroidManifest.xml似乎可以修复它。

  android:usesCleartextTraffic="true"

对我来说，这是由于包的依赖项部分的反应本机版本。json文件。它是:

"dependencies": {
"expo": "^27.0.1",
"react": "16.3.1",
"react-native": "~0.55.0"
}

我把它改成:

"dependencies": {
"expo": "^27.0.1",
"react": "16.3.1",
"react-native": "0.52.0"
}

现在它工作得很好。

关闭nodejs终端，重新构建。