React-Native：错误无法安装应用程序。确保您有正在运行的 Android 模拟器

Question

我刚刚通过以下方式初始化了一个新的 React Native 项目：

react-native init AwesomeProject

我已经收到此错误：

BUILD FAILED in 3s

error Failed to install the app. Make sure you have an Android emulator running or a device connected. Run CLI with --verbose flag for more details.
Error: Command failed: ./gradlew app:installDebug -PreactNativeDevServerPort=8081

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:installDebug'.
> com.android.builder.testing.api.DeviceException: No connected devices!

* 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

    at checkExecSyncError (child_process.js:637:11)
    at execFileSync (child_process.js:655:13)
    at runOnAllDevices (/Users/danale/Projects/engageMobile/node_modules/@react-native-community/cli-platform-android/build/commands/runAndroid/runOnAllDevices.js:75:39)
    at buildAndRun (/Users/danale/Projects/engageMobile/node_modules/@react-native-community/cli-platform-android/build/commands/runAndroid/index.js:169:41)
    at then.result (/Users/danale/Projects/engageMobile/node_modules/@react-native-community/cli-platform-android/build/commands/runAndroid/index.js:135:12)
    at processTicksAndRejections (internal/process/next_tick.js:81:5)

到目前为止，它只是一个样板应用程序。我使用 zsh 而不是 bash 作为命令行界面。

我也在 flutter 中开发，但没有遇到这个问题，它可以顺利打开 Nexus 5X 模拟器。

可能是什么问题呢？

我尝试更改权限，但不是这样。

Answer 1

所以显然我ios比android自动react-native run-ios为您打开模拟器有更多的经验，react-native run-android但重要的是，类似的命令，不要做类似的事情，即打开模拟器。

一旦我在 Android Studio 中打开应用程序，然后转到AVD Manager，打开 Android Studio 的模拟器，然后运行react-native run-android，它就完美运行了。