title: React Native, why react-native run-android not working?
body: <p>I'm trying to run react native run-android after I update my project file, but whenever I run <code>react-native</code> it throws an error. When I created that project and that command it worked fine but when I edit and add some files like apps/redux, apps/components, screens etc it stopped working. Can anyone tell me why it's not working?</p>
  <pre><code>error Failed to launch emulator. Reason: Could not start emulator within 30 seconds..
  warn Please launch an emulator manually or connect a device. Otherwise app may fail to launch.
  info Installing the app...
  
  &gt; Task :app:compileDebugJavaWithJavac
  
  &gt; Task :app:stripDebugDebugSymbols UP-TO-DATE
  Compatible side by side NDK version was not found.
  
  &gt; Task :app:installDebug FAILED
  
  Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
  Use '--warning-mode all' to show the individual deprecation warnings.
  See https://docs.gradle.org/6.3/userguide/command_line_interface.html#sec:command_line_warnings
  27 actionable tasks: 6 executed, 21 up-to-date
  Note: C:\Users\Danger World\ReactProject\android\app\src\debug\java\com\reactproject\ReactNativeFlipper.java uses or overrides a deprecated API.
  Note: Recompile with -Xlint:deprecation for details.
  
  FAILURE: Build failed with an exception.
  
  * What went wrong:
  Execution failed for task ':app:installDebug'.
  &gt; 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 1m 11s
  
  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.bat app:installDebug -PreactNativeDevServerPort=8081
  Note: C:\Users\Danger World\ReactProject\android\app\src\debug\java\com\reactproject\ReactNativeFlipper.java uses or overrides a deprecated API. 
  </code></pre>