title: React Native BUILD FAILED Execution failed for task ':app:installDebug'
body: <h2><strong>I'm getting the following error when i run the cmd > react-native run-android Guide me to fix this issue.</strong></h2>
  
  <pre><code>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.
  
  BUILD FAILED
  
  Total time: 1 mins 27.72 secs
  Could not install the app on the device, read the error above for details.
  Make sure you have an Android emulator running or a device connected and have
  set up your Android development environment:
  https://facebook.github.io/react-native/docs/android-setup.html
  </code></pre>