title: Display an error while debug the flutter App in vscode
body: <p>I can't debug my Flutter App in Vscode , and DEBUG CONSOL returned :</p>
  
  <blockquote>
    <p>Unable to locate a development device; please run 'flutter doctor' for
    information about installing additional components.</p>
  </blockquote>
  
  <p>I can show my emulator after run this : </p>
  
  <blockquote>
    <p>flutter emulators</p>
  </blockquote>
  
  <p>And i can run it : </p>
  
  <blockquote>
    <p>flutter emulators --launch 4.7_WXGA_API_22</p>
  </blockquote>
  
  <p>flutter doctor -v :</p>
  
  <pre><code>[✓] Flutter (Channel stable, v1.7.8+hotfix.4, on Linux, locale en_US.UTF-8)
      • Flutter version 1.7.8+hotfix.4 at /home/ZZZ/Dev/Flutter/flutter
      • Framework revision 20e59316b8 (10 days ago), 2019-07-18 20:04:33 -0700
      • Engine revision fee001c93f
      • Dart version 2.4.0
  
  
  [✓] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
      • Android SDK at /media/ZZZ/B0B8B687B8B64C1A/Dev_ubuntu/android-sdk-linux/
      • Android NDK location not configured (optional; useful for native profiling support)
      • Platform android-28, build-tools 28.0.3
      • ANDROID_HOME = /media/ZZZ/B0B8B687B8B64C1A/Dev_ubuntu/android-sdk-linux/
      • Java binary at: /usr/local/android-studio/jre/bin/java
      • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b16-5323222)
      • All Android licenses accepted.
  
  [✓] Android Studio (version 3.4)
      • Android Studio at /usr/local/android-studio
      • Flutter plugin version 37.1.1
      • Dart plugin version 183.6270
      • Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1343-b16-5323222)
  
  [✓] VS Code (version 1.36.1)
      • VS Code at /usr/share/code
      • Flutter extension version 3.2.0
  
  [✓] Connected device (1 available)
      • Android SDK built for x86 • emulator-5554 • android-x86 • Android 5.1.1 (API 22) (emulator)
  
  • No issues found!
  </code></pre>
  
  <p>My operating system is Ubuntu 18.04 and i want to use emulator for debug , please help me.</p>