【Android】[Problem]-"Waiting for target device to come online".

• 環境：

  win10專業版（創意者），Android studio 2.3.1

• 問題描述:

  安裝玩Android studio之后創建一個項目，建立AVD之后，運行程序時一直不能啟動AVD，具體描述為：”Waiting for target device to come online”。即“等待目標設備在線”。

• 問題分析：

  分析1：此處參考了Android 中 adb 相關問題一文，出現此問題的原因大多是因為adb的端口被占用（eclipse，模擬器等）。

  分析2：也可能有這種問題，博主就是這種問題，參考了 “waiting for target device to come online” in Android Studio 2.3 一文

• 問題解決：

  分析1：命令行（win+r–cmd）定位到android_sdk/platform-tools/目錄下,執行”adb kill-server”

  分析2：I was also having the same issue 2 days ago when i update my android studio, today I solve my issue when I was playing around with settings then I saw that in my SDK tools setting Android Emulator is uncheck so I simply checked that box and now emulator is working fine. 
  Try this steps may work for you also: 
  Go to SDK tools > SDK Tools 
  Check Android Emulator and click Apply