no target device found android studio 2.1.1

I already had this problem before.

Choose "Run" then "Edit Configurations". In the "General" tab, check the "Deployment Target Options" section.

In my case, the target was already set to "USB Device" and the checkbox "Use same device for future launches" was checked.

I had to change the target to "Show Device Chooser Dialog" and I unchecked the check box. Then my device appeared in the list.

If your device still doesn't appear, then you have to enable USB-Debugging in the smartphone settings again.

go to "Run>edit configuration>" and select "Open select deployment target dialog" from deployment target option then run your app it will show you a dialog box you can choose your target device from there, enjoy it.

trick that works for me when target device not found:

• click the "attach debugger to android process" button. (that will enable adb integration for you)

• click the run button