###Problem Description: because the SDK manager has been installed before, after setting the Android SDK location to the Android SDK installation directory, the SDK Tools Directory is missing error is still reported

The error content is shown in the figure

###Solutions

Online solutions are generally discussed around the proxy setting problem, but I didn’t appear the page of download or download failure in the configuration process, so I ruled out this problem. Problems with the SDK can also be eliminated, because the SDK has been used in other Android projects before, and there is no problem. Finally, after some groping, we finally solved the problem. The problem may be that jjdk is not configured. The solution is as follows:

Open the project structure settings directory

Then configure JDK and SDK

If you forget the JDK installation directory, you can use the command line java - verb to view it in the last line of the result

After the configuration is completed, you can enter the SDK manager again to operate