title: Android Sutido 3.4 problem of including jni.h
body: <p>I upgrade Android Studio 3.2 to 3.4 and encounter a problem. 
  Add a <code>test.cpp</code> source file to CMakelist and Sync project but it doesn't work. Android Studio prompt me:</p>
  
  <blockquote>
    <p>This file is not part of the project. Please include it int the appropriate build file(build.gradle, CMakeList.txt or Android.mk etc) and sync the project</p>
  </blockquote>
  
  <p>When I build the project. the cpp source works. and when I include <code>jni.h</code>. the <code>jni.h</code> has red alert. But compiles for no problem. The existing cpp files have no such problem. They include <code>jni.h</code> successfully and have no red alert. 
  Could you tell me what happens. Does Android Studio 3.4 have a bug?</p>