Error message
Unable to resolve dependency for ':app@debug/compileClasspath': Could not resolve com.android.support.constraint:constraint-layout:2.0.2. <a href="disable.gradle.offline.mode">Disable offline mode and sync project</a><br><a href="Unable to resolve dependency for ':app@debug/compileClasspath': Could not resolve com.android.support.constraint:constraint-layout:2.0.2.">Show Details</a> Affected Modules: <a href="openFile:D:/android3/app/build.gradle">app</a>
Solution:
Change the root directory build.gradle(:app) (注意是带app后缀的)
to the following
