Error:Execution failed for task ':app:preDebugAndroidTestBuild'.
> Conflict with dependency 'com.android.support:support-annotations' in project ':app'.
Resolved versions for app (26.1.0) and test app (27.1.1) differ.
See https://d.android.com/r/tools/test-apk-dependency-conflicts.html for details.
将app目录下的build.gradle以下几项做些修改
implementation 'com.android.support.constraint:constraint-layout:1.1.2'
==>
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
==>
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
==>
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
