问题一：该问题在创建新项目后报错
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.
解决①：检查build.gradle(Module:app)文件的 compileSdkVersion 与 targetSdkVersion 版本是否一致
解决②：Build > Rebuild Project