出现的问题
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.
解决方式
在build.gradle中将
implementation 'com.android.support:appcompat-v7:26.1.0' androidTestImplementation 'com.android.support:support-annotations:26.1.0'
修改为：
implementation 'com.android.support:appcompat-v7:27.1.1'
androidTestImplementation 'com.android.support:support-annotations:27.1.1'