这是 28 版的问题，请降级到 27 版，直到问题解决.

This is an issue of version 28, you should downgrade to version 27 until the problem is solved.

转到您的应用程序/Gradle Scripts/build.gradle (Module:app)

Go to your app/Gradle Scripts/build.gradle (Module:app)

1

改变这一行:

compileSdkVersion 28

到

compileSdkVersion 27

2

改变这一行:

targetSdkVersion 28

到

targetSdkVersion 27

3

改变这一行:

implementation 'com.android.support:appcompat-v7:28.0.0-rc02'

到

implementation 'com.android.support:appcompat-v7:27.1.1'

然后 Android Studio 会要求您同步文件，您可以点击立即同步

Then Android Studio will ask you to Sync the files, and you do so by clicking in Sync Now

继续学习如何编码，很快 Android 就会解决这个问题.您可以在此处查看有关此讨论的更多信息一>.

Keep learning how to code, and soon Android will solve this problem. You can see more about this discussion here.