First Android Tutorial Project Error

I got error messages like this on DisplayMessageActivity.java

Error:(17, 6) Gradle: error: cannot find symbol class SuppressLint
Error:(37, 9) Gradle: error: cannot find symbol class Intent
Error:(41, 9) Gradle: error: cannot find symbol class TextView
Error:(41, 33) Gradle: error: cannot find symbol class TextView

import android.annotation.SuppressLint;
import android.content.Intent;
import android.widget.TextView;