Ambiguous method call. Both findViewById (int) in AppCompactActivity and Activity

Question

I refer this link Error : Ambiguous method call. Both findViewById (int) in AppCompactActivity and Activity to solve but there is no import android.app.Activity and also if I convert my import android.support.v7.app.AppCompatActivity into android.app.Activity then the error goes but I want to use AppCompatActivity.

I also update all libraries in SDK and also invalidate and restart but nothing works.

why this error occurs and how to solve this?

Answer 1

I guess you have something like that

ViewClass view = (ViewClass)findViewById(R.id.view);

in your code and you'd updated API level? If so, change your code to

ViewClass view = findViewById(R.id.view); // without redundant cast

The findViewById method signature was changed in API 25, please refer to SDK

Answer 2

If you recently updated your project to API 26, try doing invalidate caches/restart, then re-sync gradle.