Android Studio 3.6.1 error when i hook frame layout with autocomplete

Question

Hello I just want to switch from a fragment to another using a button. Nothing difficult... the code works well but I have spent a lot of time because Android goesto error if I hook frameLayout with autocompile. I'm explaining better:

package com.example.fragcookbook;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;

public class MainActivity extends AppCompatActivity {

    FragmentOne mFragmentOne;
    FragmentTwo mFragmentTwo;
    int showingFragment=0;

    @Override
    protected void onCreate ( Bundle savedInstanceState ) {
        super.onCreate (savedInstanceState);
        setContentView (R.layout.activity_main);
        mFragmentOne = new FragmentOne();
        mFragmentTwo = new FragmentTwo();
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.frameLayout, mFragmentOne);
        fragmentTransaction.commit();
        showingFragment=1;

    }
    public void switchFragment(View view) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        if (showingFragment==1) {
            fragmentTransaction.replace(R.id.frameLayout, mFragmentTwo);
            showingFragment = 2;
        } else {
            fragmentTransaction.replace(R.id.frameLayout, mFragmentOne);
            showingFragment=1;
        }
        fragmentTransaction.commit();
    }

In all rows where you see R.id.frameLayout i have to handly write frameLayout..... Android colors it red but It works...

But if i choose the resource with autocompile...

...when i run app Android gives me this error....

Why? is not best practice use autocompile? Thanks in advance

Answer 1

Try this may will help you.Go to "File" -> "Invalidate Caches...", and select "Invalidate and Restart" option to fix this.

Or

Restar you android studio and emulator