com.google.android.material.appbar.AppBarLayout$LayoutParams cannot be cast to androidx.coordinatorlayout.widget.CoordinatorLayout$LayoutParams

Question

I've used CoordinatorLayout + AppBarLayout so the Toolbar could disappear while scrolling and to put Recycler View below tablayout. But after I've changed model logic and added child elements in the toolbar this fatal error keeps happening. After changing the root layout to LinearLayout or FrameLayout the error disappears, but I don't get desired behavior. I don't call, create or change my Layout params for AppBarLayout and CoordinatorLayout in the code (MainActivity). So the stack trace does not show me any internal lines of code, just the internal classes logic. Here is the XML:

<androidx.coordinatorlayout.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/container"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">


<com.google.android.material.appbar.AppBarLayout
    android:id="@+id/appBarLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:contentInsetStart="0dp"
        app:layout_scrollFlags="scroll|snap"
        app:titleTextColor="@android:color/white">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal">

            <ImageView
                android:id="@+id/toolbarBackButton"
                android:layout_width="?attr/actionBarSize"
                android:layout_height="?attr/actionBarSize"
                android:visibility="invisible"/>

            <TextView
                android:id="@+id/toolbarText"
                android:layout_width="0dp"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:background="@color/colorPrimary"
                android:fontFamily="sans-serif-medium"
                android:gravity="center_vertical"
                android:text="@string/activity_main_toolbar_title"
                android:textColor="@android:color/white"
                android:textSize="20sp" />

            <ImageView
                android:id="@+id/toolbarBucket"
                android:layout_width="?attr/actionBarSize"
                android:layout_height="?attr/actionBarSize" />
        </LinearLayout>
    </androidx.appcompat.widget.Toolbar>

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/tabs"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:tabBackground="@color/colorPrimary"
        app:tabIndicatorColor="@color/colorIndicator"
        app:tabSelectedTextColor="@color/colorActive"
        app:tabTextColor="@color/colorInactive" />
</com.google.android.material.appbar.AppBarLayout>

<androidx.viewpager2.widget.ViewPager2
    android:id="@+id/viewPager"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    app:layout_anchor="@id/tabs"
    app:layout_anchorGravity="bottom"
    app:layout_behavior="@string/appbar_scrolling_view_behavior" />

<com.google.android.material.floatingactionbutton.FloatingActionButton
    android:id="@+id/add_fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|right"
    android:layout_margin="@dimen/regularMargin"
    android:src="@drawable/ic_baseline_add_24"
    app:tint="@android:color/white"/></androidx.coordinatorlayout.widget.CoordinatorLayout>

Any clues will be much appreciated! My main activity code

package com.example.loftmoney.screens.main;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.fragment.app.Fragment;
import androidx.viewpager2.widget.ViewPager2;

import android.content.Intent;
import android.os.Bundle;

import com.example.loftmoney.R;
import com.example.loftmoney.model.Item;
import com.example.loftmoney.screens.additem.AddItemActivity;
import com.example.loftmoney.screens.balance.BalanceFragment;
import com.example.loftmoney.screens.budget.BudgetFragment;
import com.example.loftmoney.screens.main.adapter.FragmentItem;
import com.example.loftmoney.screens.main.adapter.MainPagerAdapter;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.tabs.TabLayout;
import com.google.android.material.tabs.TabLayoutMediator;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity implements MainClickAdapter, EditModeListener {

    private ViewPager2 viewPager;
    private Toolbar toolbar;
    TabLayout tabs;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setupFab();
        setupTabs();
        setupToolbar();
    }

    private void setupToolbar() {
        toolbar = findViewById(R.id.toolbar);
    }

    private void setupTabs() {
        List<FragmentItem> fragments = setupFragments();

        tabs = findViewById(R.id.tabs);
        viewPager = findViewById(R.id.viewPager);
        MainPagerAdapter adapter = new MainPagerAdapter(fragments, this, 0);//behavior?
        viewPager.setOffscreenPageLimit(fragments.size());
        viewPager.setAdapter(adapter);

        new TabLayoutMediator(tabs, viewPager,
                (tab, position) -> tab.setText(
                        fragments.get(position).getTitle()
                )
        ).attach();
    }

    private List<FragmentItem> setupFragments() {
        List<FragmentItem> fragments = new ArrayList();
        fragments.add(new FragmentItem(new BudgetFragment(), getString(R.string.expenses), Item.ItemType.EXPENSE));
        fragments.add(new FragmentItem(new BudgetFragment(), getString(R.string.incomes), Item.ItemType.INCOME));
        fragments.add(new FragmentItem(new BalanceFragment(), getString(R.string.balance)));
        return fragments;
    }

    private Fragment getActiveFragment() {
        final int activeFragmentIndex = viewPager.getCurrentItem();
        Fragment activeFragment = (BudgetFragment) getSupportFragmentManager().getFragments().get(activeFragmentIndex);
        return activeFragment;
    }

    private void setupFab() {
        FloatingActionButton addFab = findViewById(R.id.add_fab);
        addFab.setOnClickListener(v -> onFabClick());
    }

    @Override
    public void onFabClick() {
        BudgetFragment activeFragment = (BudgetFragment) getActiveFragment();
        Intent intent = new Intent(MainActivity.this, AddItemActivity.class).putExtra("type", activeFragment.type);
        activeFragment.startActivityForResult(intent, BudgetFragment.LAUNCH_ADD_ITEM);
    }

    @Override
    public void onEditModeChangeListener(boolean status) {
        toolbar.setBackgroundColor(getApplicationContext().getColor(
                status ? R.color.editModeColor : R.color.colorPrimary));
    }
}

Answer 1

This was because I've set up an anchor. I've deleted these 2 lines and all works fine

app:layout_anchor="@id/tabs"
app:layout_anchorGravity="bottom"