滚动 CoordinatorLayout 时如何防止底部导航隐藏

Question

I added a ListView with a collapsing toolbar at the top and bottom navigation at the bottom. My problem is that the bottom navigation keeps hiding when scrolling up. I want it to stay visible. I enabled nested scrolling programmatically. I tried many solutions, none of them worked.

This is my problem and my XML at the bottom:

This my main.xml

<androidx.coordinatorlayout.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/_coordinator"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true">
    <com.google.android.material.appbar.AppBarLayout
        android:id="@+id/_app_bar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">
        <com.google.android.material.appbar.CollapsingToolbarLayout
            android:id="@+id/collapse"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:contentScrim="#000000"
            android:fitsSystemWindows="true"
            app:layout_scrollFlags="scroll|enterAlways|snap">
            <LinearLayout
                android:id="@+id/header"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:padding="8dp"
                android:gravity="center_horizontal|center_vertical"
                android:orientation="horizontal">
                <TextView
                    android:id="@+id/textview1"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:padding="8dp"
                    android:text="collapsing toolbar"
                    android:textSize="20sp"
                    android:textColor="#FFFFFF"/>
            </LinearLayout>
            <androidx.appcompat.widget.Toolbar
                android:id="@+id/_toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="?attr/colorPrimary"
                app:popupTheme="@style/AppTheme.PopupOverlay"/>
        </com.google.android.material.appbar.CollapsingToolbarLayout>
    </com.google.android.material.appbar.AppBarLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">
        <ListView
            android:id="@+id/listview1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:choiceMode="none"
            android:layout_weight="1"/>
        <LinearLayout
            android:id="@+id/nav"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="8dp"
            android:background="#1565C0"
            android:gravity="center_horizontal|center_vertical"
            android:orientation="horizontal">
            <TextView
                android:id="@+id/textview2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:padding="8dp"
                android:text="bottom navigation"
                android:textSize="20sp"
                android:textColor="#FFFFFF"/>
        </LinearLayout>
    </LinearLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

Answer 1

use a ConstraintLayout as a Root ViewGroup , and wrap in it the CoordinatorLayout , and the BottomNavigation

Then you can need to add some padding at the end of the ListView

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.coordinatorlayout.widget.CoordinatorLayout
        android:id="@+id/_coordinator"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true">

        <com.google.android.material.appbar.AppBarLayout
            android:id="@+id/_app_bar"
            android:layout_width="match_parent"
             android:theme="@style/AppTheme.AppBarOverlay"
            android:layout_height="wrap_content">
           
            <com.google.android.material.appbar.CollapsingToolbarLayout
                android:id="@+id/collapse"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:fitsSystemWindows="true"
                app:contentScrim="#000000"
                app:layout_scrollFlags="scroll|enterAlways|snap">

                <androidx.appcompat.widget.Toolbar
                    android:id="@+id/_toolbar"
                    android:layout_width="match_parent"
                    android:layout_height="?attr/actionBarSize"
                    android:background="?attr/colorPrimary" 
                    app:popupTheme="@style/AppTheme.PopupOverlay"/>

                <LinearLayout
                    android:id="@+id/header"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:gravity="center_horizontal|center_vertical"
                    android:orientation="horizontal"
                    android:padding="8dp">

                    <TextView
                        android:id="@+id/textview1"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:padding="8dp"
                        android:text="collapsing toolbar"
                        android:textColor="#FFFFFF"
                        android:textSize="20sp" />
                </LinearLayout>


            </com.google.android.material.appbar.CollapsingToolbarLayout>
        </com.google.android.material.appbar.AppBarLayout>

        <ListView
            android:id="@+id/listview1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:choiceMode="none"
            app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    </androidx.coordinatorlayout.widget.CoordinatorLayout>

    <LinearLayout
        android:id="@+id/nav"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:background="#1565C0"
        android:gravity="center"
        android:orientation="horizontal"
        android:padding="8dp"
        app:layout_constraintBottom_toBottomOf="parent">

        <TextView
            android:id="@+id/textview2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="8dp"
            android:text="bottom navigation"
            android:textColor="#FFFFFF"
            android:textSize="20sp" />
    </LinearLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

RelativeLayout version

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.coordinatorlayout.widget.CoordinatorLayout
        android:id="@+id/_coordinator"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true">

        <com.google.android.material.appbar.AppBarLayout
            android:id="@+id/_app_bar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:theme="@style/AppTheme.AppBarOverlay">

            <com.google.android.material.appbar.CollapsingToolbarLayout
                android:id="@+id/collapse"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:fitsSystemWindows="true"
                app:contentScrim="#000000"
                app:layout_scrollFlags="scroll|enterAlways|snap">

                <androidx.appcompat.widget.Toolbar
                    android:id="@+id/_toolbar"
                    android:layout_width="match_parent"
                    android:layout_height="?attr/actionBarSize"
                    android:background="?attr/colorPrimary"
                    app:popupTheme="@style/AppTheme.PopupOverlay" />

                <LinearLayout
                    android:id="@+id/header"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:gravity="center_horizontal|center_vertical"
                    android:orientation="horizontal"
                    android:padding="8dp">

                    <TextView
                        android:id="@+id/textview1"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:padding="8dp"
                        android:text="collapsing toolbar"
                        android:textColor="#FFFFFF"
                        android:textSize="20sp" />
                </LinearLayout>


            </com.google.android.material.appbar.CollapsingToolbarLayout>
        </com.google.android.material.appbar.AppBarLayout>

        <ListView
            android:id="@+id/listview1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:choiceMode="none"
            app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    </androidx.coordinatorlayout.widget.CoordinatorLayout>

    <LinearLayout
        android:id="@+id/nav"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:background="#1565C0"
        android:gravity="center"
        android:orientation="horizontal"
        android:padding="8dp"
        app:layout_constraintBottom_toBottomOf="parent">

        <TextView
            android:id="@+id/textview2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:padding="8dp"
            android:text="bottom navigation"
            android:textColor="#FFFFFF"
            android:textSize="20sp" />
    </LinearLayout>

</RelativeLayout>

Preview (replace ListView with NestedScrollView for simplicity)