سلام و احترام

من فکر میکنم در فایل styles.xml مربوط به پروژتون این تکه خط زیر مربوط به Theme به اشتباه * بدون NoActionBar ست کردین

اگر چنین چیزی نبود لطفا کد xml مربوطه به لیوت detail رو بفرستید

<style name="AppTheme" parent="Theme.MaterialComponents.Light.NoActionBar">

 سلام نخیر دقیقا همین کد رو زدم 

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/white"
    xmlns:app="http://schemas.android.com/apk/res-auto"
  >
    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <com.google.android.material.appbar.CollapsingToolbarLayout
            android:id="@+id/collapsingToolbarLayout_detail"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:theme="@style/Theme.MaterialComponents"
            app:contentScrim="@color/colorPrimary"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            >
            <ImageView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:src="@drawable/dsd"
                app:layout_collapseMode="parallax"
                android:adjustViewBounds="true"/>
            <androidx.appcompat.widget.Toolbar
                android:id="@+id/toolbar_detail"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"/>
        </com.google.android.material.appbar.CollapsingToolbarLayout>
    </com.google.android.material.appbar.AppBarLayout>
    <androidx.core.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingStart="12dp"
        android:paddingEnd="12dp"
        app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="12dp"
                android:layout_marginBottom="8dp"
                android:textSize="16sp"
                android:textStyle="bold"
                android:textColor="@android:color/black"
                android:text="Lorem Ipsum is simply dummy text"/>
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.
\n
It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English. Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like).\n
There are many variations of passages of Lorem Ipsum available, but the majority have suffered alteration in some form, by injected humour, or randomised words which don't look even slightly believable. If you are going to use a passage of Lorem Ipsum, you need to be sure there isn't anything embarrassing hidden in the middle of text. All the Lorem Ipsum generators on the Internet tend to repeat predefined chunks as necessary, making this the first true generator on the Internet. It uses a dictionary of over 200 Latin words, combined with a handful of model sentence structures, to generate Lorem Ipsum which looks reasonable. The generated Lorem Ipsum is therefore always free from repetition, injected humour, or non-characteristic words etc.\n
On the other hand, we denounce with righteous indignation and dislike men who are so beguiled and demoralized by the charms of pleasure of the moment, so blinded by desire, that they cannot foresee the pain and trouble that are bound to ensue; and equal blame belongs to those who fail in their duty through weakness of will, which is the same as saying through shrinking from toil and pain. These cases are perfectly simple and easy to distinguish. In a free hour, when our power of choice is untrammelled and when nothing prevents our being able to do what we like best, every pleasure is to be welcomed and every pain avoided. But in certain circumstances and owing to the claims of duty or the obligations of business it will frequently occur that pleasures have to be repudiated and annoyances accepted. The wise man therefore always holds in these matters to this principle of selection: he rejects pleasures to secure other greater pleasures, or else he endures pains to avoid worse pains."
                android:textColor="@android:color/black"/>
        </LinearLayout>
    </androidx.core.widget.NestedScrollView>

یه سری اتربیوت‌ها فراموش کرده بودید بذارید مثلا در toolbar فراموش کرده بودید mode رو مشخص کنین 

پس من ویرایش کردم اینم کد ویرایشی:

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/white"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <com.google.android.material.appbar.AppBarLayout
        android:id="@+id/appBar_detail"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
        <com.google.android.material.appbar.CollapsingToolbarLayout
            android:id="@+id/collapsingToolbarLayout_detail"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:theme="@style/Theme.MaterialComponents"
            app:contentScrim="@color/colorPrimary"
            app:layout_scrollFlags="scroll|exitUntilCollapsed">
            <ImageView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:src="@drawable/image_top"
                app:layout_collapseMode="parallax"
                android:adjustViewBounds="true"/>
            <androidx.appcompat.widget.Toolbar
                android:id="@+id/toolbar_detail"
                android:layout_width="match_parent"
                android:layout_height="56dp"
                app:layout_collapseMode="pin"
                />
        </com.google.android.material.appbar.CollapsingToolbarLayout>
    </com.google.android.material.appbar.AppBarLayout>
    <androidx.core.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:paddingStart="12dp"
        android:paddingEnd="12dp"
        app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="12dp"
                android:layout_marginBottom="8dp"
                android:textSize="16sp"
                android:textStyle="bold"
                android:textColor="@android:color/black"
                android:text="Lorem Ipsum is simply dummy text"/>
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.
\n
It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English. Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like).\n
There are many variations of passages of Lorem Ipsum available, but the majority have suffered alteration in some form, by injected humour, or randomised words which don't look even slightly believable. If you are going to use a passage of Lorem Ipsum, you need to be sure there isn't anything embarrassing hidden in the middle of text. All the Lorem Ipsum generators on the Internet tend to repeat predefined chunks as necessary, making this the first true generator on the Internet. It uses a dictionary of over 200 Latin words, combined with a handful of model sentence structures, to generate Lorem Ipsum which looks reasonable. The generated Lorem Ipsum is therefore always free from repetition, injected humour, or non-characteristic words etc.\n
On the other hand, we denounce with righteous indignation and dislike men who are so beguiled and demoralized by the charms of pleasure of the moment, so blinded by desire, that they cannot foresee the pain and trouble that are bound to ensue; and equal blame belongs to those who fail in their duty through weakness of will, which is the same as saying through shrinking from toil and pain. These cases are perfectly simple and easy to distinguish. In a free hour, when our power of choice is untrammelled and when nothing prevents our being able to do what we like best, every pleasure is to be welcomed and every pain avoided. But in certain circumstances and owing to the claims of duty or the obligations of business it will frequently occur that pleasures have to be repudiated and annoyances accepted. The wise man therefore always holds in these matters to this principle of selection: he rejects pleasures to secure other greater pleasures, or else he endures pains to avoid worse pains."
                android:textColor="@android:color/black"/>
        </LinearLayout>
    </androidx.core.widget.NestedScrollView>
    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/fab_detail"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@drawable/ic_add_white_24dp"
        app:layout_anchor="@id/appBar_detail"
        app:layout_anchorGravity="end|bottom"
        app:useCompatPadding="true"
        style="@style/Widget.Design.FloatingActionButton"
        app:fabSize="mini"/>
    <com.google.android.material.floatingactionbutton.ExtendedFloatingActionButton
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|center"
        android:layout_marginBottom="24dp"
        app:icon="@drawable/ic_layers_24dp"
        android:text="@string/app_name"/>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

همچنین دقت کنین فایل styles.xml به صورت کد‌های زیر باشه به  NoActionBar دقت کنید

<resources>
    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.MaterialComponents.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorSecondary">@color/colorAccent</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorOnSecondary">@android:color/white</item>
    </style>
</resources>

و همچنین کد‌های زیر در MainFragment.java به درستی نوشته شده باشد 

Toolbar toolbar=view.findViewById(R.id.toolbar_main);
        toolbar.setNavigationIcon(R.drawable.ic_menu_white_24dp);
        AppCompatActivity appCompatActivity= (AppCompatActivity) getActivity();
        appCompatActivity.setSupportActionBar(toolbar);

مجموع این موارد باعث میشوند اون تولبار به درستی کار کند

از انجایی که من نسبت به کد‌های نوشته شده توسط شما اطلاعی ندارم به همین دلیل سعی کردم تمام مشکلاتی که ممکن هست باعث این مورد بشن رو در نظر گرفتم و واستون نوشتم 

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