如何使工具栏的背景透明

问：

我设置了一个折叠工具栏，一切都按预期工作。只有一个问题，当工具栏折叠时，工具栏后面有一个白色的矩形视图，如下图所示。以下是activity_home.xml文件的代码

<?xml version="1.0" encoding="utf-8"?>
<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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".HomeActivity">

    <com.google.android.material.appbar.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@android:color/transparent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <com.google.android.material.appbar.CollapsingToolbarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:background="@android:color/transparent"
            app:contentScrim="@drawable/custom_app_bar_background"
            app:expandedTitleTextAppearance="@style/expandedTitleTextAppearance"
            app:layout_scrollFlags="scroll|snap|exitUntilCollapsed">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="300dp"
                android:background="@drawable/custom_app_bar_background"
                android:paddingHorizontal="20dp"
                android:orientation="vertical">

                <TextView
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="40dp"
                    android:text="Empowering Discovery: Search the Database for a World of Information"
                    android:textColor="@color/white"
                    android:textSize="30sp"
                    android:textStyle="bold"/>

                <TextView
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:layout_marginTop="10dp"
                    android:text="Search The Database"
                    android:textColor="#c9d3f7"
                    android:textSize="20sp" />

                <EditText
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:height="50dp"
                    android:hint="Search for media..."
                    android:paddingStart="20dp"
                    android:textColor="@color/black"
                    android:layout_marginTop="10dp"
                    android:drawableEnd="@drawable/search_btn"
                    android:paddingRight="5dp"
                    android:background="@drawable/search_bar_background"/>

            </LinearLayout>
            
            <androidx.appcompat.widget.Toolbar
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                android:background="@drawable/gradient"
                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="match_parent"
        app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:gravity="center"
            android:textSize="25sp"
            android:text="If you're looking to remove the default white background that appears while your app initializes, there isn't a direct way to remove it completely, as it's part of the Android system behavior. However, you can make it less noticeable or disguise it using various techniques. Here are a few alternatives:

1. Use a Splash Screen:
As mentioned earlier, using a splash screen with your app's branding or logo can provide a smoother transition. The splash screen gives the impression that something is happening during the initialization phase, making the white background less noticeable.

2. Optimize Initialization:
Efficiently optimize your app's initialization process. Load essential resources lazily and asynchronously. Delay resource-heavy operations until after the main activity has started. By optimizing your initialization, the white background period is minimized, making it less noticeable.

3. Set a Theme with Transparent Background:
In your app's theme, set the background to be transparent. This doesn't remove the white background but makes it less noticeable since the default background will be transparent instead of white. Add the following line to your theme in styles.xml:"/>

    </androidx.core.widget.NestedScrollView>

</androidx.coordinatorlayout.widget.CoordinatorLayout>

以下是用于工具栏背景的渐变 .xml 文件代码：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">

    <gradient
        android:angle="120"
        android:endColor="@android:color/transparent"
        android:startColor="#3BB1EC" />

</shape>

以下是在折叠工具栏展开时用作 CollapsingToolbarLayout 和 Linear 布局背景的稀松布的 custom_app_bar_background.xml 文件的代码：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">

    <gradient
        android:startColor="#3BB1EC"
        android:endColor="#216CF1"
        android:angle="120"/>

    <corners
        android:bottomRightRadius="40dp"
        android:bottomLeftRadius="40dp"/>

</shape>

我尝试将工具栏的背景设置为透明，但不起作用，因为状态栏颜色与工具栏颜色没有顺利混合。目标是删除工具栏后面的白色矩形视图，如上图所示。