阻止FAB改变其大小

Question

我已将浮动操作按钮锚定到折叠工具栏。当我的活动开始时，我的FAB是正常大小并固定在右下角。

当我折叠工具栏时，FAB消失。

我宁愿保留FAB，也不要在工具栏崩溃时消失。我不知道该怎么做。任何人都可以帮我解决这个问题吗？

我的布局：

 <android.support.design.widget.CoordinatorLayout 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"
    android:background="@android:color/background_light"
    android:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/main.appbar"
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        android:fitsSystemWindows="true"
        >
        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/main_collapsing"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            app:contentScrim="?attr/colorPrimary"
            >

            <ImageView
                android:id="@+id/photo"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:scaleType="centerCrop"
                android:fitsSystemWindows="true"
                app:layout_collapseMode="parallax"
                />

            <android.support.v7.widget.Toolbar
                android:id="@+id/main.toolbar"
                android:layout_width="match_parent"
                android:layout_height="?attr/actionBarSize"
                app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
                app:layout_collapseMode="pin"
                />
        </android.support.design.widget.CollapsingToolbarLayout>
    </android.support.design.widget.AppBarLayout>

    <android.support.v4.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        >

        <TextView
            android:id="@+id/article_body"
            style="?android:attr/textAppearanceMedium"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:padding="16dp"
            android:textSize="20sp"
            android:lineSpacingMultiplier="@fraction/detail_body_line_spacing_multiplier" />
    </android.support.v4.widget.NestedScrollView>

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/share_fab"
        android:stateListAnimator="@anim/fab_state_list_anim"
        android:background="@drawable/add_fab_background"
        android:layout_marginRight="@dimen/fab_margin"
        android:layout_width="56dp"
        android:layout_height="56dp"
        android:src="@drawable/ic_share"
        android:elevation="@dimen/fab_elevation"
        android:contentDescription="@string/action_share"
        app:layout_anchor="@id/main.appbar"
        app:layout_anchorGravity="bottom|right|end"/>

</android.support.design.widget.CoordinatorLayout>

Answer 1

尝试在 FloatingActionButton

中进行小幅更改

<android.support.design.widget.FloatingActionButton
        android:id="@+id/share_fab"
        android:stateListAnimator="@anim/fab_state_list_anim"
        android:background="@drawable/add_fab_background"
        android:layout_marginRight="@dimen/fab_margin"
        android:layout_width="56dp"
        android:layout_height="56dp"
        android:src="@drawable/ic_share"
        android:elevation="@dimen/fab_elevation"
        android:contentDescription="@string/action_share"
        app:layout_anchor="@id/main_collapsing"
        app:layout_anchorGravity="bottom|right|end"/>