折叠工具栏不隐藏所有

Question

我希望能够做到这一点我知道这是一个 CollapsingToolbarLayout 但我不知道如何让一些想法在远处停下来，感谢您的帮助

the result I want to get

Answer 1

实现折叠工具栏的简单示例。

<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.support.design.widget.AppBarLayout
    android:id="@+id/app_bar_layout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <android.support.design.widget.CollapsingToolbarLayout
        android:id="@+id/collapsing_toolbar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_scrollFlags="scroll|exitUntilCollapsed"
        app:contentScrim="?attr/colorPrimary">

        <ImageView
            android:id="@+id/expandedImage"
            android:layout_width="match_parent"
            android:layout_height="200dp"
            android:src="@drawable/beach_scene"

            android:scaleType="centerCrop"
            app:layout_collapseMode="parallax"
         app:layout_collapseParallaxMultiplier="0.7"
            />

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            app:layout_collapseMode="pin" >


        </android.support.v7.widget.Toolbar>


    </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"
    android:background="@android:color/white"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">


        <TextView
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:text="@string/sample_string"/>

</android.support.v4.widget.NestedScrollView>

根据您的要求替换 ImageView 内的图像，该图像在工具栏展开时可见。 视图的其余部分可以根据您的要求在 NestedScrollView 中实现。

Answer 2

不要忘记将以下属性提供给您的FloatingActionButton

 app:layout_anchor="@id/appBar"
 app:layout_anchorGravity="bottom|end" 

尝试这样的事情：几乎与您的要求相似

<android.support.design.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"
    android:fitsSystemWindows="true"
    tools:context="com.sample.foo.usingcoordinatorlayout.FabAndSnackbarActivity">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/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/collapsingToolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            android:fitsSystemWindows="true"
            app:contentScrim="?attr/colorPrimary"
            app:expandedTitleMarginStart="48dp"
            app:expandedTitleMarginEnd="64dp"
            app:title="@string/collapsing_toolbar">

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

            <android.support.v7.widget.Toolbar
                android:id="@+id/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:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:textSize="28sp"
            android:lineSpacingExtra="8dp"
            android:text="@string/long_latin"
            android:padding="@dimen/activity_horizontal_margin" />
    </android.support.v4.widget.NestedScrollView>

    <android.support.design.widget.FloatingActionButton
        android:layout_height="wrap_content"
        android:layout_width="wrap_content"
        android:layout_margin="@dimen/activity_horizontal_margin"
        android:src="@drawable/mascot_icon"
        app:layout_anchor="@id/appBar"
        app:layout_anchorGravity="bottom|end" />
</android.support.design.widget.CoordinatorLayout>