android - 如何根据滚动方向折叠/展开 View ？

Question

我在 LinearLayout 中有一个 View 和一个 RecyclerView。我想要实现的是这样的:

https://material.google.com/patterns/scrolling-techniques.html#scrolling-techniques-behavior

基本上，当我向上滚动 RecyclerView 时，View 会折叠。如果我向下滚动 RecyclerView，它会展开。

我已经尝试过各种方法，但如果手指在滚动位置周围猛拉，动画就会断断续续。只有当手指在一个方向上有意识地滚动时，它才能很好地动画。我该如何正确执行此操作？

Answer 1

您必须将 Coordinator Layout 与 CollapsingToolbarLayout 一起使用

<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:clipToPadding="false">

<android.support.design.widget.AppBarLayout
    android:id="@+id/app_bar_layout"
    android:layout_width="match_parent"
    android:layout_height="210dp"
    android:stateListAnimator="@animator/appbar_always_elevated" //I put this here because I want to have shadow when is open, but you have to create the xml file.
    android:background="@color/WHITE">

    <android.support.design.widget.CollapsingToolbarLayout
        android:id="@+id/collapsing_toolbar_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:collapsedTitleTextAppearance="@style/TextAppearance.AppCompat.Widget.ActionBar.Title.Inverse"
        app:expandedTitleMarginStart="72dp"
        app:expandedTitleTextAppearance="@style/TextAppearance.AppCompat.Widget.ActionBar.Title.Inverse"
        app:layout_scrollFlags="scroll|exitUntilCollapsed"> //HERE you should take a look what you want your collapse bar do.

        <Here you put the content for you collapse bar, like a ImageView>

        <android.support.v7.widget.Toolbar //This is the size of your fixed bar when you collapse, even here you can put a back button, for example
            android:id="@+id/app_bar"
            android:layout_width="match_parent"
            android:layout_height="40dp"
            app:layout_collapseMode="pin" />
    </android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>

<android.support.v4.widget.SwipeRefreshLayout
    android:id="@+id/main_home_list_swipe"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior" >

    <android.support.v7.widget.RecyclerView
        android:id="@+id/main_home_list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

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

Obs:如果你放在一个xml文件中，注释会出错。正在提议，所以你会记得阅读哈哈哈