如何根据滚动方向折叠/展开视图? [英] How to collapse/expand a view based on scroll direction?

问题描述

我在LinearLayout中装有一个View和一个RecyclerView.我想要实现的是这样的:

I have a View and a RecyclerView housed in a LinearLayout. What I want to achieve is something like this:

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

基本上，当我向上滚动RecyclerView时，该视图会折叠.如果我向下滚动RecyclerView，它会扩展.

Basically when I scroll the RecyclerView up, the View collapses. It expands if I scroll the RecyclerView down.

我尝试了各种方法，但是如果手指在滚动位置附近晃动，动画会结结巴巴.如果手指在一个方向上进行了故意的滚动移动，则动画效果良好.如何正确执行此操作?

I've tried various methods but the animation stutters if the finger jerks around a scroll position. It only animates well if the finger does a deliberate scroll movement in one direction. How do I do this correctly?

推荐答案

您必须在ColapsingToolbarLayout中使用协调器布局

You have to use Coordinator Layout with the CollapsingToolbarLayout

<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 >

糟糕:如果放置在xml文件中，注释将给出错误.正在提议中，因此您将记住阅读哈哈哈哈

Obs: the comments will give errors if you put on a xml file. Is on propose so you will remember to read hahahah

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