CollapsingToolbarLayout不承认滚动一扔 [英] CollapsingToolbarLayout doesn't recognize scroll fling

问题描述

我创建了一个简单的 Col​​lapsingToolbarLayout 和它的作品就像一个魅力。我的问题是，如果我尝试使用一扔滚动的 nestedscrollview ，当我松开我的手指刚刚停止。正常滚动的作品像它应该。

我的活动code是 不变=>自动的产生的空活动。 （我刚刚点击创建机器人工作室新的空活动，并编辑XML还）。

我在这里阅读，滚动手势的ImageView的本身有Bug，但是没有，那滚动本身有错误：<一href="https://$c$c.google.com/p/android/issues/detail?id=176673">https://$c$c.google.com/p/android/issues/detail?id=176673

我试图激活的的平滑滚动的通过Java code。好像如果我滚动远远不够的ImageView的不可见了，一扔手势则是公认的。

TLDR：为什么一扔手势不是只要ImageView的是可见的工作？ 我的XML code是这样的：

 ＆LT; android.support.design.widget.CoordinatorLayout
    的xmlns：机器人=htt​​p://schemas.android.com/apk/res/android
    的xmlns：程序=htt​​p://schemas.android.com/apk/res-auto
    机器人：layout_width =match_parent
    机器人：layout_height =match_parent
    机器人：fitsSystemWindows =真正的＆GT;

    ＆LT; android.support.design.widget.AppBarLayout
        机器人：ID =@ + ID / profile_app_bar_layout
        机器人：layout_width =match_parent
        机器人：layout_height =WRAP_CONTENT
        机器人：主题=@风格/ ThemeOverlay.AppCompat.Dark.ActionBar
        机器人：fitsSystemWindows =真正的＆GT;

        ＆LT; android.support.design.widget.CollapsingToolbarLayout
            机器人：ID =@ + ID / profile_collapsing_toolbar_layout
            机器人：layout_width =match_parent
            机器人：layout_height =match_parent
            应用程序：layout_scrollFlags =滚动| exitUntilCollapsed
            应用程序：contentScrim =？ATTR / colorPrimary
            应用程序：expandedTitleMarginStart =48dp
            应用程序：expandedTitleMarginEnd =64dp
            机器人：fitsSystemWindows =真正的＆GT;

            ＆LT; ImageView的
                机器人：ID =@ + ID /图像
                机器人：layout_width =match_parent
                机器人：layout_height =420dp
                机器人：scaleType =centerCrop
                机器人：fitsSystemWindows =真
                机器人：SRC =@可绘制/ headerbg
                机器人：=了maxHeight192dp

                应用程序：layout_collapseMode =视差/＆GT;

            ＆LT; android.support.v7.widget.Toolbar
                机器人：ID =@ + ID /工具栏
                机器人：layout_width =match_parent
                机器人：layout_height =？ATTR / actionBarSize
                应用程序：popupTheme =@风格/ ThemeOverlay.AppCompat.Light
                应用程序：layout_collapseMode =针/＆GT;

        ＆LT; /android.support.design.widget.CollapsingToolbarLayout>

    ＆LT; /android.support.design.widget.AppBarLayout>

    ＆LT; android.support.design.widget.FloatingActionButton
        机器人：ID =@ + ID /晶圆厂
        应用程序：layout_anchor =@ ID / profile_app_bar_layout
        应用程序：layout_anchorGravity =底部|右|结束
        机器人：layout_height =@扪/ fab_size_normal
        机器人：layout_width =@扪/ fab_size_normal
        应用程序：海拔=2DP
        应用程序：pressedTranslationZ =12dp
        机器人：layout_marginRight =8DP
        机器人：layout_marginEnd =8DP/＆GT;

    ＆LT; android.support.v4.widget.NestedScrollView
        机器人：ID =@ + ID / profile_content_scroll
        机器人：layout_width =match_parent
        机器人：layout_height =match_parent
        机器人：clipToPadding =假
        应用程序：layout_behavior =@字符串/ appbar_scrolling_view_behavior
        机器人：layout_gravity =fill_vertical
        机器人：=了minHeight192dp
        机器人：overScrollMode =ifContentScrolls
        ＆GT;

        ＆LT; RelativeLayout的
            机器人：layout_width =match_parent
            机器人：layout_height =WRAP_CONTENT＆GT;

            ＆LT;的TextView
                机器人：layout_width =match_parent
                机器人：layout_height =WRAP_CONTENT
                机器人：文本=@字符串/ LoremIpsum/＆GT;

        ＆LT; / RelativeLayout的＆GT;

    ＆LT; /android.support.v4.widget.NestedScrollView>

＆LT; /android.support.design.widget.CoordinatorLayout>
 

解决方案

从答：

<一个href="http://stackoverflow.com/a/32454407/2281718">http://stackoverflow.com/a/32454407/2281718

这解决了这个问题对我来说。创建一个自定义的 AppBarLayout.Behavior 是这样的：

 公开最后一类FlingBehavior扩展AppBarLayout.Behavior {
    私有静态最终诠释TOP_CHILD_FLING_THRESHOLD = 3;
    私人布尔isPositive;

    公共FlingBehavior（）{
    }

    公共FlingBehavior（上下文的背景下，ATTRS的AttributeSet）{
        超（背景下，ATTRS）;
    }

    @覆盖
    公共布尔onNestedFling（CoordinatorLayout coordinatorLayout，AppBarLayout孩子，查看目标，浮velocityX，浮velocityY，布尔消耗）{
        如果（velocityY大于0＆安培;＆安培;！isPositive || velocityY＆℃，安培;＆安培; isPositive）{
            velocityY = velocityY * -1;
        }
        如果（目标的instanceof RecyclerView＆安培;＆安培; velocityY℃，）{
            最后RecyclerView recyclerView =（RecyclerView）的目标;
            最终视图则firstChild = recyclerView.getChildAt（0）;
            最终诠释childAdapterPosition = recyclerView.getChildAdapterPosition（则firstChild）;
            消费= childAdapterPosition＆GT; TOP_CHILD_FLING_THRESHOLD;
        }
        返回super.onNestedFling（coordinatorLayout，儿童，目标，velocityX，velocityY，消耗）;
    }

    @覆盖
    公共无效onNested preScroll（CoordinatorLayout coordinatorLayout，AppBarLayout孩子，查看目标，INT DX，DY INT，INT []消耗）{
        super.onNested preScroll（coordinatorLayout，儿童，目标，DX，DY，消耗）;
        isPositive = DY＆GT; 0;
    }
}
 

和它添加到 AppBarLayout 是这样的：

 ＆LT; android.support.design.widget.AppBarLayout
        机器人：layout_width =match_parent
        机器人：layout_height =WRAP_CONTENT
        ...
        应用程序：layout_behavior =com.example.test.FlingBehavior＆GT;
 

I have created a simple CollapsingToolbarLayout and it works like a charm. My problem is, that if I try to use a fling scroll on the nestedscrollview, it just stops when I release my finger. Normal scrolling works like it should.

My activities code is unchanged => auto generated empty activity. (I just clicked on create new empty activity in android studio and edited the XML yet).

I read here, that scroll gestures on the imageview itself are buggy, but not, that the scrolling itself is buggy: https://code.google.com/p/android/issues/detail?id=176673

I tried activating "smooth scrolling" through java code. It seems like if I scroll far enough that the imageview isn't visible anymore, fling gestures then are recognized.

TLDR: Why does the fling gesture not work as long as the imageview is visible ? My XML Code looks like this:

    <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:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/profile_app_bar_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
        android:fitsSystemWindows="true">

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

            <ImageView
                android:id="@+id/image"
                android:layout_width="match_parent"
                android:layout_height="420dp"
                android:scaleType="centerCrop"
                android:fitsSystemWindows="true"
                android:src="@drawable/headerbg"
                android:maxHeight="192dp"

                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.design.widget.FloatingActionButton
        android:id="@+id/fab"
        app:layout_anchor="@id/profile_app_bar_layout"
        app:layout_anchorGravity="bottom|right|end"
        android:layout_height="@dimen/fab_size_normal"
        android:layout_width="@dimen/fab_size_normal"
        app:elevation="2dp"
        app:pressedTranslationZ="12dp"
        android:layout_marginRight="8dp"
        android:layout_marginEnd="8dp"/>

    <android.support.v4.widget.NestedScrollView
        android:id="@+id/profile_content_scroll"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clipToPadding="false"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        android:layout_gravity="fill_vertical"
        android:minHeight="192dp"
        android:overScrollMode="ifContentScrolls"
        >

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="@string/LoremIpsum"/>

        </RelativeLayout>

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

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

解决方案

Answer from:

http://stackoverflow.com/a/32454407/2281718

which solved this problem for me. Create a custom AppBarLayout.Behavior like this:

public final class FlingBehavior extends AppBarLayout.Behavior {
    private static final int TOP_CHILD_FLING_THRESHOLD = 3;
    private boolean isPositive;

    public FlingBehavior() {
    }

    public FlingBehavior(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean onNestedFling(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, float velocityX, float velocityY, boolean consumed) {
        if (velocityY > 0 && !isPositive || velocityY < 0 && isPositive) {
            velocityY = velocityY * -1;
        }
        if (target instanceof RecyclerView && velocityY < 0) {
            final RecyclerView recyclerView = (RecyclerView) target;
            final View firstChild = recyclerView.getChildAt(0);
            final int childAdapterPosition = recyclerView.getChildAdapterPosition(firstChild);
            consumed = childAdapterPosition > TOP_CHILD_FLING_THRESHOLD;
        }
        return super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed);
    }

    @Override
    public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, int dx, int dy, int[] consumed) {
        super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed);
        isPositive = dy > 0;
    }
}

and add it to the AppBarLayout like this:

<android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        ...
        app:layout_behavior="com.example.test.FlingBehavior">

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