Android-在CoordinatorLayout中使用时，页脚在屏幕上滚动 [英] Android - footer scrolls off screen when used in CoordinatorLayout

问题描述

我有一个AppBarLayout，当滚动RecyclerView时，它会在屏幕外滚动. 在RecyclerView下面是一个RelativeLayout，它是一个页脚.

仅在向上滚动后才显示页脚-行为类似于

layout_scrollFlags="scroll|enterAlways"

但它没有任何滚动标志-是bug还是我做错了事?我希望它始终可见

滚动之前

滚动后

更新

为此打开了一个 google问题-已将其标记为'WorkingAsIntended'仍然无济于事，因为我想要一个片段内页脚的有效解决方案.

更新2

您可以在此处找到活动和xmls

请注意，如果activity.xml中的第34行-包含app:layout_behavior="@string/appbar_scrolling_view_behavior"的行被注释掉，则文本 end 从一开始就可见-否则，仅在向上滚动

解决方案

我使用Learn OpenGL ES解决方案的简化版本( https://stackoverflow.com/a/33396965/778951 )-改进了Noa的解决方案( https://stackoverflow. com/a/31140112/1317564 ).对于我在TabLayout上方的简单快速返回工具栏，每个选项卡的ViewPager内容中均带有页脚按钮，它可以很好地工作.

只需将FixScrollingFooterBehavior设置为要在屏幕底部保持对齐的View/ViewGroup上的layout_behavior.

布局:

<?xml version="1.0" encoding="utf-8"?>
<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/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?android:attr/actionBarSize"
                android:minHeight="?android:attr/actionBarSize"
                app:title="Foo"
                app:layout_scrollFlags="scroll|enterAlways|snap"
                />

            <android.support.design.widget.TabLayout
                android:id="@+id/tabs"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:tabMode="fixed"/>

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

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="com.spreeza.shop.ui.widgets.FixScrollingFooterBehavior"
        />

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

行为:

public class FixScrollingFooterBehavior extends AppBarLayout.ScrollingViewBehavior {

    private AppBarLayout appBarLayout;

    public FixScrollingFooterBehavior() {
        super();
    }

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

    @Override
    public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {

        if (appBarLayout == null) {
            appBarLayout = (AppBarLayout) dependency;
        }

        final boolean result = super.onDependentViewChanged(parent, child, dependency);
        final int bottomPadding = calculateBottomPadding(appBarLayout);
        final boolean paddingChanged = bottomPadding != child.getPaddingBottom();
        if (paddingChanged) {
            child.setPadding(
                child.getPaddingLeft(),
                child.getPaddingTop(),
                child.getPaddingRight(),
                bottomPadding);
            child.requestLayout();
        }
        return paddingChanged || result;
    }


    // Calculate the padding needed to keep the bottom of the view pager's content at the same location on the screen.
    private int calculateBottomPadding(AppBarLayout dependency) {
        final int totalScrollRange = dependency.getTotalScrollRange();
        return totalScrollRange + dependency.getTop();
    }
}

I have an AppBarLayout that scrolls off screen when scrolling a RecyclerView. Below the RecyclerView there is a RelativeLayout that is a footer.

The footer is shown only after scrolling up - it behave like it has

layout_scrollFlags="scroll|enterAlways"

but it doesn't have any scroll flags - is it a bug or am I doing something wrong? I want it to be always visible

before scroll

after scroll

Update

opened a google issue on this - it was marked 'WorkingAsIntended' this still doesn't help because I want a working solution of a footer inside a fragment.

Update 2

you can find the activity and the fragment xmls here -

note that if line 34 in activity.xml - the line containing app:layout_behavior="@string/appbar_scrolling_view_behavior" is commented out the text end is visible from the start - otherwise, it is visible only after scrolling up

解决方案

I use a simplified version of Learn OpenGL ES's solution (https://stackoverflow.com/a/33396965/778951) -- which improves on Noa's solution (https://stackoverflow.com/a/31140112/1317564). It works fine for my simple quick-return toolbar above a TabLayout with footer buttons in each tab's ViewPager content.

Just set the FixScrollingFooterBehavior as the layout_behavior on the View/ViewGroup you want to keep aligned at the bottom of the screen.

Layout:

<?xml version="1.0" encoding="utf-8"?>
<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/appbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

            <android.support.v7.widget.Toolbar
                android:id="@+id/toolbar"
                android:layout_width="match_parent"
                android:layout_height="?android:attr/actionBarSize"
                android:minHeight="?android:attr/actionBarSize"
                app:title="Foo"
                app:layout_scrollFlags="scroll|enterAlways|snap"
                />

            <android.support.design.widget.TabLayout
                android:id="@+id/tabs"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                app:tabMode="fixed"/>

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

    <android.support.v4.view.ViewPager
        android:id="@+id/viewpager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="com.spreeza.shop.ui.widgets.FixScrollingFooterBehavior"
        />

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

Behavior:

public class FixScrollingFooterBehavior extends AppBarLayout.ScrollingViewBehavior {

    private AppBarLayout appBarLayout;

    public FixScrollingFooterBehavior() {
        super();
    }

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

    @Override
    public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {

        if (appBarLayout == null) {
            appBarLayout = (AppBarLayout) dependency;
        }

        final boolean result = super.onDependentViewChanged(parent, child, dependency);
        final int bottomPadding = calculateBottomPadding(appBarLayout);
        final boolean paddingChanged = bottomPadding != child.getPaddingBottom();
        if (paddingChanged) {
            child.setPadding(
                child.getPaddingLeft(),
                child.getPaddingTop(),
                child.getPaddingRight(),
                bottomPadding);
            child.requestLayout();
        }
        return paddingChanged || result;
    }


    // Calculate the padding needed to keep the bottom of the view pager's content at the same location on the screen.
    private int calculateBottomPadding(AppBarLayout dependency) {
        final int totalScrollRange = dependency.getTotalScrollRange();
        return totalScrollRange + dependency.getTop();
    }
}

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