RecyclerView 正在切断最后一项 [英] RecyclerView is cutting off the last item

问题描述

我有一个片段，里面有一个工具栏和一个 recyclerView.

I have a fragment with a toolbar and a recyclerView inside it.

我正在用虚拟数据填充 recyclerView，然后尝试显示它们.出于某种原因，recyclerView 的最后一个元素被截断了.

I am populating the recyclerView with dummy data and then try to show them. For some reason, the last element of the recyclerView is getting cut-off.

这是片段的 XML:

<?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:background="@color/background_1"
    android:fitsSystemWindows="true">

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

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

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

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

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

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

    <android.support.v7.widget.RecyclerView
        android:id="@+id/simpleList"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

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

列表中的项目非常简单:

The items at the list are really simple ones:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="200dp"
    android:background="@color/background_1"
    android:orientation="horizontal"
    android:padding="@dimen/space_for_a_bit_of_air">

    <ImageView
        android:id="@+id/album_cover"
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:layout_gravity="center_vertical"
        android:scaleType="fitXY"
        android:src="@drawable/placeholder_album_cover"/>

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_vertical"
        android:layout_marginLeft="@dimen/space_for_distinguishing_stuff"
        android:orientation="vertical">

        <TextView
            android:id="@+id/album_title"
            style="@style/titleText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/sample_text_c"/>

        <TextView
            android:id="@+id/album_year"
            style="@style/subtitleText"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="@string/sample_text_a"/>

    </LinearLayout>

</LinearLayout>

我现在在列表的末尾，但最后一个元素看起来仍然被截断.

I am now at the end of the list, but the last element still looks cut-off.

我使用的是 2015 年 9 月 23 日 google 库的最新版本，23.0.1，(即 com.android.support:recyclerview-v7:23.0.1)，以及 build.gradle 中的以下配置:

I am using the latest version as of 2015-09-23 of google libraries, 23.0.1, (i.e. com.android.support:recyclerview-v7:23.0.1), and the following configuration at the build.gradle:

compileSdkVersion 23
buildToolsVersion "23.0.1"

defaultConfig {
   minSdkVersion 14
   targetSdkVersion 23
   versionCode 1
   versionName "1.0"

   multiDexEnabled true// Enabling multidex support
 }

任何帮助将不胜感激，因为我对这个问题很着迷:(

Any help would be greatly appreciated since I am going nuts with this problem :(

好的，在将代码清理到基本要素并去除复杂性之后，我发现了问题:这是错误标志和缺失或额外属性的组合.以下适用于 Android 4.x 和 5.x:

Ok, after cleaning the code to the bare essentials and removing complexity, I found the problem: it was a combination of wrong flags and missing or extra attributes. The following works fine for both Android 4.x and 5.x:

<?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"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/background_1"
    android:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout
        android:id="@+id/appbar_layout"
        android:layout_width="match_parent"
        android:layout_height="@dimen/height_of_app_bar"
        android:fitsSystemWindows="true">

        <android.support.design.widget.CollapsingToolbarLayout
            android:id="@+id/collapsing_toolbar"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:fitsSystemWindows="true"
            app:collapsedTitleTextAppearance="@style/Title.collapsed"
            app:contentScrim="@color/primary"
            app:expandedTitleMarginStart="48dp"
            app:expandedTitleTextAppearance="@style/Title.Expanded"
            app:layout_scrollFlags="scroll|enterAlways|enterAlwaysCollapsed">

            <ImageView
                android:id="@+id/backdrop"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:fitsSystemWindows="true"
                android:scaleType="centerCrop"
                android:src="@drawable/artistic_4"
                app:layout_collapseMode="parallax"/>

            <View
                android:layout_width="match_parent"
                android:layout_height="@dimen/height_of_app_bar"
                android:background="@drawable/gradient"/>

            <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.design.widget.CollapsingToolbarLayout>

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

    <android.support.v7.widget.RecyclerView
        android:id="@+id/simpleList"
        style="@style/genericRecyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        tools:listitem="@layout/item_discography_album"/>

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

简而言之，android:fitsSystemWindows="true" 应该只在 coordinatorLayout、AppBarLayout 和 theCollapsingToolbarLayout(这是我们希望在 Android 5.x 上根据屏幕调整的那些)，app:layout_scrollFlags应该设置为scroll|enterAlways|enterAlwaysCollapsed"并且工具栏的高度应该是actionBar的高度.最后，最好保持 RecyclerView 尽可能干净，以便您可以控制每个行项目的布局间距.

In a nutshell, android:fitsSystemWindows="true" should only be at the coordinatorLayout, AppBarLayout and theCollapsingToolbarLayout (which are the ones that we want to be adjusted based on the screen on Android 5.x), the app:layout_scrollFlags should be set to "scroll|enterAlways|enterAlwaysCollapsed" and the toolbar should have as height, the height of the actionBar. Finally, it's better to keep the RecyclerView as clean as possible so you can control the layout spacing at each line item.

推荐答案

尝试将您的 RecyclerView 高度更改为 "wrap_content" 并添加 AppBarLayout 高度作为边距底部.

Try to change your RecyclerView height to "wrap_content" and add the AppBarLayout height as margin bottom.

<android.support.v7.widget.RecyclerView
        android:id="@+id/simpleList"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="@dimen/height_of_app_bar"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"/>

列表项的截断部分，是AppBarLayout的高度.

The cut-off part of the list item, is the height of the AppBarLayout.

这篇关于RecyclerView 正在切断最后一项的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！