如何在RecyclerView中的项目之间添加分隔符和空格？
这是以前在ListView课程中使用分隔符和 dividerHeight 参数完成的示例：
<ListView
android:id="@+id/activity_home_list_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:divider="@android:color/transparent"
android:dividerHeight="8dp"/>
但是，我在RecyclerView课程中没有看到这种可能性。
<android.support.v7.widget.RecyclerView
android:id="@+id/activity_home_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical"/>
在这种情况下，可以直接定义边距和/或将自定义分隔视图直接添加到列表项的布局中，还是有更好的方法来实现我的目标？
43 个答案:
答案 0 :(得分：1058)
2016年10月更新
Android支持库25.0.0版引入了DividerItemDecoration类：
DividerItemDecoration是一个RecyclerView.ItemDecoration，可用作LinearLayoutManager项之间的分隔符。它支持HORIZONTAL和VERTICAL方向。
用法：
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(),
layoutManager.getOrientation());
recyclerView.addItemDecoration(dividerItemDecoration);
上一个回答
有些答案要么使用已被弃用的方法，要么不提供完整的解决方案，所以我尝试做一个简短的最新总结。
与ListView不同，RecyclerView类没有与分隔符相关的参数。相反，您需要扩展ItemDecoration，RecyclerView的内部类：
ItemDecoration允许应用程序从适配器的数据集向特定项目视图添加特殊的绘图和布局偏移。这对于在项目，突出显示，可视分组边界等之间绘制分隔符非常有用。所有
ItemDecorations按照添加顺序绘制，在项目查看之前（onDraw()内）和项目之后（在onDrawOver（Canvas，RecyclerView中，RecyclerView.State)。
Vertical行距ItemDecoration
扩展ItemDecoration，添加自定义构造函数，将空格height作为参数并覆盖getItemOffsets()方法：
public class VerticalSpaceItemDecoration extends RecyclerView.ItemDecoration {
private final int verticalSpaceHeight;
public VerticalSpaceItemDecoration(int verticalSpaceHeight) {
this.verticalSpaceHeight = verticalSpaceHeight;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
RecyclerView.State state) {
outRect.bottom = verticalSpaceHeight;
}
}
如果您不想在最后一项下方插入空格，请添加以下条件：
if (parent.getChildAdapterPosition(view) != parent.getAdapter().getItemCount() - 1) {
outRect.bottom = verticalSpaceHeight;
}
注意：您还可以修改outRect.top，outRect.left和outRect.right属性以获得所需效果。
分隔线ItemDecoration
扩展ItemDecoration并覆盖onDraw()方法：
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
private Drawable divider;
/**
* Default divider will be used
*/
public DividerItemDecoration(Context context) {
final TypedArray styledAttributes = context.obtainStyledAttributes(ATTRS);
divider = styledAttributes.getDrawable(0);
styledAttributes.recycle();
}
/**
* Custom divider will be used
*/
public DividerItemDecoration(Context context, int resId) {
divider = ContextCompat.getDrawable(context, resId);
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
int left = parent.getPaddingLeft();
int right = parent.getWidth() - parent.getPaddingRight();
int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = parent.getChildAt(i);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
int top = child.getBottom() + params.bottomMargin;
int bottom = top + divider.getIntrinsicHeight();
divider.setBounds(left, top, right, bottom);
divider.draw(c);
}
}
}
您可以调用第一个使用默认Android分隔符属性的构造函数，也可以调用第二个使用自己的drawable属性的构造函数，例如drawable / divider.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<size android:height="1dp" />
<solid android:color="#ff992900" />
</shape>
注意：如果您希望在上项目中绘制分隔符，请改写onDrawOver()方法。
用法
要使用新课程，请将VerticalSpaceItemDecoration或DividerSpaceItemDecoration添加到RecyclerView，例如在您的片段onCreateView()方法中：
private static final int VERTICAL_ITEM_SPACE = 48;
private RecyclerView recyclerView;
private LinearLayoutManager linearLayoutManager;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_feed, container, false);
recyclerView = (RecyclerView) rootView.findViewById(R.id.fragment_home_recycler_view);
linearLayoutManager = new LinearLayoutManager(getActivity());
recyclerView.setLayoutManager(linearLayoutManager);
//add ItemDecoration
recyclerView.addItemDecoration(new VerticalSpaceItemDecoration(VERTICAL_ITEM_SPACE));
//or
recyclerView.addItemDecoration(new DividerItemDecoration(getActivity()));
//or
recyclerView.addItemDecoration(
new DividerItemDecoration(getActivity(), R.drawable.divider));
recyclerView.setAdapter(...);
return rootView;
}
还有Lucas Rocha's library，它可以简化项目装饰过程。但是哈文没试过。
其中features是：
- 库存商品装饰品的集合，包括：
- 项目间距水平/垂直分隔线。
- 列表项
答案 1 :(得分：406)
添加
recyclerView.addItemDecoration(new DividerItemDecoration(getContext(),
DividerItemDecoration.VERTICAL));
此外，您可能需要添加依赖项
compile 'com.android.support:recyclerview-v7:27.1.0'
编辑：
为了自定义它，你可以添加一个自定义drawable：
DividerItemDecoration itemDecorator = new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL);
itemDecorator.setDrawable(ContextCompat.getDrawable(getContext(), R.drawable.divider));
您可以自由使用任何自定义drawable，例如：
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid android:color="@color/colorPrimary"/>
<size android:height="0.5dp"/>
</shape>
答案 2 :(得分：247)
我可能会把你的注意力转移到Alex Fu的Github上的这个特定文件： https://gist.github.com/alexfu/0f464fc3742f134ccd1e
它是DividerItemDecoration.java示例文件＆＃34;直接从支持演示＆＃34;。（https://plus.google.com/103498612790395592106/posts/VVEB3m7NkSS）
在项目中导入此文件后，我能够很好地获得分隔线，并将其作为项目装饰添加到回收站视图中。
以下是我的onCreateView在包含Recyclerview的片段中的样子：
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_recycler_view, container, false);
mRecyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view);
mRecyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL_LIST));
mRecyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
return rootView;
}
我确定可以完成其他样式，但这是一个起点。 ：）
答案 3 :(得分：145)
简单ItemDecoration实现所有项目之间的相等空格。
public class SpacesItemDecoration extends RecyclerView.ItemDecoration {
private int space;
public SpacesItemDecoration(int space) {
this.space = space;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
outRect.left = space;
outRect.right = space;
outRect.bottom = space;
// Add top margin only for the first item to avoid double space between items
if(parent.getChildAdapterPosition(view) == 0) {
outRect.top = space;
}
}
}
答案 4 :(得分：103)
简单的一个是设置RecyclerView的背景颜色和项目的不同背景颜色。这是一个例子......
<android.support.v7.widget.RecyclerView
android:background="#ECEFF1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:scrollbars="vertical"/>
和TextView项（可以是任何东西），底边距为“x”dp或px。
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginBottom="1dp"
android:background="#FFFFFF"/>
输出......
答案 5 :(得分：41)
我认为使用简单的分隔符会对你有所帮助
为每个项目添加分隔符：
1-将其添加到可绘制目录 line_divider.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<size
android:width="1dp"
android:height="1dp" />
<solid android:color="#999999" />
</shape>
2-创建SimpleDividerItemDecoration类
我用这个例子来定义这个类：
https://gist.github.com/polbins/e37206fbc444207c0e92
package com.example.myapp;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import com.example.myapp.R;
public class SimpleDividerItemDecoration extends RecyclerView.ItemDecoration{
private Drawable mDivider;
public SimpleDividerItemDecoration(Resources resources) {
mDivider = resources.getDrawable(R.drawable.line_divider);
}
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
int left = parent.getPaddingLeft();
int right = parent.getWidth() - parent.getPaddingRight();
int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = parent.getChildAt(i);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
int top = child.getBottom() + params.bottomMargin;
int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
}
3-在使用RecyclerView的活动或片段中，在onCreateView中添加：
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
RecyclerView myRecyclerView = (RecyclerView) layout.findViewById(R.id.my_recycler_view);
myRecyclerView.addItemDecoration(new SimpleDividerItemDecoration(getResources()));
....
}
4-在项目之间添加间距
您只需要在项目视图中添加填充属性
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent"
android:padding="4dp"
>
..... item structure
</RelativeLayout>
答案 6 :(得分：29)
正如我设定ItemAnimators。 ItemDecorator不会随动画一起进入或退出。
我最终在每个项目的项目视图布局文件中都有一个视图行。它解决了我的情况。 DividerItemDecoration对于一个简单的分隔者来说，感觉太过于巫术了。
<View
android:layout_width="match_parent"
android:layout_height="1px"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:background="@color/lt_gray"/>
答案 7 :(得分：22)
由于没有正确的方法来使用Material Design正确实现这一点，我只是做了以下技巧直接在列表项上添加分隔符：
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="@color/dividerColor"/>
答案 8 :(得分：18)
这很简单，你不需要这么复杂的代码
DividerItemDecoration divider = new
DividerItemDecoration(mRVMovieReview.getContext(),
DividerItemDecoration.VERTICAL);
divider.setDrawable(
ContextCompat.getDrawable(getBaseContext(), R.drawable.line_divider)
);
mRVMovieReview.addItemDecoration(divider);
在drawable中添加：line_divider.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<size android:height="1dp" />
<solid android:color="@android:color/black" />
</shape>
答案 9 :(得分：15)
2016年10月更新
使用支持库v25.0.0，最终可以使用基本水平和垂直分隔线的默认实现！
https://developer.android.com/reference/android/support/v7/widget/DividerItemDecoration.html
答案 10 :(得分：14)
如果有人希望只添加项目之间的10dp间距，则可以通过将drawable设置为DividerItemDecoration来实现：
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(
recyclerView.getContext(),
layoutManager.getOrientation()
);
dividerItemDecoration.setDrawable(
ContextCompat.getDrawable(getContext(), R.drawable.divider_10dp)
);
其中divider_10dp是包含以下内容的可绘制资源：
<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="rectangle">
<size android:height="10dp"/>
<solid android:color="@android:color/transparent"/>
</shape>
答案 11 :(得分：11)
- 这是添加divider的简单黑客
-
只需在回收商品的布局中添加背景，如下所示
<?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="wrap_content" android:background="@drawable/shape_border" android:gravity="center" android:orientation="horizontal" android:padding="5dp"> <ImageView android:id="@+id/imageViewContactLogo" android:layout_width="60dp" android:layout_height="60dp" android:layout_marginRight="10dp" android:src="@drawable/ic_user" /> <LinearLayout android:id="@+id/linearLayout" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_weight="0.92" android:gravity="center|start" android:orientation="vertical"> <TextView android:id="@+id/textViewContactName" android:layout_width="wrap_content" android:layout_height="wrap_content" android:singleLine="true" android:text="Large Text" android:textAppearance="?android:attr/textAppearanceLarge" /> <TextView android:id="@+id/textViewStatusOrNumber" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginTop="5dp" android:singleLine="true" android:text="" android:textAppearance="?android:attr/textAppearanceMedium" /> </LinearLayout> <TextView android:id="@+id/textViewUnreadCount" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginRight="10dp" android:padding="5dp" android:text="" android:textAppearance="?android:attr/textAppearanceMedium" android:textColor="@color/red" android:textSize="22sp" /> <Button android:id="@+id/buttonInvite" android:layout_width="54dp" android:layout_height="wrap_content" android:background="@drawable/ic_add_friend" /> </LinearLayout>
在drawable文件夹中创建以下shape_border.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<gradient
android:angle="270"
android:centerColor="@android:color/transparent"
android:centerX="0.01"
android:startColor="#000" />
</shape>
这是最终结果 - 带分频器的RecyclerView。
答案 12 :(得分：10)
对于那些只在RecyclerView中寻找空间的人，请参阅我的方法，在所有项目之间获得相等的空格，除了我给出更大的第一个和最后一个项目填充。我只在水平LayoutManager左侧/右侧以及垂直LayoutManager中的顶部/底部应用填充。
public class PaddingItemDecoration extends RecyclerView.ItemDecoration {
private int mPaddingPx;
private int mPaddingEdgesPx;
public PaddingItemDecoration(Activity activity) {
final Resources resources = activity.getResources();
mPaddingPx = (int) resources.getDimension(R.dimen.paddingItemDecorationDefault);
mPaddingEdgesPx = (int) resources.getDimension(R.dimen.paddingItemDecorationEdge);
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
final int itemPosition = parent.getChildAdapterPosition(view);
if (itemPosition == RecyclerView.NO_POSITION) {
return;
}
int orientation = getOrientation(parent);
final int itemCount = state.getItemCount();
int left = 0;
int top = 0;
int right = 0;
int bottom = 0;
/** HORIZONTAL */
if (orientation == LinearLayoutManager.HORIZONTAL) {
/** all positions */
left = mPaddingPx;
right = mPaddingPx;
/** first position */
if (itemPosition == 0) {
left += mPaddingEdgesPx;
}
/** last position */
else if (itemCount > 0 && itemPosition == itemCount - 1) {
right += mPaddingEdgesPx;
}
}
/** VERTICAL */
else {
/** all positions */
top = mPaddingPx;
bottom = mPaddingPx;
/** first position */
if (itemPosition == 0) {
top += mPaddingEdgesPx;
}
/** last position */
else if (itemCount > 0 && itemPosition == itemCount - 1) {
bottom += mPaddingEdgesPx;
}
}
if (!isReverseLayout(parent)) {
outRect.set(left, top, right, bottom);
} else {
outRect.set(right, bottom, left, top);
}
}
private boolean isReverseLayout(RecyclerView parent) {
if (parent.getLayoutManager() instanceof LinearLayoutManager) {
LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
return layoutManager.getReverseLayout();
} else {
throw new IllegalStateException("PaddingItemDecoration can only be used with a LinearLayoutManager.");
}
}
private int getOrientation(RecyclerView parent) {
if (parent.getLayoutManager() instanceof LinearLayoutManager) {
LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
return layoutManager.getOrientation();
} else {
throw new IllegalStateException("PaddingItemDecoration can only be used with a LinearLayoutManager.");
}
}
}
<强> dimens.xml
<resources>
<dimen name="paddingItemDecorationDefault">10dp</dimen>
<dimen name="paddingItemDecorationEdge">20dp</dimen>
</resources>
答案 13 :(得分：10)
为您的视图添加边距，它对我有用。
android:layout_marginTop="10dp"
如果您只想添加等间距，并希望在 XML 中添加，只需将padding设置为RecyclerView等数量layoutMargin对你膨胀到RecyclerView的项目，并让背景颜色确定间距颜色。
答案 14 :(得分：10)
这实际上并没有解决问题，但作为一种临时解决方法，您可以在XML布局中设置卡上的useCompatPadding属性，使其与Lollipop前版本的测量值相同。
card_view:cardUseCompatPadding="true"
答案 15 :(得分：9)
我将DividerItemDecoration从旧的gist中分叉并简化它以适合我的用例，并且我还修改了它以在ListView中绘制它们的方式绘制分隔符，包括在最后一个列表项之后的分隔符。这也将处理垂直ItemAnimator动画：
1）将此课程添加到您的项目中：
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
private Drawable divider;
public DividerItemDecoration(Context context) {
try {
final TypedArray a = context.obtainStyledAttributes(ATTRS);
divider = a.getDrawable(0);
a.recycle();
} catch (Resources.NotFoundException e) {
// TODO Log or handle as necessary.
}
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
if (divider == null) return;
if (parent.getChildAdapterPosition(view) < 1) return;
if (getOrientation(parent) == LinearLayoutManager.VERTICAL)
outRect.top = divider.getIntrinsicHeight();
else
throw new IllegalArgumentException("Only usable with vertical lists");
}
@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
if (divider == null) {
super.onDrawOver(c, parent, state);
return;
}
final int left = parent.getPaddingLeft();
final int right = parent.getWidth() - parent.getPaddingRight();
final int childCount = parent.getChildCount();
for (int i = 0; i < childCount; ++i) {
final View child = parent.getChildAt(i);
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
final int size = divider.getIntrinsicHeight();
final int top = (int) (child.getTop() - params.topMargin - size + child.getTranslationY());
final int bottom = top + size;
divider.setBounds(left, top, right, bottom);
divider.draw(c);
if (i == childCount - 1) {
final int newTop = (int) (child.getBottom() + params.bottomMargin + child.getTranslationY());
final int newBottom = newTop + size;
divider.setBounds(left, newTop, right, newBottom);
divider.draw(c);
}
}
}
private int getOrientation(RecyclerView parent) {
if (!(parent.getLayoutManager() instanceof LinearLayoutManager))
throw new IllegalStateException("Layout manager must be an instance of LinearLayoutManager");
return ((LinearLayoutManager) parent.getLayoutManager()).getOrientation();
}
}
2）将装饰器添加到RecylerView：
recyclerView.addItemDecoration(new DividerItemDecoration(getActivity()));
答案 16 :(得分：6)
我如何处理Divider视图以及Divider插图的方法是添加RecyclerView扩展。
1。
通过命名View或RecyclerView添加新的扩展文件：
RecyclerViewExtension.kt
并在RecyclerViewExtension.kt文件中添加setDivider扩展方法。
/*
* RecyclerViewExtension.kt
* */
import androidx.annotation.DrawableRes
import androidx.core.content.ContextCompat
import androidx.recyclerview.widget.DividerItemDecoration
import androidx.recyclerview.widget.RecyclerView
fun RecyclerView.setDivider(@DrawableRes drawableRes: Int) {
val divider = DividerItemDecoration(
this.context,
DividerItemDecoration.VERTICAL
)
val drawable = ContextCompat.getDrawable(
this.context,
drawableRes
)
drawable?.let {
divider.setDrawable(it)
addItemDecoration(divider)
}
}
2。
在drawable包内创建一个Drawable资源文件，例如recycler_view_divider.xml：
<inset xmlns:android="http://schemas.android.com/apk/res/android"
android:insetLeft="10dp"
android:insetRight="10dp">
<shape>
<size android:height="0.5dp" />
<solid android:color="@android:color/darker_gray" />
</shape>
</inset>
您可以在android:insetLeft和android:insetRight上指定左边距。
3。
在初始化RecyclerView的Activity或Fragment上，您可以通过调用以下命令来设置自定义可绘制对象：
recyclerView.setDivider(R.drawable.recycler_view_divider)
4。
干杯?
答案 17 :(得分：6)
我们可以使用附加到recyclerview的各种装饰器来装饰物品，例如DividerItemDecoration：
只需使用以下内容......取自EyesClear
的答案public class DividerItemDecoration extends RecyclerView.ItemDecoration {
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
private Drawable mDivider;
/**
* Default divider will be used
*/
public DividerItemDecoration(Context context) {
final TypedArray styledAttributes = context.obtainStyledAttributes(ATTRS);
mDivider = styledAttributes.getDrawable(0);
styledAttributes.recycle();
}
/**
* Custom divider will be used
*/
public DividerItemDecoration(Context context, int resId) {
mDivider = ContextCompat.getDrawable(context, resId);
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
int left = parent.getPaddingLeft();
int right = parent.getWidth() - parent.getPaddingRight();
int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = parent.getChildAt(i);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
int top = child.getBottom() + params.bottomMargin;
int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
} 然后使用以上内容
RecyclerView.ItemDecoration itemDecoration = new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST);
recyclerView.addItemDecoration(itemDecoration);
这将在列表中的每个项目之间显示分隔符，如下所示：
对于那些正在寻找更多详细信息的人，可以查看本指南Using the RecyclerView _ CodePath Android Cliffnotes
这里的一些答案建议使用保证金，但问题是： 如果同时添加顶部和底部边距，它们将在项目之间添加，并且它们将太大。如果只添加其中一个，则整个列表的顶部或底部都没有边距。如果在顶部添加一半距离，在底部添加一半，则外边距将太小。
因此，唯一美学上正确的解决方案是系统知道正确应用位置的分隔线：项目之间但不高于或低于项目。
请在下面的评论中告诉我任何疑问：）
答案 18 :(得分：6)
从谷歌搜索中获取，将此ItemDecoration添加到您的RecyclerView：
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
private Drawable mDivider;
private boolean mShowFirstDivider = false;
private boolean mShowLastDivider = false;
public DividerItemDecoration(Context context, AttributeSet attrs) {
final TypedArray a = context
.obtainStyledAttributes(attrs, new int[]{android.R.attr.listDivider});
mDivider = a.getDrawable(0);
a.recycle();
}
public DividerItemDecoration(Context context, AttributeSet attrs, boolean showFirstDivider,
boolean showLastDivider) {
this(context, attrs);
mShowFirstDivider = showFirstDivider;
mShowLastDivider = showLastDivider;
}
public DividerItemDecoration(Drawable divider) {
mDivider = divider;
}
public DividerItemDecoration(Drawable divider, boolean showFirstDivider,
boolean showLastDivider) {
this(divider);
mShowFirstDivider = showFirstDivider;
mShowLastDivider = showLastDivider;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
if (mDivider == null) {
return;
}
if (parent.getChildPosition(view) < 1) {
return;
}
if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
outRect.top = mDivider.getIntrinsicHeight();
} else {
outRect.left = mDivider.getIntrinsicWidth();
}
}
@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
if (mDivider == null) {
super.onDrawOver(c, parent, state);
return;
}
// Initialization needed to avoid compiler warning
int left = 0, right = 0, top = 0, bottom = 0, size;
int orientation = getOrientation(parent);
int childCount = parent.getChildCount();
if (orientation == LinearLayoutManager.VERTICAL) {
size = mDivider.getIntrinsicHeight();
left = parent.getPaddingLeft();
right = parent.getWidth() - parent.getPaddingRight();
} else { //horizontal
size = mDivider.getIntrinsicWidth();
top = parent.getPaddingTop();
bottom = parent.getHeight() - parent.getPaddingBottom();
}
for (int i = mShowFirstDivider ? 0 : 1; i < childCount; i++) {
View child = parent.getChildAt(i);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
if (orientation == LinearLayoutManager.VERTICAL) {
top = child.getTop() - params.topMargin;
bottom = top + size;
} else { //horizontal
left = child.getLeft() - params.leftMargin;
right = left + size;
}
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
// show last divider
if (mShowLastDivider && childCount > 0) {
View child = parent.getChildAt(childCount - 1);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
if (orientation == LinearLayoutManager.VERTICAL) {
top = child.getBottom() + params.bottomMargin;
bottom = top + size;
} else { // horizontal
left = child.getRight() + params.rightMargin;
right = left + size;
}
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
private int getOrientation(RecyclerView parent) {
if (parent.getLayoutManager() instanceof LinearLayoutManager) {
LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
return layoutManager.getOrientation();
} else {
throw new IllegalStateException(
"DividerItemDecoration can only be used with a LinearLayoutManager.");
}
}
}
答案 19 :(得分：6)
这个链接对我来说就像一个魅力：
https://gist.github.com/lapastillaroja/858caf1a82791b6c1a36
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.View;
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
private Drawable mDivider;
private boolean mShowFirstDivider = false;
private boolean mShowLastDivider = false;
public DividerItemDecoration(Context context, AttributeSet attrs) {
final TypedArray a = context
.obtainStyledAttributes(attrs, new int[]{android.R.attr.listDivider});
mDivider = a.getDrawable(0);
a.recycle();
}
public DividerItemDecoration(Context context, AttributeSet attrs, boolean showFirstDivider,
boolean showLastDivider) {
this(context, attrs);
mShowFirstDivider = showFirstDivider;
mShowLastDivider = showLastDivider;
}
public DividerItemDecoration(Drawable divider) {
mDivider = divider;
}
public DividerItemDecoration(Drawable divider, boolean showFirstDivider,
boolean showLastDivider) {
this(divider);
mShowFirstDivider = showFirstDivider;
mShowLastDivider = showLastDivider;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
if (mDivider == null) {
return;
}
if (parent.getChildPosition(view) < 1) {
return;
}
if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
outRect.top = mDivider.getIntrinsicHeight();
} else {
outRect.left = mDivider.getIntrinsicWidth();
}
}
@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
if (mDivider == null) {
super.onDrawOver(c, parent, state);
return;
}
// Initialization needed to avoid compiler warning
int left = 0, right = 0, top = 0, bottom = 0, size;
int orientation = getOrientation(parent);
int childCount = parent.getChildCount();
if (orientation == LinearLayoutManager.VERTICAL) {
size = mDivider.getIntrinsicHeight();
left = parent.getPaddingLeft();
right = parent.getWidth() - parent.getPaddingRight();
} else { //horizontal
size = mDivider.getIntrinsicWidth();
top = parent.getPaddingTop();
bottom = parent.getHeight() - parent.getPaddingBottom();
}
for (int i = mShowFirstDivider ? 0 : 1; i < childCount; i++) {
View child = parent.getChildAt(i);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
if (orientation == LinearLayoutManager.VERTICAL) {
top = child.getTop() - params.topMargin;
bottom = top + size;
} else { //horizontal
left = child.getLeft() - params.leftMargin;
right = left + size;
}
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
// show last divider
if (mShowLastDivider && childCount > 0) {
View child = parent.getChildAt(childCount - 1);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
if (orientation == LinearLayoutManager.VERTICAL) {
top = child.getBottom() + params.bottomMargin;
bottom = top + size;
} else { // horizontal
left = child.getRight() + params.rightMargin;
right = left + size;
}
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
private int getOrientation(RecyclerView parent) {
if (parent.getLayoutManager() instanceof LinearLayoutManager) {
LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
return layoutManager.getOrientation();
} else {
throw new IllegalStateException(
"DividerItemDecoration can only be used with a LinearLayoutManager.");
}
}
}
然后在你的活动中：
mCategoryRecyclerView.addItemDecoration(
new DividerItemDecoration(this, null));
如果你使用的是片段，那就是这个：
mCategoryRecyclerView.addItemDecoration(
new DividerItemDecoration(getActivity(), null));
答案 20 :(得分：4)
我觉得需要一个简单的，基于代码的，不使用XML的答案
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(), DividerItemDecoration.VERTICAL);
ShapeDrawable shapeDrawableForDivider = new ShapeDrawable(new RectShape());
int dividerThickness = // (int) (SomeOtherView.getHeight() * desiredPercent);
shapeDrawableForDivider.setIntrinsicHeight(dividerThickness);
shapeDrawableForDivider.setAlpha(0);
dividerItemDecoration.setDrawable(shapeDrawableForDivider);
recyclerView.addItemDecoration(dividerItemDecoration);
答案 21 :(得分：4)
代替创建Array
(
[0] => hello
[1] => world
[2] => First
[3] => Second
[4] => Third
)
来更改分隔线的高度和颜色。您可以像
shape xml答案 22 :(得分：4)
如果您想为商品添加相同的空间，最简单的方法是为RecycleView添加top + left padding，为卡片商品添加右+底边距。
<强> dimens.xml
<resources>
<dimen name="divider">1dp</dimen>
</resources>
<强> list_item.xml
<CardView
android:layout_marginBottom="@dimen/divider"
android:layout_marginRight="@dimen/divider">
...
</CardView>
<强> list.xml
<RecyclerView
android:paddingLeft="@dimen/divider"
android:paddingTop="@dimen/divider"
/>
答案 23 :(得分：4)
太晚但是对于GridLayoutManager我使用了这个：
public class GridSpacesItemDecoration : RecyclerView.ItemDecoration
{
private int space;
public GridSpacesItemDecoration(int space) {
this.space = space;
}
public override void GetItemOffsets(Android.Graphics.Rect outRect, View view, RecyclerView parent, RecyclerView.State state)
{
var position = parent.GetChildLayoutPosition(view);
/// Only for GridLayoutManager Layouts
var manager = parent.GetLayoutManager() as GridLayoutManager;
if (parent.GetChildLayoutPosition(view) < manager.SpanCount)
outRect.Top = space;
if (position % 2 != 0) {
outRect.Right = space;
}
outRect.Left = space;
outRect.Bottom = space;
}
}
这项工作适用于任何跨度计数。
奥利。
答案 24 :(得分：4)
您可以轻松地以编程方式添加。
如果您的布局管理器是Linearlayout，那么您可以使用：
DividerItemDecoration可以是RecyclerView.ItemDecoration 用作LinearLayoutManager项目之间的分隔符。它支持 HORIZONTAL和VERTICAL方向。
mDividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(),
mLayoutManager.getOrientation());
recyclerView.addItemDecoration(mDividerItemDecoration);
答案 25 :(得分：3)
1.通过一起使用cardview和Recycler视图 我们可以轻松添加分隔符等效果。 离。https://developer.android.com/training/material/lists-cards.html
2.其他方法是将视图作为分隔符添加到回收站视图的list_item_layout 。
<View
android:id="@+id/view1"
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="@color/colorAccent" />
答案 26 :(得分：3)
public class CommonItemSpaceDecoration extends RecyclerView.ItemDecoration {
private int mSpace = 0;
private boolean mVerticalOrientation = true;
public CommonItemSpaceDecoration(int space) {
this.mSpace = space;
}
public CommonItemSpaceDecoration(int space, boolean verticalOrientation) {
this.mSpace = space;
this.mVerticalOrientation = verticalOrientation;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
outRect.top = SizeUtils.dp2px(view.getContext(), mSpace);
if (mVerticalOrientation) {
if (parent.getChildAdapterPosition(view) == 0) {
outRect.set(0, SizeUtils.dp2px(view.getContext(), mSpace), 0, SizeUtils.dp2px(view.getContext(), mSpace));
} else {
outRect.set(0, 0, 0, SizeUtils.dp2px(view.getContext(), mSpace));
}
} else {
if (parent.getChildAdapterPosition(view) == 0) {
outRect.set(SizeUtils.dp2px(view.getContext(), mSpace), 0, 0, 0);
} else {
outRect.set(SizeUtils.dp2px(view.getContext(), mSpace), 0, SizeUtils.dp2px(view.getContext(), mSpace), 0);
}
}
}
}
这将在每个项目的顶部和底部（或左侧和右侧）添加空间。然后您可以将其设置为您的recyclerView。
recyclerView.addItemDecoration(new CommonItemSpaceDecoration(16));
<强> SizeUtils.java
public class SizeUtils {
public static int dp2px(Context context, float dpValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (dpValue * scale + 0.5f);
}
}
答案 27 :(得分：3)
我在列表项中添加了一行，如下所示
<View
android:id="@+id/divider"
android:layout_width="match_parent"
android:layout_height="1px"
android:background="@color/dividerColor"/>
1px将画出细线。
如果你想隐藏最后一行的分隔符，那么onBindViewHolder上的
divider.setVisiblity(View.GONE);代表最后一个列表。
答案 28 :(得分：2)
实施自己的RecyclerView.ItemDecoration
版本public class SpacingItemDecoration extends RecyclerView.ItemDecoration {
private int spacingPx;
private boolean addStartSpacing;
private boolean addEndSpacing;
public SpacingItemDecoration(int spacingPx) {
this(spacingPx, false, false);
}
public SpacingItemDecoration(int spacingPx, boolean addStartSpacing, boolean addEndSpacing) {
this.spacingPx = spacingPx;
this.addStartSpacing = addStartSpacing;
this.addEndSpacing = addEndSpacing;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
if (spacingPx <= 0) {
return;
}
if (addStartSpacing && parent.getChildLayoutPosition(view) < 1 || parent.getChildLayoutPosition(view) >= 1) {
if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
outRect.top = spacingPx;
} else {
outRect.left = spacingPx;
}
}
if (addEndSpacing && parent.getChildAdapterPosition(view) == getTotalItemCount(parent) - 1) {
if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
outRect.bottom = spacingPx;
} else {
outRect.right = spacingPx;
}
}
}
private int getTotalItemCount(RecyclerView parent) {
return parent.getAdapter().getItemCount();
}
private int getOrientation(RecyclerView parent) {
if (parent.getLayoutManager() instanceof LinearLayoutManager) {
return ((LinearLayoutManager) parent.getLayoutManager()).getOrientation();
} else {
throw new IllegalStateException("SpacingItemDecoration can only be used with a LinearLayoutManager.");
}
}
}
答案 29 :(得分：2)
RecyclerView与ListView略有不同。实际上，RecyclerView需要一个ListView类似的结构。例如，LinearLayout。 LinearLayout具有用于划分每个元素的参数。
在下面的代码中，我有一个RecyclerView CardView个LinearLayout个<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".ToDoList">
<!-- A RecyclerView with some commonly used attributes -->
<android.support.v7.widget.RecyclerView
android:id="@+id/todo_recycler_view"
android:scrollbars="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</RelativeLayout>
个对象，其中“填充”会在项目之间放置一些空格。让那个空间真的很小，你得到一条线。
这是recyclerview_layout.xml中的Recycler视图
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent"
**android:padding="@dimen/activity_vertical_margin"**>
<!-- A CardView that contains a TextView -->
<android.support.v7.widget.CardView
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/card_view"
android:layout_gravity="center"
android:layout_width="match_parent"
android:layout_height="100dp"
android:elevation="30dp"
card_view:cardElevation="3dp">
<TextView
android:id="@+id/info_text"
android:layout_width="match_parent"
android:layout_height="match_parent"
/>
</android.support.v7.widget.CardView>
</LinearLayout>
以下是每个项目的外观（并且它显示为由于围绕着所有内容的LinearLayout中的android：padding而分开）。在另一个文件中：cards_layout.xml
$("button").click(function () {
var base_url = $('#base_url').val();
var id = $(this).attr('value');
$('#foo').remove();
alert(id)
$.ajax({
url: base_url + 'Reports/view_extra',
type: 'POST',
data: {
id: id
},
success: function (data) {
$("<div id='foo'></div>").appendTo(".append").append(data);
$("#dialog-modal").dialog({
height: 200,
width: 790,
modal: true
});
$("#dialog-modal").css("display", "block");
$("#dialog-modal").show();
}
});
});
<td><?php echo isset($v->comments) ? substr(ucfirst($v->comments), 0,100)."... <button class='more' value='$v->fid'>See More</button>" : '-' ?></td>
答案 30 :(得分：2)
为了在RecylerView中完成项目之间的间隔，我们可以使用ItemDecorators：
addItemDecoration(object : RecyclerView.ItemDecoration() {
override fun getItemOffsets(
outRect: Rect,
view: View,
parent: RecyclerView,
state: RecyclerView.State,
) {
super.getItemOffsets(outRect, view, parent, state)
if (parent.getChildAdapterPosition(view) > 0) {
outRect.top = 8.dp // Change this value with anything you want. Remember that you need to convert integers to pixels if you are working with dps :)
}
}
})
考虑到我粘贴的代码，需要考虑以下几点：
-
您实际上不需要调用
super.getItemOffsets，但我选择了，因为我想扩展基类定义的行为。如果该库进行了更新，在后台进行了更多的逻辑处理，那么我们将错过它。 -
作为向
Rect添加顶部间距的替代方法，您还可以添加底部间距，但是与获取适配器的最后一项有关的逻辑更加复杂，因此这可能会更好 -
我使用了extension属性将简单的整数转换为dps：
8.dp。这样的事情可能会起作用：
val Int.dp: Int
get() = (this * Resources.getSystem().displayMetrics.density + 0.5f).toInt()
// Extension function works too, but invoking it would become something like 8.dp()
答案 31 :(得分：2)
一个非常简单的解决方案是使用RecyclerView-FlexibleDivider
添加依赖项：
compile 'com.yqritc:recyclerview-flexibledivider:1.4.0'
添加到您的recyclerview：
recyclerView.addItemDecoration(new HorizontalDividerItemDecoration.Builder(context).build());
你已经完成了！
答案 32 :(得分：1)
在Kotlin中，这是我的处理方式，默认大小为10dp的项之间的空间很简单：
class SimpleItemDecoration(context: Context, space: Int = 10) : RecyclerView.ItemDecoration() {
private val spaceInDp = ConvertUtil.dpToPx(context, space)
override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
outRect.left = spaceInDp
outRect.right = spaceInDp
outRect.bottom = spaceInDp
// Add top margin only for the first item to avoid double space between items
if (parent.getChildAdapterPosition(view) == 0) {
outRect.top = spaceInDp
}
}
}
这是dpToPx方法：
fun dpToPx(context: Context, dp: Int): Int {
return (dp * context.resources.displayMetrics.density).toInt()
}
答案 33 :(得分：1)
这是一种装饰，可让您设置项目之间的间距以及边缘上的间距。这适用于HORIZONTAL和VERTICAL版式。
class LinearSpacingDecoration(
@Px private val itemSpacing: Int,
@Px private val edgeSpacing: Int = 0
): RecyclerView.ItemDecoration() {
override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
val count = parent.adapter?.itemCount ?: 0
val position = parent.getChildAdapterPosition(view)
val leading = if (position == 0) edgeSpacing else itemSpacing
val trailing = if (position == count - 1) edgeSpacing else 0
outRect.run {
if ((parent.layoutManager as? LinearLayoutManager)?.orientation == LinearLayout.VERTICAL) {
top = leading
bottom = trailing
} else {
left = leading
right = trailing
}
}
}
}
用法：
recyclerView.addItemDecoration(LinearSpacingDecoration(itemSpacing = 10, edgeSpacing = 20))
答案 34 :(得分：1)
•PrimeAdapter
通过使用PrimeAdapter，在RecyclerView中处理除法器可能非常简单。它提供了多种功能，并提供了更大的灵活性来创建和管理分隔符。
您可以按以下方式创建适配器：（请参阅github中有关使用的完整文档）
val adapter = PrimeAdapter.with(recyclerView)
.setLayoutManager(LinearLayoutManager(activity))
.set()
.build(ActorAdapter::class.java)
创建适配器实例后，只需使用以下命令即可添加分隔符：
//----- default divider:
adapter.setDivider()
//----- divider with custom drawable:
adapter.setDivider(ContextCompat.getDrawable(context, R.drawable.divider))
//----- divider with custom color:
adapter.setDivider(Color.RED)
//----- divider with custom color and custom inset:
adapter.setDivider(Color.RED, insetLeft = 16, insetRight = 16)
//----- deactivate dividers:
adapter.setDivider(null)
答案 35 :(得分：1)
使用此课程在RecyclerView中设置分隔符。
public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {
private int spanCount;
private int spacing;
private boolean includeEdge;
public GridSpacingItemDecoration(int spanCount, int spacing, boolean includeEdge) {
this.spanCount = spanCount;
this.spacing = spacing;
this.includeEdge = includeEdge;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
int position = parent.getChildAdapterPosition(view); // item position
int column = position % spanCount; // item column
if (includeEdge) {
outRect.left = spacing - column * spacing / spanCount; // spacing - column * ((1f / spanCount) * spacing)
outRect.right = (column + 1) * spacing / spanCount; // (column + 1) * ((1f / spanCount) * spacing)
if (position < spanCount) { // top edge
outRect.top = spacing;
}
outRect.bottom = spacing; // item bottom
} else {
outRect.left = column * spacing / spanCount; // column * ((1f / spanCount) * spacing)
outRect.right = spacing - (column + 1) * spacing / spanCount; // spacing - (column + 1) * ((1f / spanCount) * spacing)
if (position >= spanCount) {
outRect.top = spacing; // item top
}
}
}
}
答案 36 :(得分：1)
public class VerticalItemDecoration extends RecyclerView.ItemDecoration {
private boolean verticalOrientation = true;
private int space = 10;
public VerticalItemDecoration(int value, boolean verticalOrientation) {
this.space = value;
this.verticalOrientation = verticalOrientation;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
RecyclerView.State state) {
//skip first item in the list
if (parent.getChildAdapterPosition(view) != 0) {
if (verticalOrientation) {
outRect.set(space, 0, 0, 0);
} else if (!verticalOrientation) {
outRect.set(0, space, 0, 0);
}
}
}
}
mCompletedShippingRecyclerView.addItemDecoration(new VerticalItemDecoration(20,false));
答案 37 :(得分：1)
我有一种在RecyclerView中添加分隔符的简单方法。使用自定义适配器修改回收器视图布局，然后与回收器视图项一起添加带有背景颜色的LinearLayout（这将是分隔器颜色）并添加1dp的高度（或根据您的要求）和宽度以匹配父级
以下是示例代码。
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="18dp">
<TextView
android:id="@+id/list_row_SNO"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight=".8"
android:layout_gravity="end"
android:text="44."
android:textAlignment="center"
android:textSize="24sp"
android:textColor="@color/colorBlack"
android:fontFamily="sans-serif-condensed" />
<TextView
android:id="@+id/list_row_Heading"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight=".2"
android:layout_gravity="start"
android:text="Student's application for leave and this what"
android:textAlignment="textStart"
android:textSize="24sp"
android:textColor="@color/colorBlack"
android:fontFamily="sans-serif-condensed" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="@color/colorHighlight">
</LinearLayout>
答案 38 :(得分：1)
RecyclerView没有为绘制列表分隔符提供简单的界面。但实际上它为我们提供了更灵活的方式 绘制分隔线的方法。我们使用RecyclerView.ItemDecoration 用分隔器或任何你想要的东西来装饰RecyclerView的瓷砖。这也是它被称为ItemDecoration的原因。
如Meterial Design Guidelines中所述：
分隔符位于图块的基线内。
因此，如果您想遵循材料设计指南，则不需要额外的空间来绘制分隔线。只需在瓷砖上绘制它们。但是，您有权做任何您想做的事情。所以我实现了一个让你能够设置插图以及在瓷砖下面绘制的功能。
public class InsetDivider extends RecyclerView.ItemDecoration {
public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
private Paint mPaint;
// in pixel
private int mDividerHeight;
// left inset for vertical list, top inset for horizontal list
private int mFirstInset;
// right inset for vertical list, bottom inset for horizontal list
private int mSecondInset;
private int mColor;
private int mOrientation;
// set it to true to draw divider on the tile, or false to draw beside the tile.
// if you set it to false and have inset at the same time, you may see the background of
// the parent of RecyclerView.
private boolean mOverlay;
private InsetDivider() {
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setStyle(Paint.Style.FILL);
}
public int getDividerHeight() {
return mDividerHeight;
}
public void setDividerHeight(int dividerHeight) {
this.mDividerHeight = dividerHeight;
}
public int getFirstInset() {
return mFirstInset;
}
public void setFirstInset(int firstInset) {
this.mFirstInset = firstInset;
}
public int getSecondInset() {
return mSecondInset;
}
public void setSecondInset(int secondInset) {
this.mSecondInset = secondInset;
}
public int getColor() {
return mColor;
}
public void setColor(int color) {
this.mColor = color;
mPaint.setColor(color);
}
public int getOrientation() {
return mOrientation;
}
public void setOrientation(int orientation) {
this.mOrientation = orientation;
}
public boolean getOverlay() {
return mOverlay;
}
public void setOverlay(boolean overlay) {
this.mOverlay = overlay;
}
@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
if (mOrientation == VERTICAL_LIST) {
drawVertical(c, parent);
} else {
drawHorizontal(c, parent);
}
}
protected void drawVertical(Canvas c, RecyclerView parent) {
final int left = parent.getPaddingLeft() + mFirstInset;
final int right = parent.getWidth() - parent.getPaddingRight() - mSecondInset;
final int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
if (parent.getChildAdapterPosition(child) == (parent.getAdapter().getItemCount() - 1)) {
continue;
}
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
final int bottom;
final int top;
if (mOverlay) {
bottom = child.getBottom() + params.bottomMargin + Math.round(ViewCompat.getTranslationY(child));
top = bottom - mDividerHeight;
} else {
top = child.getBottom() + params.bottomMargin + Math.round(ViewCompat.getTranslationY(child));
bottom = top + mDividerHeight;
}
c.drawRect(left, top, right, bottom, mPaint);
}
}
protected void drawHorizontal(Canvas c, RecyclerView parent) {
final int top = parent.getPaddingTop() + mFirstInset;
final int bottom = parent.getHeight() - parent.getPaddingBottom() - mSecondInset;
final int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
final View child = parent.getChildAt(i);
if (parent.getChildAdapterPosition(child) == (parent.getAdapter().getItemCount() - 1)) {
continue;
}
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
.getLayoutParams();
final int right;
final int left;
if (mOverlay) {
right = child.getRight() + params.rightMargin + Math.round(ViewCompat.getTranslationX(child));
left = right - mDividerHeight;
} else {
left = child.getRight() + params.rightMargin + Math.round(ViewCompat.getTranslationX(child));
right = left + mDividerHeight;
}
c.drawRect(left, top, right, bottom, mPaint);
}
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
if (mOverlay) {
super.getItemOffsets(outRect, view, parent, state);
return;
}
if (mOrientation == VERTICAL_LIST) {
outRect.set(0, 0, 0, mDividerHeight);
} else {
outRect.set(0, 0, mDividerHeight, 0);
}
}
/**
* Handy builder for creating {@link InsetDivider} instance.
*/
public static class Builder {
private Context mContext;
private int mDividerHeight;
private int mFirstInset;
private int mSecondInset;
private int mColor;
private int mOrientation;
private boolean mOverlay = true; // set default to true to follow Material Design Guidelines
public Builder(Context context) {
mContext = context;
}
public Builder dividerHeight(int dividerHeight) {
mDividerHeight = dividerHeight;
return this;
}
public Builder insets(int firstInset, int secondInset) {
mFirstInset = firstInset;
mSecondInset = secondInset;
return this;
}
public Builder color(@ColorInt int color) {
mColor = color;
return this;
}
public Builder orientation(int orientation) {
mOrientation = orientation;
return this;
}
public Builder overlay(boolean overlay) {
mOverlay = overlay;
return this;
}
public InsetDivider build() {
InsetDivider insetDivider = new InsetDivider();
if (mDividerHeight == 0) {
// Set default divider height to 1dp.
insetDivider.setDividerHeight(mContext.getResources().getDimensionPixelSize(R.dimen.divider_height));
} else if (mDividerHeight > 0) {
insetDivider.setDividerHeight(mDividerHeight);
} else {
throw new IllegalArgumentException("Divider's height can't be negative.");
}
insetDivider.setFirstInset(mFirstInset < 0 ? 0 : mFirstInset);
insetDivider.setSecondInset(mSecondInset < 0 ? 0 : mSecondInset);
if (mColor == 0) {
throw new IllegalArgumentException("Don't forget to set color");
} else {
insetDivider.setColor(mColor);
}
if (mOrientation != InsetDivider.HORIZONTAL_LIST && mOrientation != InsetDivider.VERTICAL_LIST) {
throw new IllegalArgumentException("Invalid orientation");
} else {
insetDivider.setOrientation(mOrientation);
}
insetDivider.setOverlay(mOverlay);
return insetDivider;
}
}
}
你可以像这样使用它：
ItemDecoration divider = new InsetDivider.Builder(this)
.orientation(InsetDivider.VERTICAL_LIST)
.dividerHeight(getResources().getDimensionPixelSize(R.dimen.divider_height))
.color(getResources().getColor(R.color.colorAccent))
.insets(getResources().getDimensionPixelSize(R.dimen.divider_inset), 0)
.overlay(true)
.build();
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.addItemDecoration(divider);
我还写了一个关于如何实现ItemDecoration以及如何使用它们的演示应用程序。您可以查看我的GitHub回购Dividers-For-RecyclerView。它有三种实现：
- UnderneathDivider
- OverlayDivider
- InsetDivider
答案 39 :(得分：0)
这就是我在Kotlin中进行列显示（网格）的方式
class ItemDecorationColumns(private val space: Int) : ItemDecoration() {
override fun getItemOffsets(
outRect: Rect,
view: View,
parent: RecyclerView,
state: RecyclerView.State
) {
val position = parent.getChildLayoutPosition(view)
val manager = parent.layoutManager as GridLayoutManager?
val spanCount = manager?.spanCount ?: 0
if (position < spanCount) {
outRect.top = space
}
if (position % 2 != 0) {
outRect.right = space
}
outRect.left = space
outRect.bottom = space
}
}
用法
rvAlbums.addItemDecoration(ItemDecorationColumns(resources.getDimensionPixelSize(R.dimen.space)))
答案 40 :(得分：0)
这是我的懒惰方法，但它有效： 将CardView包装在布局中并在父布局上设置填充/边距以模仿分隔符，并强制将正常分隔符置为空
<强> list_item.xml
<LinearLayout
android:id="@+id/entry_item_layout_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingBottom="<divider_size>" > // this is the divider
<CardView
android:layout_width="<width_size>"
android:layout_height="<height_size>">
...
</CardView>
</LinearLayout
<强> list.xml
<RecyclerView
android:divider="@null"
android:layout_width="<width_size>"
android:layout_height="<height_size>"
...
/>
答案 41 :(得分：-2)
尝试一下：https://gist.github.com/shawnlinboy/3a1d8fd28fa690f22d3a35e7749ae010
ItemDecoration实现，该实现提供了在列表项之间添加额外空白的功能。
答案 42 :(得分：-3)
在初始化回收站视图对象后添加此行。
片段中的：
mRecyclerView.addItemDecoration(new DividerItemDecoration(getActivity(),android.R.drawable.divider_horizontal_bright));
mRecyclerView.addItemDecoration(new DividerItemDecoration(this,android.R.drawable.divider_horizontal_bright));
分隔物项目装饰
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
public static final int VERTICAL_LIST = 0;
public DividerItemDecoration(ListActivity listActivity, Object p1) {
}
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
private Drawable mDivider;
/**
* Default divider will be used
*/
public DividerItemDecoration(Context context) {
final TypedArray styledAttributes = context.obtainStyledAttributes(ATTRS);
mDivider = styledAttributes.getDrawable(0);
styledAttributes.recycle();
}
/**
* Custom divider will be used
*/
public DividerItemDecoration(Context context, int resId) {
mDivider = ContextCompat.getDrawable(context, resId);
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
int left = parent.getPaddingLeft();
int right = parent.getWidth() - parent.getPaddingRight();
int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = parent.getChildAt(i);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
int top = child.getBottom() + params.bottomMargin;
int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
}
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