我正在尝试使用RecyclerView在GridLayoutManager的最后一个元素行下添加间距。为此，我使用自定义ItemDecoration使用底部填充，其最后一个元素如下：
public class SpaceItemDecoration extends RecyclerView.ItemDecoration {
private int space;
private int bottomSpace = 0;
public SpaceItemDecoration(int space, int bottomSpace) {
this.space = space;
this.bottomSpace = bottomSpace;
}
public SpaceItemDecoration(int space) {
this.space = space;
this.bottomSpace = 0;
}
@Override
public void getItemOffsets(Rect outRect, View view,
RecyclerView parent, RecyclerView.State state) {
int childCount = parent.getChildCount();
final int itemPosition = parent.getChildAdapterPosition(view);
final int itemCount = state.getItemCount();
outRect.left = space;
outRect.right = space;
outRect.bottom = space;
outRect.top = space;
if (itemCount > 0 && itemPosition == itemCount - 1) {
outRect.bottom = bottomSpace;
}
}
}
但是这个方法的问题在于它搞砸了最后一行网格中的元素高度。我猜GridLayoutManager根据左边的间距改变元素的高度。实现这一目标的正确方法是什么？
这适用于LinearLayoutManager。如果GridLayoutManager有问题。
如果您在底部有一个FAB，并且需要在最后一行中滚动FAB以上的项目以便它们可见，那么它非常有用。
答案 0 :(得分：322)
只需添加填充并设置android:clipToPadding="false"
<RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="8dp"
android:clipToPadding="false" />
感谢这个精彩的answer！
答案 1 :(得分：9)
解决这个问题的方法是重写GridLayoutManager的SpanSizeLookup。
您必须对活动或片段中的GridlayoutManager进行更改，以便为RecylerView充气。
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//your code
recyclerView.addItemDecoration(new PhotoGridMarginDecoration(context));
// SPAN_COUNT is the number of columns in the Grid View
GridLayoutManager gridLayoutManager = new GridLayoutManager(context, SPAN_COUNT);
// With the help of this method you can set span for every type of view
gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
if (list.get(position).getType() == TYPE_HEADER) {
// Will consume the whole width
return gridLayoutManager.getSpanCount();
} else if (list.get(position).getType() == TYPE_CONTENT) {
// will consume only one part of the SPAN_COUNT
return 1;
} else if(list.get(position).getType() == TYPE_FOOTER) {
// Will consume the whole width
// Will take care of spaces to be left,
// if the number of views in a row is not equal to 4
return gridLayoutManager.getSpanCount();
}
return gridLayoutManager.getSpanCount();
}
});
recyclerView.setLayoutManager(gridLayoutManager);
}
答案 2 :(得分：6)
我有类似的问题，并在堆栈溢出时回复了另一个线程。为了帮助落入此页面的其他人，我将在此处重新发布。
阅读所有其他答复后，我发现recyclerview布局xml中的更改按预期可用于我的recycler视图：
android:paddingBottom="127px"
android:clipToPadding="false"
android:scrollbarStyle="outsideOverlay"
完整的布局如下：
<android.support.v7.widget.RecyclerView
android:id="@+id/library_list"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="160px"
android:layout_marginEnd="160px"
tools:listitem="@layout/library_list_item" />
有关之前和之后的效果，请参见androidblog.us上的链接：
Adding Space to End of Android Recylerview
让我知道它如何为您工作。
大卫
答案 3 :(得分：2)
您可以做的是在您的recyclerview中添加一个空页脚。你的填充将是你的页脚大小。
SELECT
table.[field1],
table.[Name],
Count(table.[Name]) AS [CountOfName]
FROM
table
GROUP BY
table.[field1],
table.[Name]
HAVING
(((table.[Name]) Like "*") AND ((Count(table.[Name]))>1));
答案 4 :(得分：1)
仅在最后一项的情况下，才应在“ Recycler View”中使用“装饰”作为底边距
recyclerView.addItemDecoration(MemberItemDecoration())
public class MemberItemDecoration extends RecyclerView.ItemDecoration {
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
// only for the last one
if (parent.getChildAdapterPosition(view) == parent.getAdapter().getItemCount() - 1) {
outRect.bottom = 50/* set your margin here */;
}
}
}
答案 5 :(得分：0)
对于这样的事情，建议使用ItemDecoration解决它们的意思。
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
<script type="text/javascript" src="http://maps.google.com/maps/api/js?libraries=geometry,places&sensor=true"></script>
<script>
function initialize() {
alert("ok");
var mapOptions = {
zoom: 14,
center: new google.maps.LatLng(24.4799425,73.0934957),
mapTypeId: google.maps.MapTypeId.ROADMAP
};
var map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);
var arr = new Array();
var polygons = [];
var bounds = new google.maps.LatLngBounds();
var coordinates = [];
var marker = new google.maps.Marker;
var getBounds;
// downloadUrl("subdivision-coordinates.php", function(data) {
//var xmlString = $('#xml_values').val();
var xmlString ="<subdivisions><subdivision name='Madivala'><coord lat='12.920496072962534' lng='77.6198673248291' id='6' /><coord lat='12.92409332232521' lng='77.62896537780762' id='6' /><coord lat='12.927439554274295' lng='77.6209831237793' id='6' /><coord lat='12.923340413955895' lng='77.61634826660156' id='6' /><coord lat='12.92066338803538' lng='77.61960983276367' id='6' /></subdivision><subdivision name='Sarjapur'><coord lat='12.91706608927013' lng='77.62372970581055' id='7' /><coord lat='12.9158948645401' lng='77.6389217376709' id='7' /><coord lat='12.919659495917085' lng='77.64299869537354' id='7' /><coord lat='12.92409332232521' lng='77.64793395996094' id='7' /><coord lat='12.92480440036714' lng='77.63424396514893' id='7' /><coord lat='12.920998017844783' lng='77.62089729309082' id='7' /></subdivision><subdivision name='Domulur'><coord lat='12.967758119178917' lng='77.63282775878906' id='8' /><coord lat='12.962237705403682' lng='77.65179634094238' id='8' /><coord lat='12.950025446093244' lng='77.64226913452148' id='8' /><coord lat='12.963826927981351' lng='77.6308536529541' id='8' /><coord lat='12.967507193936736' lng='77.63299942016602' id='8' /></subdivision><subdivision name='Indira Nagar'><coord lat='12.982227713276773' lng='77.63505935668945' id='9' /><coord lat='12.985154985380868' lng='77.64518737792969' id='9' /><coord lat='12.965834352522322' lng='77.64904975891113' id='9' /><coord lat='12.965834352522322' lng='77.63694763183594' id='9' /><coord lat='12.982060439543622' lng='77.63497352600098' id='9' /></subdivision><subdivision name='Mariyapan Palya'><coord lat='12.97846402705198' lng='77.54322052001953' id='10' /><coord lat='12.9792167688559' lng='77.56536483764648' id='10' /><coord lat='12.95671716919877' lng='77.56914138793945' id='10' /><coord lat='12.956298941771568' lng='77.54373550415039' id='10' /></subdivision></subdivisions>";
var xml = xmlParse(xmlString);
var subdivision = xml.getElementsByTagName("subdivision");
for (var i = 0; i < subdivision.length; i++) {
arr = [];
var coordinates = xml.documentElement.getElementsByTagName("subdivision")[i].getElementsByTagName("coord");
//console.log("coordinates="+xml.documentElement.getElementsByTagName("subdivision")[i].getElementsByTagName("coord"));
for (var j=0; j < coordinates.length; j++) {
arr.push(new google.maps.LatLng(
parseFloat(coordinates[j].getAttribute("lat")),
parseFloat(coordinates[j].getAttribute("lng"))
));
var idd=coordinates[j].getAttribute("id");
bounds.extend(arr[arr.length-1]);
}
polygons.push(new google.maps.Polygon({
id: idd,
paths: arr,
strokeColor: '#BA55D3',
strokeOpacity: 0.8,
strokeWeight: 2,
fillColor: '#DA70D6',
fillOpacity: 0.35
}));
polygons[polygons.length-1].setMap(map);
polygons[polygons.length-1].addListener('click', function (event) {
//alert(this.id);
var service_name=$('input[name="map_service"]:checked').val();
$('#add_to_qh').val(this.id);
$('#loc_edit_page').attr('href',"locality_service_edit.php?geoId="+this.id+"&service="+service_name);
$("#myModal").modal();
});
polygons[polygons.length-1].addListener('rightclick', function (event) {
console.log("Need to delete the clicked polygon");
});
}
map.fitBounds(bounds);
google.maps.event.addListener(map, 'idle', function() {
zoomLevel = map.getZoom();
center=map.getCenter();
var bounds1 = map.getBounds();
var min_lat = bounds1.getSouthWest().lat();
var min_lng = bounds1.getSouthWest().lng();
var max_lat = bounds1.getNorthEast().lat();
var max_lng = bounds1.getNorthEast().lng();
var nw = new google.maps.LatLng(min_lat, max_lng);
var se = new google.maps.LatLng(max_lat, min_lng);
var area22=google.maps.geometry.spherical.computeArea([bounds1.getNorthEast(),se, bounds1.getSouthWest(), nw]);
//Area chage meter2 to meter
area22 = area22/1000000;
var min_area = area22-((area22*20)/100);
var max_area = area22+((area22*20)/100);
$('#area').val(area22);
$('#min_area').val(min_area);
$('#max_area').val(max_area);
$('#min_lat').val(min_lat);
$('#max_lat').val(max_lat);
$('#min_lng').val(min_lng);
$('#max_lng').val(max_lng);
//console.log("Zoommmmmm my area="+area+" Min Area="+min_area+ " Max Area="+max_area);
});
}
/**
* Parses the given XML string and returns the parsed document in a
* DOM data structure. This function will return an empty DOM node if
* XML parsing is not supported in this browser.
* @param {string} str XML string.
* @return {Element|Document} DOM.
*/
function xmlParse(str) {
if (typeof ActiveXObject != 'undefined' && typeof GetObject != 'undefined') {
var doc = new ActiveXObject('Microsoft.XMLDOM');
doc.loadXML(str);
return doc;
}
if (typeof DOMParser != 'undefined') {
return (new DOMParser()).parseFromString(str, 'text/xml');
}
return createElement('div', null);
}
$(function(){
initialize();
});
</script>
<div id="map-canvas" style="height:620px;" ></div>
how to delete the particular polygon in google maps add event listener right click
我复制了原始答案here中的一个编辑，这实际上是等间距但是它是相同的概念。
答案 6 :(得分：0)
您可以从源代码中以DividerItemDecoration.java为例，并替换
for (int i = 0; i < childCount; i++)
使用
for (int i = 0; i < childCount - 1; i++)
在drawVertical（）和drawHorizontal（）
答案 7 :(得分：0)
看看可能的解决方案，我想写一些笔记和一个合适的解决方案：
如果您对 RecyclerView 使用填充，它应该在大多数情况下都可以工作，但是一旦您开始使用自定义的项目装饰（快速滚动条）或处理透明导航栏，您将看到各种问题。
您总是可以为 RecyclerView 适配器创建一个 ViewType，它将成为它的页脚，占据整个跨度。这很完美，但只需要比其他解决方案多做一点工作。
此处提供的 ItemDecoration 解决方案在大多数情况下都有效，但不适用于 GridLayoutManager，因为它有时会为最后一行上方的行添加间距（此处要求添加更好的解决方案）。
我在 android-x 上发现了一些似乎可以解决它的代码，不过，以某种方式与汽车有关：
BottomOffsetDecoration
/**
* A {@link RecyclerView.ItemDecoration} that will add a bottom offset to the last item in the
* RecyclerView it is added to.
*
* @hide
*/
@RestrictTo(LIBRARY_GROUP_PREFIX)
public class BottomOffsetDecoration extends RecyclerView.ItemDecoration {
private int mBottomOffset;
public BottomOffsetDecoration(int bottomOffset) {
mBottomOffset = bottomOffset;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
RecyclerView.Adapter adapter = parent.getAdapter();
if (adapter == null || adapter.getItemCount() == 0) {
return;
}
if (parent.getLayoutManager() instanceof GridLayoutManager) {
if (GridLayoutManagerUtils.isOnLastRow(view, parent)) {
outRect.bottom = mBottomOffset;
}
} else if (parent.getChildAdapterPosition(view) == adapter.getItemCount() - 1) {
// Only set the offset for the last item.
outRect.bottom = mBottomOffset;
} else {
outRect.bottom = 0;
}
}
/** Sets the value to use for the bottom offset. */
public void setBottomOffset(int bottomOffset) {
mBottomOffset = bottomOffset;
}
/** Returns the set bottom offset. If none has been set, then 0 will be returned. */
public int getBottomOffset() {
return mBottomOffset;
}
}
GridLayoutManagerUtils
/**
* Utility class that helps navigating in GridLayoutManager.
*
* <p>Assumes parameter {@code RecyclerView} uses {@link GridLayoutManager}.
*
* <p>Assumes the orientation of {@code GridLayoutManager} is vertical.
*
* @hide
*/
@RestrictTo(LIBRARY_GROUP_PREFIX)
public class GridLayoutManagerUtils {
private GridLayoutManagerUtils() {}
/**
* Returns the number of items in the first row of a RecyclerView that has a
* {@link GridLayoutManager} as its {@code LayoutManager}.
*
* @param recyclerView RecyclerView that uses GridLayoutManager as LayoutManager.
* @return number of items in the first row in {@code RecyclerView}.
*/
public static int getFirstRowItemCount(RecyclerView recyclerView) {
GridLayoutManager manager = (GridLayoutManager) recyclerView.getLayoutManager();
int itemCount = recyclerView.getAdapter().getItemCount();
int spanCount = manager.getSpanCount();
int spanSum = 0;
int numOfItems = 0;
while (numOfItems < itemCount && spanSum < spanCount) {
spanSum += manager.getSpanSizeLookup().getSpanSize(numOfItems);
numOfItems++;
}
return numOfItems;
}
/**
* Returns the span index of an item.
*/
public static int getSpanIndex(View item) {
GridLayoutManager.LayoutParams layoutParams =
((GridLayoutManager.LayoutParams) item.getLayoutParams());
return layoutParams.getSpanIndex();
}
/**
* Returns whether or not the given view is on the last row of a {@code RecyclerView} with a
* {@link GridLayoutManager}.
*
* @param view The view to inspect.
* @param parent {@link RecyclerView} that contains the given view.
* @return {@code true} if the given view is on the last row of the {@code RecyclerView}.
*/
public static boolean isOnLastRow(View view, RecyclerView parent) {
return getLastItemPositionOnSameRow(view, parent) == parent.getAdapter().getItemCount() - 1;
}
/**
* Returns the position of the last item that is on the same row as input {@code view}.
*
* @param view The view to inspect.
* @param parent {@link RecyclerView} that contains the given view.
*/
public static int getLastItemPositionOnSameRow(View view, RecyclerView parent) {
GridLayoutManager layoutManager = ((GridLayoutManager) parent.getLayoutManager());
GridLayoutManager.SpanSizeLookup spanSizeLookup = layoutManager.getSpanSizeLookup();
int spanCount = layoutManager.getSpanCount();
int lastItemPosition = parent.getAdapter().getItemCount() - 1;
int currentChildPosition = parent.getChildAdapterPosition(view);
int spanSum = getSpanIndex(view) + spanSizeLookup.getSpanSize(currentChildPosition);
// Iterate to the end of the row starting from the current child position.
while (currentChildPosition <= lastItemPosition && spanSum <= spanCount) {
spanSum += spanSizeLookup.getSpanSize(currentChildPosition + 1);
if (spanSum > spanCount) {
return currentChildPosition;
}
currentChildPosition++;
}
return lastItemPosition;
}
}
因此，我制作了一个 Kotlin 解决方案来解决所有问题（此处提供示例和库）：
//https://androidx.de/androidx/car/widget/itemdecorators/BottomOffsetDecoration.html
class BottomOffsetDecoration(private val mBottomOffset: Int, private val layoutManagerType: LayoutManagerType) : ItemDecoration() {
enum class LayoutManagerType {
GRID_LAYOUT_MANAGER, LINEAR_LAYOUT_MANAGER
}
override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
super.getItemOffsets(outRect, view, parent, state)
when (layoutManagerType) {
LayoutManagerType.LINEAR_LAYOUT_MANAGER -> {
val position = parent.getChildAdapterPosition(view)
outRect.bottom =
if (state.itemCount <= 0 || position != state.itemCount - 1)
0
else
mBottomOffset
}
LayoutManagerType.GRID_LAYOUT_MANAGER -> {
val adapter = parent.adapter
outRect.bottom =
if (adapter == null || adapter.itemCount == 0 || GridLayoutManagerUtils.isOnLastRow(view, parent))
0
else
mBottomOffset
}
}
}
}
//https://androidx.de/androidx/car/util/GridLayoutManagerUtils.html
/**
* Utility class that helps navigating in GridLayoutManager.
*
*
* Assumes parameter `RecyclerView` uses [GridLayoutManager].
*
*
* Assumes the orientation of `GridLayoutManager` is vertical.
*/
object GridLayoutManagerUtils {
/**
* Returns whether or not the given view is on the last row of a `RecyclerView` with a
* [GridLayoutManager].
*
* @param view The view to inspect.
* @param parent [RecyclerView] that contains the given view.
* @return `true` if the given view is on the last row of the `RecyclerView`.
*/
fun isOnLastRow(view: View, parent: RecyclerView): Boolean {
return getLastItemPositionOnSameRow(view, parent) == parent.adapter!!.itemCount - 1
}
/**
* Returns the position of the last item that is on the same row as input `view`.
*
* @param view The view to inspect.
* @param parent [RecyclerView] that contains the given view.
*/
private fun getLastItemPositionOnSameRow(view: View, parent: RecyclerView): Int {
val layoutManager = parent.layoutManager as GridLayoutManager
val spanSizeLookup = layoutManager.spanSizeLookup
val spanCount = layoutManager.spanCount
val lastItemPosition = parent.adapter!!.itemCount - 1
var currentChildPosition = parent.getChildAdapterPosition(view)
val itemSpanIndex = (view.layoutParams as GridLayoutManager.LayoutParams).spanIndex
var spanSum = itemSpanIndex + spanSizeLookup.getSpanSize(currentChildPosition)
// Iterate to the end of the row starting from the current child position.
while (currentChildPosition <= lastItemPosition && spanSum <= spanCount) {
spanSum += spanSizeLookup.getSpanSize(currentChildPosition + 1)
if (spanSum > spanCount)
return currentChildPosition
++currentChildPosition
}
return lastItemPosition
}
}