如何使用GridLayoutManager与RecyclerView设置列间距? 在我的布局中设置空白/填充没有效果。
当前回答
这就是最后对我有用的方法:
binding.rows.addItemDecoration(object: RecyclerView.ItemDecoration() {
val px = resources.getDimensionPixelSize(R.dimen.grid_spacing)
val spanCount = 2
override fun getItemOffsets(outRect: Rect, view: View, parent: RecyclerView, state: RecyclerView.State) {
val index = parent.getChildLayoutPosition(view)
val isLeft = (index % spanCount == 0)
outRect.set(
if (isLeft) px else px/2,
0,
if (isLeft) px/2 else px,
px
)
}
})
因为我只有2列(val spanCount = 2),我可以只做isLeft。如果有> 2列,那么我也需要一个isMiddle,两边的值都是px/2。
我希望有一种方法来获得应用程序:spanCount从直接从RecyclerView,但我不相信有。
其他回答
如果你想在所有设备中固定你的RecyclerView项的大小。你可以这样做
public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {
private int mSpanCount;
private float mItemSize;
public GridSpacingItemDecoration(int spanCount, int itemSize) {
this.mSpanCount = spanCount;
mItemSize = itemSize;
}
@Override
public void getItemOffsets(final Rect outRect, final View view, RecyclerView parent,
RecyclerView.State state) {
final int position = parent.getChildLayoutPosition(view);
final int column = position % mSpanCount;
final int parentWidth = parent.getWidth();
int spacing = (int) (parentWidth - (mItemSize * mSpanCount)) / (mSpanCount + 1);
outRect.left = spacing - column * spacing / mSpanCount;
outRect.right = (column + 1) * spacing / mSpanCount;
if (position < mSpanCount) {
outRect.top = spacing;
}
outRect.bottom = spacing;
}
}
recyclerview_item.xml
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="@dimen/recycler_view_item_width"
...
>
...
</LinearLayout>
dimens.xml
<dimen name="recycler_view_item_width">60dp</dimen>
活动
int numberOfColumns = 3;
mRecyclerView.setLayoutManager(new GridLayoutManager(this, numberOfColumns));
mRecyclerView.setAdapter(...);
mRecyclerView.addItemDecoration(new GridSpacingItemDecoration(3,
getResources().getDimensionPixelSize(R.dimen.recycler_view_item_width)));
对于那些有问题的staggeredLayoutManager(如https://imgur.com/XVutH5u)
recyclerView的方法:
getChildAdapterPosition(view)
getChildLayoutPosition(view)
有时返回-1作为索引,所以我们可能会遇到设置itemDecor的麻烦。我的解决方案是覆盖已弃用的ItemDecoration的方法:
public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent)
而不是新手:
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, State state)
是这样的:
recyclerView.addItemDecoration(new RecyclerView.ItemDecoration() {
@Override
public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
TheAdapter.VH vh = (TheAdapter.VH) recyclerView.findViewHolderForAdapterPosition(itemPosition);
View itemView = vh.itemView; //itemView is the base view of viewHolder
//or instead of the 2 lines above maybe it's possible to use View itemView = layoutManager.findViewByPosition(itemPosition) ... NOT TESTED
StaggeredGridLayoutManager.LayoutParams itemLayoutParams = (StaggeredGridLayoutManager.LayoutParams) itemView.getLayoutParams();
int spanIndex = itemLayoutParams.getSpanIndex();
if (spanIndex == 0)
...
else
...
}
});
到目前为止似乎对我有用:)
如果你使用Header和GridLayoutManager,使用以下代码在Kotlin中编写的网格间距:
inner class SpacesItemDecoration(itemSpace: Int) : RecyclerView.ItemDecoration() {
var space: Int = itemSpace
override fun getItemOffsets(outRect: Rect?, view: View?, parent: RecyclerView?, state: RecyclerView.State?) {
super.getItemOffsets(outRect, view, parent, state)
val position = parent!!.getChildAdapterPosition(view)
val viewType = parent.adapter.getItemViewType(position)
// Check to not to set any margin to header item
if (viewType == GridViewAdapter.TYPE_HEADER) {
outRect!!.top = 0
outRect.left = 0
outRect.right = 0
outRect.bottom = 0
} else {
outRect!!.left = space
outRect.right = space
outRect.bottom = space
if (parent.getChildLayoutPosition(view) == 0) {
outRect.top = space
} else {
outRect.top = 0
}
}
}
}
并将ItemDecoration传递给RecyclerView为:
gridView.addItemDecoration(SpacesItemDecoration(10))
复制@edwardaa提供的代码,我使它完美地支持RTL:
public class GridSpacingItemDecoration extends RecyclerView.ItemDecoration {
private int spanCount;
private int spacing;
private boolean includeEdge;
private int headerNum;
private boolean isRtl = TextUtilsCompat.getLayoutDirectionFromLocale(Locale.getDefault()) == ViewCompat.LAYOUT_DIRECTION_RTL;
public GridSpacingItemDecoration(int spanCount, int spacing, boolean includeEdge, int headerNum) {
this.spanCount = spanCount;
this.spacing = spacing;
this.includeEdge = includeEdge;
this.headerNum = headerNum;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
int position = parent.getChildAdapterPosition(view) - headerNum; // item position
if (position >= 0) {
int column = position % spanCount; // item column
if(isRtl) {
column = spanCount - 1 - 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
}
}
} else {
outRect.left = 0;
outRect.right = 0;
outRect.top = 0;
outRect.bottom = 0;
}
}
}
对我来说,完美的解决方案是设置RecyclerView的宽度它的layoutmanager为GridLayoutManager为wrap_content
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