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
感谢edwardaa的回答https://stackoverflow.com/a/30701422/2227031
另一点需要注意的是:
如果total spacing和total itemWidth不等于屏幕宽度,您还需要调整itemWidth,例如,在适配器onBindViewHolder方法
Utils.init(_mActivity);
int width = 0;
if (includeEdge) {
width = ScreenUtils.getScreenWidth() - spacing * (spanCount + 1);
} else {
width = ScreenUtils.getScreenWidth() - spacing * (spanCount - 1);
}
int itemWidth = width / spanCount;
ConstraintLayout.LayoutParams layoutParams = (ConstraintLayout.LayoutParams) holder.imageViewAvatar.getLayoutParams();
// suppose the width and height are the same
layoutParams.width = itemWidth;
layoutParams.height = itemWidth;
holder.imageViewAvatar.setLayoutParams(layoutParams);
其他回答
如果你已经滚动到这个答案,我写了一个等间距库,支持垂直/水平,LTR/RTL,线性布局/GridLayout管理器和边缘包含。它基本上是一个文件,所以你可以复制粘贴该文件到你的代码中。
我试图支持StaggeredGridLayout,但这个布局返回的跨度索引不可靠。我很乐意听到任何有关这方面的建议。
如果你想要物品周围的间距和物品大小相等,下面是一步一步的简单解决方案。
ItemOffsetDecoration
public class ItemOffsetDecoration extends RecyclerView.ItemDecoration {
private int mItemOffset;
public ItemOffsetDecoration(int itemOffset) {
mItemOffset = itemOffset;
}
public ItemOffsetDecoration(@NonNull Context context, @DimenRes int itemOffsetId) {
this(context.getResources().getDimensionPixelSize(itemOffsetId));
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
outRect.set(mItemOffset, mItemOffset, mItemOffset, mItemOffset);
}
}
实现
在源代码中,将ItemOffsetDecoration添加到RecyclerView中。 项偏移值应该是实际值的一半大小,作为项之间的空间。
mRecyclerView.setLayoutManager(new GridLayoutManager(context, NUM_COLUMNS);
ItemOffsetDecoration itemDecoration = new ItemOffsetDecoration(context, R.dimen.item_offset);
mRecyclerView.addItemDecoration(itemDecoration);
同样,设置项目偏移值为itsRecyclerView的填充,并指定android:clipToPadding=false。
<android.support.v7.widget.RecyclerView
android:id="@+id/recyclerview_grid"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:clipToPadding="false"
android:padding="@dimen/item_offset"/>
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)));
如果你有一个在列表和网格之间切换的拨动开关,不要忘记在设置任何新的项目装饰之前调用recyclerView.removeItemDecoration(..)。如果不是这样,那么新的间隔计算将是不正确的。
就像这样:
recyclerView.removeItemDecoration(gridItemDecorator)
recyclerView.removeItemDecoration(listItemDecorator)
if (showAsList) {
recyclerView.layoutManager = LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false)
recyclerView.addItemDecoration(listItemDecorator)
} else {
recyclerView.layoutManager = GridLayoutManager(this, spanCount)
recyclerView.addItemDecoration(gridItemDecorator)
}
下面的代码工作得很好,每个列都有相同的宽度:
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
}
}
}
}
使用
1. 没有优势
int spanCount = 3; // 3 columns
int spacing = 50; // 50px
boolean includeEdge = false;
recyclerView.addItemDecoration(new GridSpacingItemDecoration(spanCount, spacing, includeEdge));
2. 与边缘
int spanCount = 3; // 3 columns
int spacing = 50; // 50px
boolean includeEdge = true;
recyclerView.addItemDecoration(new GridSpacingItemDecoration(spanCount, spacing, includeEdge));
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