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
class VerticalGridSpacingDecoration(private val spacing: Int) : RecyclerView.ItemDecoration() {
override fun getItemOffsets(
outRect: Rect,
view: View,
parent: RecyclerView,
state: State
) {
val layoutManager = parent.layoutManager as? GridLayoutManager
if (layoutManager == null || layoutManager.orientation != VERTICAL) {
return super.getItemOffsets(outRect, view, parent, state)
}
val spanCount = layoutManager.spanCount
val position = parent.getChildAdapterPosition(view)
val column = position % spanCount
with(outRect) {
left = if (column == 0) 0 else spacing / 2
right = if (column == spanCount.dec()) 0 else spacing / 2
top = if (position < spanCount) 0 else spacing
}
}
}
其他回答
确保你在gradle模块中实现了这个:
implementation 'com.github.grzegorzojdana:SpacingItemDecoration:1.1.0'
创建这个简单的函数:
public static int dpToPx(Context c, int dp) {
Resources r = c.getResources();
return Math.round(TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, r.getDisplayMetrics()));
}
最后实现如下所示的空格:
photosRecycler.addItemDecoration(new SpacingItemDecoration(2, dpToPx(this, 4), true));
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:)
只有一个简单的解决方案,您可以记住并在任何需要的地方实施。没有bug,没有疯狂的计算。在卡片/物品布局中放置空白,并在RecyclerView中放置相同大小的填充:
item_layout.xml
<CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:margin="10dp">
activity_layout.xml
<RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp"/>
更新:
下面的代码将处理StaggeredGridLayoutManager、GridLayoutManager和LinearLayoutManager。
public class SpacesItemDecoration extends RecyclerView.ItemDecoration {
private int halfSpace;
public SpacesItemDecoration(int space) {
this.halfSpace = space / 2;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
if (parent.getPaddingLeft() != halfSpace) {
parent.setPadding(halfSpace, halfSpace, halfSpace, halfSpace);
parent.setClipToPadding(false);
}
outRect.top = halfSpace;
outRect.bottom = halfSpace;
outRect.left = halfSpace;
outRect.right = halfSpace;
}
}
然后使用它
mRecyclerView.addItemDecoration(new SpacesItemDecoration(mMargin));
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"/>
推荐文章
- BottomSheetDialogFragment的圆角
- 在应用程序启动时出现“无法获得BatchedBridge,请确保您的bundle被正确打包”的错误
- 我如何改变默认对话框按钮的文本颜色在安卓5
- 更改单选按钮的圆圈颜色
- 如何在android中复制一个文件?
- adb找不到我的设备/手机(MacOS X)
- 如何在新的材质主题中改变背面箭头的颜色?
- androidviewpager与底部点
- 相同的导航抽屉在不同的活动
- 如何从视图中获得托管活动?
- 单一的TextView与多种颜色的文本
- 如何在非活动类(LocationManager)中使用getSystemService ?
- 在清单中注册应用程序类?
- Android:从数组中编程创建旋转器
- Android命令行工具sdkmanager总是显示:警告:无法创建设置