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
为了使https://stackoverflow.com/a/29905000/1649371(上面)解决方案工作,我必须修改以下方法(以及所有后续调用)
@SuppressWarnings("all")
protected int getItemSpanSize(RecyclerView parent, View view, int childIndex) {
RecyclerView.LayoutManager mgr = parent.getLayoutManager();
if (mgr instanceof GridLayoutManager) {
return ((GridLayoutManager) mgr).getSpanSizeLookup().getSpanSize(childIndex);
} else if (mgr instanceof StaggeredGridLayoutManager) {
return ((StaggeredGridLayoutManager.LayoutParams) view.getLayoutParams()).isFullSpan() ? spanCount : 1;
} else if (mgr instanceof LinearLayoutManager) {
return 1;
}
return -1;
}
@SuppressWarnings("all")
protected int getItemSpanIndex(RecyclerView parent, View view, int childIndex) {
RecyclerView.LayoutManager mgr = parent.getLayoutManager();
if (mgr instanceof GridLayoutManager) {
return ((GridLayoutManager) mgr).getSpanSizeLookup().getSpanIndex(childIndex, spanCount);
} else if (mgr instanceof StaggeredGridLayoutManager) {
return ((StaggeredGridLayoutManager.LayoutParams) view.getLayoutParams()).getSpanIndex();
} else if (mgr instanceof LinearLayoutManager) {
return 0;
}
return -1;
}
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));
RecyclerViews支持ItemDecoration的概念:围绕每个元素的特殊偏移和绘图。从这个答案中可以看出,你可以使用
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.getChildLayoutPosition(view) == 0) {
outRect.top = space;
} else {
outRect.top = 0;
}
}
}
然后通过
mRecyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view);
int spacingInPixels = getResources().getDimensionPixelSize(R.dimen.spacing);
mRecyclerView.addItemDecoration(new SpacesItemDecoration(spacingInPixels));
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
}
}
}
对于这个问题,有一个非常简单而灵活的解决方案,它只使用适用于每个LayoutManager的XML。
假设你想要一个相等的X间距(例如8dp)。
在另一个布局中包装CardView项 给外层布局填充X/2 (4dp) 使外层布局背景透明
...
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="200dp"
android:layout_height="200dp"
android:background="@android:color/transparent"
android:padding="4dip">
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v7.widget.CardView>
</LinearLayout>
给你的RecyclerView填充X/2 (4dp)
...
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="4dp" />
就是这样。你有完美的X (8dp)间距。
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