这是之前在ListView类中使用divider和dividerHeight参数实现的一个例子:
<ListView
android:id="@+id/activity_home_list_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:divider="@android:color/transparent"
android:dividerHeight="8dp"/>
然而，在RecyclerView类中我没有看到这样的可能性。
<android.support.v7.widget.RecyclerView
android:id="@+id/activity_home_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical"/>
在这种情况下，是否可以定义边距和/或直接添加自定义分隔符视图到列表项的布局中，或者是否有更好的方法来实现我的目标?
如果你想为物品添加相同的空间，最简单的方法是为RecycleView添加顶部+左侧填充，为卡片物品添加右侧+底部空白。
文件dimens.xml
<resources>
<dimen name="divider">1dp</dimen>
</resources>
文件list_item.xml
<CardView
android:layout_marginBottom="@dimen/divider"
android:layout_marginRight="@dimen/divider">
...
</CardView>
文件list.xml
<RecyclerView
...
android:paddingLeft="@dimen/divider"
android:paddingTop="@dimen/divider" />
而不是创建一个形状xml来改变分隔线的高度和颜色，你可以通过编程来创建它:
val divider = DividerItemDecoration(
context,
DividerItemDecoration.VERTICAL)
divider.setDrawable(ShapeDrawable().apply {
intrinsicHeight = resources.getDimensionPixelOffset(R.dimen.dp_15)
paint.color = Color.RED // Note:
// Currently (support version 28.0.0), we
// can not use tranparent color here. If
// we use transparent, we still see a
// small divider line. So if we want
// to display transparent space, we
// can set color = background color
// or we can create a custom ItemDecoration
// instead of DividerItemDecoration.
})
recycler_devices.addItemDecoration(divider)
使用这个类在你的RecyclerView中设置分隔符。
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
}
}
}
}
我觉得需要一个简单的、不使用XML的、基于代码的答案
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(), DividerItemDecoration.VERTICAL);
ShapeDrawable shapeDrawableForDivider = new ShapeDrawable(new RectShape());
int dividerThickness = // (int) (SomeOtherView.getHeight() * desiredPercent);
shapeDrawableForDivider.setIntrinsicHeight(dividerThickness);
shapeDrawableForDivider.setAlpha(0);
dividerItemDecoration.setDrawable(shapeDrawableForDivider);
recyclerView.addItemDecoration(dividerItemDecoration);
我非常喜欢这个答案，我用Kotlin的单一表达式重新写了一遍:
recyclerView.addItemDecoration(DividerItemDecoration(this,DividerItemDecoration.VERTICAL).also { deco ->
with (ShapeDrawable(RectShape())){
intrinsicHeight = (resources.displayMetrics.density * 24).toInt()
alpha = 0
deco.setDrawable(this)
}
})
这和@Nerdy最初的答案是一样的，只是它将分隔线的高度设置为24dp，而不是另一个视图高度的百分比。
