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?
只需添加
recyclerView.addItemDecoration(new DividerItemDecoration(getContext(),
DividerItemDecoration.VERTICAL));
此外，您可能还需要添加依赖项
实现“com.android.support: recyclerview-v7:28.0.0”
为了自定义它，你可以添加一个自定义drawable:
DividerItemDecoration itemDecorator = new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL);
itemDecorator.setDrawable(ContextCompat.getDrawable(getContext(), R.drawable.divider));
你可以自由地使用任何自定义绘图，例如:
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<solid android:color="@color/colorPrimary"/>
<size android:height="0.5dp"/>
</shape>
从谷歌搜索，添加这个ItemDecoration到你的RecyclerView:
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
private Drawable mDivider;
private boolean mShowFirstDivider = false;
private boolean mShowLastDivider = false;
public DividerItemDecoration(Context context, AttributeSet attrs) {
final TypedArray a = context
.obtainStyledAttributes(attrs, new int[]{android.R.attr.listDivider});
mDivider = a.getDrawable(0);
a.recycle();
}
public DividerItemDecoration(Context context, AttributeSet attrs, boolean showFirstDivider,
boolean showLastDivider) {
this(context, attrs);
mShowFirstDivider = showFirstDivider;
mShowLastDivider = showLastDivider;
}
public DividerItemDecoration(Drawable divider) {
mDivider = divider;
}
public DividerItemDecoration(Drawable divider, boolean showFirstDivider,
boolean showLastDivider) {
this(divider);
mShowFirstDivider = showFirstDivider;
mShowLastDivider = showLastDivider;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
if (mDivider == null) {
return;
}
if (parent.getChildPosition(view) < 1) {
return;
}
if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
outRect.top = mDivider.getIntrinsicHeight();
} else {
outRect.left = mDivider.getIntrinsicWidth();
}
}
@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
if (mDivider == null) {
super.onDrawOver(c, parent, state);
return;
}
// Initialization needed to avoid compiler warning
int left = 0, right = 0, top = 0, bottom = 0, size;
int orientation = getOrientation(parent);
int childCount = parent.getChildCount();
if (orientation == LinearLayoutManager.VERTICAL) {
size = mDivider.getIntrinsicHeight();
left = parent.getPaddingLeft();
right = parent.getWidth() - parent.getPaddingRight();
} else { // Horizontal
size = mDivider.getIntrinsicWidth();
top = parent.getPaddingTop();
bottom = parent.getHeight() - parent.getPaddingBottom();
}
for (int i = mShowFirstDivider ? 0 : 1; i < childCount; i++) {
View child = parent.getChildAt(i);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
if (orientation == LinearLayoutManager.VERTICAL) {
top = child.getTop() - params.topMargin;
bottom = top + size;
} else { // Horizontal
left = child.getLeft() - params.leftMargin;
right = left + size;
}
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
// Show the last divider
if (mShowLastDivider && childCount > 0) {
View child = parent.getChildAt(childCount - 1);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
if (orientation == LinearLayoutManager.VERTICAL) {
top = child.getBottom() + params.bottomMargin;
bottom = top + size;
} else { // hHorizontal
left = child.getRight() + params.rightMargin;
right = left + size;
}
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
private int getOrientation(RecyclerView parent) {
if (parent.getLayoutManager() instanceof LinearLayoutManager) {
LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
return layoutManager.getOrientation();
} else {
throw new IllegalStateException(
"DividerItemDecoration can only be used with a LinearLayoutManager.");
}
}
}
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)
以下是我的偷懒方法，但它很有效:
将CardView包装在一个布局中，并在父布局上设置一个填充/边距来模拟分隔符，并强制将普通分隔符设置为null。
文件list_item.xml
<LinearLayout
android:id="@+id/entry_item_layout_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:paddingBottom="<divider_size>" > // This is the divider
<CardView
android:layout_width="<width_size>"
android:layout_height="<height_size>">
...
</CardView>
</LinearLayout
文件list.xml
<RecyclerView
android:divider="@null"
android:layout_width="<width_size>"
android:layout_height="<height_size>"
...
/>
