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?
实现它自己的RecyclerView版本。ItemDecoration
public class SpacingItemDecoration extends RecyclerView.ItemDecoration {
private int spacingPx;
private boolean addStartSpacing;
private boolean addEndSpacing;
public SpacingItemDecoration(int spacingPx) {
this(spacingPx, false, false);
}
public SpacingItemDecoration(int spacingPx, boolean addStartSpacing, boolean addEndSpacing) {
this.spacingPx = spacingPx;
this.addStartSpacing = addStartSpacing;
this.addEndSpacing = addEndSpacing;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
if (spacingPx <= 0) {
return;
}
if (addStartSpacing && parent.getChildLayoutPosition(view) < 1 || parent.getChildLayoutPosition(view) >= 1) {
if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
outRect.top = spacingPx;
} else {
outRect.left = spacingPx;
}
}
if (addEndSpacing && parent.getChildAdapterPosition(view) == getTotalItemCount(parent) - 1) {
if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
outRect.bottom = spacingPx;
} else {
outRect.right = spacingPx;
}
}
}
private int getTotalItemCount(RecyclerView parent) {
return parent.getAdapter().getItemCount();
}
private int getOrientation(RecyclerView parent) {
if (parent.getLayoutManager() instanceof LinearLayoutManager) {
return ((LinearLayoutManager) parent.getLayoutManager()).getOrientation();
} else {
throw new IllegalStateException("SpacingItemDecoration can only be used with a LinearLayoutManager.");
}
}
}
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>
只需在回收器视图对象的init之后添加这一行。
在片段:
mRecyclerView.addItemDecoration(new DividerItemDecoration(getActivity(),android.R.drawable.divider_horizontal_bright));
在活动
mRecyclerView.addItemDecoration(new DividerItemDecoration(this,android.R.drawable.divider_horizontal_bright));
项目装饰
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
public static final int VERTICAL_LIST = 0;
public DividerItemDecoration(ListActivity listActivity, Object p1) {
}
private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
private Drawable mDivider;
/**
* Default divider will be used
*/
public DividerItemDecoration(Context context) {
final TypedArray styledAttributes = context.obtainStyledAttributes(ATTRS);
mDivider = styledAttributes.getDrawable(0);
styledAttributes.recycle();
}
/**
* Custom divider will be used
*/
public DividerItemDecoration(Context context, int resId) {
mDivider = ContextCompat.getDrawable(context, resId);
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
int left = parent.getPaddingLeft();
int right = parent.getWidth() - parent.getPaddingRight();
int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = parent.getChildAt(i);
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
int top = child.getBottom() + params.bottomMargin;
int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
}
请注意一下Alex Fu在GitHub上的这个文件:
链接
它是“直接从支持演示中提取”的diveritemdecoration .java示例文件。
在我的项目中导入这个文件后,我能够很好地获得分隔线,并将其作为项目装饰添加到回收器视图。
下面是我的onCreateView在我的片段中包含Recyclerview的样子:
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_recycler_view, container, false);
mRecyclerView = (RecyclerView) rootView.findViewById(R.id.my_recycler_view);
mRecyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL));
mRecyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(getActivity());
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
return rootView;
}
我确信可以做额外的造型,但这只是一个起点。:)
public class CommonItemSpaceDecoration extends RecyclerView.ItemDecoration {
private int mSpace = 0;
private boolean mVerticalOrientation = true;
public CommonItemSpaceDecoration(int space) {
this.mSpace = space;
}
public CommonItemSpaceDecoration(int space, boolean verticalOrientation) {
this.mSpace = space;
this.mVerticalOrientation = verticalOrientation;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
outRect.top = SizeUtils.dp2px(view.getContext(), mSpace);
if (mVerticalOrientation) {
if (parent.getChildAdapterPosition(view) == 0) {
outRect.set(0, SizeUtils.dp2px(view.getContext(), mSpace), 0, SizeUtils.dp2px(view.getContext(), mSpace));
} else {
outRect.set(0, 0, 0, SizeUtils.dp2px(view.getContext(), mSpace));
}
} else {
if (parent.getChildAdapterPosition(view) == 0) {
outRect.set(SizeUtils.dp2px(view.getContext(), mSpace), 0, 0, 0);
} else {
outRect.set(SizeUtils.dp2px(view.getContext(), mSpace), 0, SizeUtils.dp2px(view.getContext(), mSpace), 0);
}
}
}
}
这将增加每个项目的顶部和底部(或左右)的空间。然后你可以将它设置为你的recyclerView。
recyclerView.addItemDecoration(new CommonItemSpaceDecoration(16));
文件SizeUtils.java
public class SizeUtils {
public static int dp2px(Context context, float dpValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (dpValue * scale + 0.5f);
}
}
public class VerticalItemDecoration extends RecyclerView.ItemDecoration {
private boolean verticalOrientation = true;
private int space = 10;
public VerticalItemDecoration(int value, boolean verticalOrientation) {
this.space = value;
this.verticalOrientation = verticalOrientation;
}
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent,
RecyclerView.State state) {
// Skip first item in the list
if (parent.getChildAdapterPosition(view) != 0) {
if (verticalOrientation) {
outRect.set(space, 0, 0, 0);
} else if (!verticalOrientation) {
outRect.set(0, space, 0, 0);
}
}
}
}
mCompletedShippingRecyclerView.addItemDecoration(new VerticalItemDecoration(20,false));