【发布时间】：2015-10-16 09:44:08
【问题描述】：
我有一个垂直 RecyclerView 托管在 CoordinatorLayout 中，具有折叠工具栏布局。此 RecyclerView 的 ViewHolder 包含另一个带有 GridLayoutManager 的 RecyclerView。
这种嵌套的原因是内部 RecyclerView 显示的图片集合可以包含 1 到 20 张图片。我不知道会有多少张图片，但是Grid的span必须始终为3。每次绑定ViewHolder时，我都会调整RecyclerView的布局参数以适应内容。
如果没有 CollapsingToolBarLayout，这将非常有用。但是，如果有一个折叠工具栏，用我的手指在内部 RecyclerView 上滚动不会滚动折叠工具栏，但是在另一个项目上滚动。
再次强调，在绑定的 ViewHolder 中，如果我开始在嵌套的 RecyclerView 之外的任何其他项目上滚动，滚动工作正常。但是，如果我在嵌套的 RecyclerView 上开始滚动，它就会中断。
是否可以防止内部 RecyclerView 上的滚动拦截而只让 Parent 滚动？不过，我希望内部 RecyclerView 仍能处理点击次数。
这是该现象的 YouTube 链接：https://youtu.be/fzj7HmqskzU
这是父 RecyclerView 的 XML：
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivityFragment">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scrollbars="vertical"
app:layout_behavior="@string/appbar_scrolling_view_behavior" />
<android.support.design.widget.AppBarLayout
android:id="@+id/app_bar_layout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.design.widget.CollapsingToolbarLayout
android:id="@+id/collapsing_toolbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:elevation="4dp"
app:contentScrim="?attr/colorPrimary"
app:layout_collapseParallaxMultiplier="0.7"
app:layout_scrollFlags="scroll|exitUntilCollapsed">
<View
android:id="@+id/header_view"
android:layout_width="match_parent"
android:layout_height="192dp"
android:animateLayoutChanges="true"
android:background="@color/primary" />
<android.support.v7.widget.Toolbar
android:id="@+id/action_bar"
android:layout_width="match_parent"
android:layout_height="@dimen/abc_action_bar_default_height_material"
android:elevation="4dp"
app:layout_collapseMode="pin"
app:popupTheme="@style/Theme.AppCompat.NoActionBar"
app:theme="@style/Theme.AppCompat.NoActionBar" />
</android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>
这是托管嵌套 RecyclerView 的主 ViewHolder：
public class SimpleAdapter extends RecyclerView.Adapter<SimpleAdapter.ViewHolder> {
private static final int MODEL_OBJECT = 1;
private List<ModelObject> modelObjects;
private Context context;
private int imageSize;
public SimpleAdapter(List<ModelObject> modelObjects) {
this.modelObjects = modelObjects;
setHasStableIds(true);
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
context = viewGroup.getContext();
int screenWidth= context.getResources().getDisplayMetrics().widthPixels;
imageSize = screenWidth / 3;
final LayoutInflater inflater = LayoutInflater.from(context);
View itemView;
itemView = inflater.inflate(R.layout.fragment_main_row, viewGroup, false);
return new ViewHolder(itemView, viewType);
}
@Override
public void onBindViewHolder(ViewHolder viewHolder, final int position) {
final ModelObject modelObject = modelObjects.get(position);
// set text
modelObject.setPosition(position + 1);
viewHolder.titleTextView.setText(modelObject.getTitle());
viewHolder.positionTextView.setText("" + (position + 1));
adjustsizes(viewHolder.recyclerView, modelObject, imageSize);
final NestedAdapter nestedAdapter = new NestedAdapter(modelObject.getPhotos());
// Create and set GridLayoutManager for RecyclerView
final GridLayoutManager recylerViewGridLayoutManager = new GridLayoutManager(context, 3);
recylerViewGridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
return 1;
}
});
viewHolder.recyclerView.setAdapter(nestedAdapter);
viewHolder.recyclerView.setLayoutManager(recylerViewGridLayoutManager);
}
@Override
public int getItemViewType(int position) {
return MODEL_OBJECT;
}
@Override
public int getItemCount() {
return modelObjects.size();
}
@Override
public long getItemId(int position) {
return modelObjects.get(position).hashCode();
}
private void adjustsizes(RecyclerView recyclerView, ModelObject modelObject, int imageSize) {
LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) recyclerView.getLayoutParams();
if (modelObject.getPhotos() != null) {
Double numberOfRowsDouble = modelObject.getPhotos().size() / 3.0;
int numberOfRowsInt = (numberOfRowsDouble.intValue() < numberOfRowsDouble)
? numberOfRowsDouble.intValue() + 1
: numberOfRowsDouble.intValue();
params.height = imageSize * numberOfRowsInt;
}
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public int viewType;
public ViewGroup mContainer;
public View mDragHandle;
public TextView titleTextView;
public TextView positionTextView;
public RecyclerView recyclerView;
public ViewHolder(View itemView, int viewType) {
super(itemView);
this.viewType = viewType;
mContainer = (ViewGroup) itemView.findViewById(R.id.container);
mDragHandle = itemView.findViewById(R.id.drag_handle);
titleTextView = (TextView) itemView.findViewById(R.id.title);
positionTextView = (TextView) itemView.findViewById(R.id.position);
recyclerView = (RecyclerView) itemView.findViewById(R.id.recycler_view);
}
}
}
最后，这是带有图片的嵌套子对象的适配器：
public class NestedAdapter extends RecyclerView.Adapter<NestedAdapter.PhotoViewHolder> {
private static final int PHOTO = 1;
private Context context;
ArrayList<String> photos;
/**
* Default constructor, takes no data as nothing has been recieved from the API
*/
public NestedAdapter(ArrayList<String> photos) {
this.photos = photos;
}
@Override
public PhotoViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
this.context = viewGroup.getContext();
View itemView;
switch (viewType) {
default: // Load default Message layout as bucketLists all have the same layout
itemView = LayoutInflater.from(context).inflate(R.layout.fragment_photo_row, viewGroup, false);
break;
}
return new PhotoViewHolder(itemView, viewType);
}
@Override
public void onBindViewHolder(PhotoViewHolder viewHolder, final int position) {
// Switch depending on the kind of View
switch (getItemViewType(position)) {
case PHOTO: // Subtract 1, padding has taken up a space
final String photo = photos.get(position);
Picasso.with(context)
.load(photo)
.placeholder(R.drawable.rocks) // Must use place holder or fit won't work!
.fit()
.centerCrop()
.into(viewHolder.photo);
break;
}
}
@Override
public int getItemViewType(int position) {
return PHOTO;
}
@Override
public int getItemCount() {
return photos.size();
}
// ViewHolder for actual content
public final static class PhotoViewHolder extends RecyclerView.ViewHolder {
public int viewType; // Used to specify the view type.
public ImageView photo;
public PhotoViewHolder(View itemView, int ViewType) {
super(itemView);
switch (ViewType) {
case PHOTO:
viewType = PHOTO;
photo = (ImageView) itemView.findViewById(R.id.photo);
break;
}
}
}
}
【问题讨论】：
标签： android-recyclerview androiddesignsupport android-collapsingtoolbarlayout android-appbarlayout