我有一个应用程序来管理图书收藏(如播放列表)。

我想显示一个带有垂直 RecyclerView 的集合列表，并在每行内显示一个水平 RecyclerView 中的书籍列表。

当我将内部水平 RecyclerView 的 layout_height 设置为 300dp 时，它可以正确显示，但是 当我将它设置为 wrap_content 时，它什么也不显示。 我需要使用 wrap_content 因为我希望能够以编程方式更改布局管理器以在垂直和水平显示之间切换。

你知道我做错了什么吗？

我的 fragment 布局:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:background="@color/white">

    <com.twibit.ui.view.CustomSwipeToRefreshLayout
        android:id="@+id/swipe_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <android.support.v7.widget.RecyclerView
                android:id="@+id/shelf_collection_listview"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:paddingTop="10dp"/>

        </LinearLayout>

    </com.twibit.ui.view.CustomSwipeToRefreshLayout>
</LinearLayout>

集合元素布局:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="wrap_content"
              android:orientation="vertical">

    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:background="#FFF">

        <!-- Simple Header -->

    </RelativeLayout>

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:text="@string/empty_collection"
            android:id="@+id/empty_collection_tv"
            android:visibility="gone"
            android:gravity="center"/>

        <android.support.v7.widget.RecyclerView
            android:id="@+id/collection_book_listview"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"/> <!-- android:layout_height="300dp" -->

    </FrameLayout>

</LinearLayout>

书单项:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="180dp"
              android:layout_height="220dp"
              android:layout_gravity="center">

        <ImageView
            android:id="@+id/shelf_item_cover"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:maxWidth="150dp"
            android:maxHeight="200dp"
            android:src="@drawable/placeholder"
            android:contentDescription="@string/cover"
            android:adjustViewBounds="true"
            android:background="@android:drawable/dialog_holo_light_frame"/>

</FrameLayout>

这是我的收集适配器:

private class CollectionsListAdapter extends RecyclerView.Adapter<CollectionsListAdapter.ViewHolder> {
    private final String TAG = CollectionsListAdapter.class.getSimpleName();
    private Context mContext;

    // Create the ViewHolder class to keep references to your views
    class ViewHolder extends RecyclerView.ViewHolder {

        private final TextView mHeaderTitleTextView;
        private final TextView mHeaderCountTextView;

        private final RecyclerView mHorizontalListView;
        private final TextView mEmptyTextView;

        public ViewHolder(View view) {
            super(view);

            mHeaderTitleTextView = (TextView) view.findViewById(R.id.collection_header_tv);
            mHeaderCountTextView = (TextView) view.findViewById(R.id.collection_header_count_tv);

            mHorizontalListView = (RecyclerView) view.findViewById(R.id.collection_book_listview);
            mEmptyTextView = (TextView) view.findViewById(R.id.empty_collection_tv);
        }
    }


    public CollectionsListAdapter(Context context) {
        mContext = context;
    }


    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int i) {
        Log.d(TAG, "CollectionsListAdapter.onCreateViewHolder(" + parent.getId() + ", " + i + ")");
        // Create a new view by inflating the row item xml.
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.shelf_collection, parent, false);

        // Set the view to the ViewHolder
        ViewHolder holder = new ViewHolder(v);

        holder.mHorizontalListView.setHasFixedSize(false);
        holder.mHorizontalListView.setHorizontalScrollBarEnabled(true);

        // use a linear layout manager
        LinearLayoutManager mLayoutManager = new LinearLayoutManager(mContext);
        mLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
        holder.mHorizontalListView.setLayoutManager(mLayoutManager);

        return holder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int i) {
        Log.d(TAG, "CollectionsListAdapter.onBindViewHolder(" + holder.getPosition() + ", " + i + ")");

        Collection collection = mCollectionList.get(i);
        Log.d(TAG, "Collection : " + collection.getLabel());

        holder.mHeaderTitleTextView.setText(collection.getLabel());
        holder.mHeaderCountTextView.setText("" + collection.getBooks().size());

        // Create an adapter if none exists
        if (!mBookListAdapterMap.containsKey(collection.getCollectionId())) {
            mBookListAdapterMap.put(collection.getCollectionId(), new BookListAdapter(getActivity(), collection));
        }

        holder.mHorizontalListView.setAdapter(mBookListAdapterMap.get(collection.getCollectionId()));

    }

    @Override
    public int getItemCount() {
        return mCollectionList.size();
    }
}

最后是 Book 适配器:

private class BookListAdapter extends RecyclerView.Adapter<BookListAdapter.ViewHolder> implements View.OnClickListener {
    private final String TAG = BookListAdapter.class.getSimpleName();

    // Create the ViewHolder class to keep references to your views
    class ViewHolder extends RecyclerView.ViewHolder {
        public ImageView mCoverImageView;

        public ViewHolder(View view) {
            super(view);
            mCoverImageView = (ImageView) view.findViewById(R.id.shelf_item_cover);
        }
    }

    @Override
    public void onClick(View v) {
        BookListAdapter.ViewHolder holder = (BookListAdapter.ViewHolder) v.getTag();
        int position = holder.getPosition();
        final Book book = mCollection.getBooks().get(position);

        // Click on cover image
        if (v.getId() == holder.mCoverImageView.getId()) {
            downloadOrOpenBook(book);
            return;
        }
    }

    private void downloadOrOpenBook(final Book book) {
        // do stuff
    }

    private Context mContext;
    private Collection mCollection;

    public BookListAdapter(Context context, Collection collection) {
        Log.d(TAG, "BookListAdapter(" + context + ", " + collection + ")");
        mCollection = collection;
        mContext = context;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int i) {
        Log.d(TAG, "onCreateViewHolder(" + parent.getId() + ", " + i + ")");
        // Create a new view by inflating the row item xml.
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.shelf_grid_item, parent, false);

        // Set the view to the ViewHolder
        ViewHolder holder = new ViewHolder(v);
        holder.mCoverImageView.setOnClickListener(BookListAdapter.this); // Download or Open

        holder.mCoverImageView.setTag(holder);

        return holder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int i) {
        Log.d(TAG, "onBindViewHolder(" + holder.getPosition() + ", " + i + ")");

        Book book = mCollection.getBooks().get(i);

        ImageView imageView = holder.mCoverImageView;
        ImageLoader.getInstance().displayImage(book.getCoverUrl(), imageView);
    }

    @Override
    public int getItemCount() {
        return mCollection.getBooks().size();
    }
}

最佳答案

@user2302510 解决方案的效果不如您预期的那么好。方向和动态数据更改的完整解决方法是:

public class MyLinearLayoutManager extends LinearLayoutManager {

    public MyLinearLayoutManager(Context context, int orientation, boolean reverseLayout)    {
        super(context, orientation, reverseLayout);
    }

    private int[] mMeasuredDimension = new int[2];

    @Override
    public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                          int widthSpec, int heightSpec) {
        final int widthMode = View.MeasureSpec.getMode(widthSpec);
        final int heightMode = View.MeasureSpec.getMode(heightSpec);
        final int widthSize = View.MeasureSpec.getSize(widthSpec);
        final int heightSize = View.MeasureSpec.getSize(heightSpec);
        int width = 0;
        int height = 0;
        for (int i = 0; i < getItemCount(); i++) {
            measureScrapChild(recycler, i,
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    mMeasuredDimension);

            if (getOrientation() == HORIZONTAL) {
                width = width + mMeasuredDimension[0];
                if (i == 0) {
                    height = mMeasuredDimension[1];
                }
            } else {
                height = height + mMeasuredDimension[1];
                if (i == 0) {
                    width = mMeasuredDimension[0];
                }
            }
        }
        switch (widthMode) {
            case View.MeasureSpec.EXACTLY:
                width = widthSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        switch (heightMode) {
            case View.MeasureSpec.EXACTLY:
                height = heightSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        setMeasuredDimension(width, height);
    }

    private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                                   int heightSpec, int[] measuredDimension) {
        View view = recycler.getViewForPosition(position);
        if (view != null) {
            RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();
            int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                    getPaddingLeft() + getPaddingRight(), p.width);
            int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                    getPaddingTop() + getPaddingBottom(), p.height);
            view.measure(childWidthSpec, childHeightSpec);
            measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
            measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
            recycler.recycleView(view);
        }
    }
}

关于android - 嵌套回收器 View 高度不包含其内容，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/26649406/