RecyclerView 中的网格项未正确显示

Question

由于某种原因，我的 RecyclerView 的内容（即来自 String 数组的字母）没有显示为例外。应该有 6 个字母出现，但只有 2 个出现。我已经为 RecyclerView 本身及其父级使用了android:layout_height="wrap_content"，但这仍然没有任何区别。

CardView XML 包含 RecyclerView（用于网格）

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:clickable="true"
    android:focusable="true"
    android:id="@+id/cardview_gv">

    <LinearLayout
        android:id="@+id/cardview_gv_main"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:padding="10dp"
        android:animateLayoutChanges="true">

        <LinearLayout
            android:id="@+id/cardview_gv_titlerow"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal"
            android:weightSum="100">

            <TextView
                android:id="@+id/tv_gv_title"
                android:layout_weight="90"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:textColor="?android:attr/textColorPrimary"
                style="@android:style/TextAppearance.Medium" />

            <TextView
                android:id="@+id/tv_gv_expandcollapse"
                android:clickable="true"
                android:focusable="true"
                android:layout_weight="10"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_marginStart="10dp" />
        </LinearLayout>

        <RelativeLayout
            android:id="@+id/relativelayout_gv"
            android:animateLayoutChanges="true"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <android.support.v7.widget.RecyclerView
                xmlns:android="http://schemas.android.com/apk/res/android"
                android:id="@+id/rv"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:nestedScrollingEnabled="false"
                android:overScrollMode="never"
                android:scrollbars="none" />
        </RelativeLayout>
    </LinearLayout>
</android.support.v7.widget.CardView>

Fragment中与RecyclerView相关的代码

                static final String[] frenchVowels = new String[]{
                    "a", "e", "i", "o", "u", "y"
                };

                RecyclerViewAdapter rvAdapterGL;
                final RecyclerView rvGL = viewHolder.itemView.findViewById(R.id.rv);
                int numberOfColumns = 2;
                rvGL.setLayoutManager(new GridLayoutManager(getActivity(), numberOfColumns));
                rvAdapterGL = new RecyclerViewAdapter(getActivity(), frenchVowels);
                rvGL.setAdapter(rvAdapterGL);

RecyclerView 适配器类

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> {

    private String[] mData;
    private LayoutInflater mInflater;

    // data is passed into the constructor
    public RecyclerViewAdapter(Context context, String[] data) {
        this.mInflater = LayoutInflater.from(context);
        this.mData = data;
    }

    // inflates the cell layout from xml when needed
    @Override
    @NonNull
    public RecyclerViewAdapter.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = mInflater.inflate(R.layout.gridview_item, parent, false);
        return new RecyclerViewAdapter.ViewHolder(view);
    }

    // binds the data to the TextView in each cell
    @Override
    public void onBindViewHolder(@NonNull RecyclerViewAdapter.ViewHolder holder, int position) {
        holder.myTextView.setText(mData[position]);
    }

    // total number of cells
    @Override
    public int getItemCount() {
        return mData.length;
    }


    // stores and recycles views as they are scrolled off screen
    public class ViewHolder extends RecyclerView.ViewHolder {
        TextView myTextView;

        ViewHolder(View itemView) {
            super(itemView);
            myTextView = itemView.findViewById(R.id.item_gridview);
        }
    }
}

gridview_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/item_gridview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:paddingStart="0dp"
        android:paddingEnd="10dp"
        android:paddingTop="10dp"
        android:paddingBottom="10dp"/>
</LinearLayout>

Answer 1

您必须将 recyclerview 项目的高度设置为 wrap_content，否则它会展开以占用所有可用空间（第 2 行及以后的行不在屏幕上）。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >

    <TextView
    android:id="@+id/item_gridview"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:paddingStart="0dp"
    android:paddingEnd="10dp"
    android:paddingTop="10dp"
    android:paddingBottom="10dp"/>
</LinearLayout>