RecyclerView没有显示兄弟视图的任何内容

Question

我昨天也发布了这个，但没有得到任何回应。没有人可以帮忙吗？基本上，当RecyclerView只是标签片段的视图时，它可以完美地工作。但是，一旦我想将其他视图作为此RecyclerView的兄弟包含（包含在一个线性布局中，而这是在NestedScrollView中依次包装），RecyclerView不会生成任何内容（或者现在显示？）。另一个视图显示了。所以任何想法我可能做错了什么？我没有将正确的视图/引用传递给适配器吗？

StocksCompleteListFragment.java

public class StocksCompleteListFragment extends Fragment {

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        NestedScrollView sv = (NestedScrollView) inflater.inflate(
                R.layout.fragment_stocks_completelist, container, false);
        LinearLayout mylinear = (LinearLayout) sv.findViewById(R.id.mainLinear);
        RecyclerView rv = (RecyclerView) mylinear.findViewById(R.id.recyclerview);
        if (rv == null){
            Toast.makeText(getActivity(),"Null", Toast.LENGTH_SHORT).show();
        }
        setupRecyclerView(rv);
        return sv;
    }

    private void setupRecyclerView(RecyclerView recyclerView) {
        recyclerView.setLayoutManager(new LinearLayoutManager(recyclerView.getContext()));
        recyclerView.setAdapter(new SimpleStringRecyclerViewAdapter(getActivity(),
                getRandomSublist(Cheeses.sCheeseStrings, 30)));
    }

    private List<String> getRandomSublist(String[] array, int amount) {
        ArrayList<String> list = new ArrayList<>(amount);
        Random random = new Random();
        while (list.size() < amount) {
            list.add(array[random.nextInt(array.length)]);
        }
        return list;
    }

    public static class SimpleStringRecyclerViewAdapter
            extends RecyclerView.Adapter<SimpleStringRecyclerViewAdapter.ViewHolder> {

        private final TypedValue mTypedValue = new TypedValue();
        private int mBackground;
        private List<String> mValues;

        public static class ViewHolder extends RecyclerView.ViewHolder {
            public String mBoundString;

            public final View mView;
            public final ImageView mImageView;
            public final TextView mTextView;

            public ViewHolder(View view) {
                super(view);
                mView = view;
                mImageView = (ImageView) view.findViewById(R.id.avatar);
                mTextView = (TextView) view.findViewById(android.R.id.text1);
            }

            @Override
            public String toString() {
                return super.toString() + " '" + mTextView.getText();
            }
        }

        public String getValueAt(int position) {
            return mValues.get(position);
        }

        public SimpleStringRecyclerViewAdapter(Context context, List<String> items) {
            context.getTheme().resolveAttribute(R.attr.selectableItemBackground, mTypedValue, true);
            mBackground = mTypedValue.resourceId;
            mValues = items;
        }

        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.list_item, parent, false);
            view.setBackgroundResource(mBackground);
            return new ViewHolder(view);
        }

        @Override
        public void onBindViewHolder(final ViewHolder holder, int position) {
            holder.mBoundString = mValues.get(position);
            holder.mTextView.setText(mValues.get(position));

            holder.mView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Context context = v.getContext();
                    Intent intent = new Intent(context, CheeseDetailActivity.class);
                    intent.putExtra(CheeseDetailActivity.EXTRA_NAME, holder.mBoundString);

                    context.startActivity(intent);
                }
            });

            Glide.with(holder.mImageView.getContext())
                    .load(Cheeses.getRandomCheeseDrawable())
                    .fitCenter()
                    .into(holder.mImageView);
        }

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

这是布局xml fragment_stocks_completelist.xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.NestedScrollView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <LinearLayout
        android:id="@+id/mainLinear"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <LinearLayout
            android:id="@+id/progressBarLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical"
            android:layout_marginBottom="4dp"
            android:layout_marginTop="8dp"
            android:background="@color/grayBackground"
            android:gravity="center_vertical|center_horizontal"
            android:padding="4dp"
            android:visibility="gone">

            <ProgressBar
                android:id="@+id/progressBar1"
                style="?android:attr/progressBarStyle"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />

        </LinearLayout>

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recyclerview"
            android:layout_width="match_parent"
            android:layout_height="match_parent" />

    </LinearLayout>

</android.support.v4.widget.NestedScrollView>

Answer 1

您应该使用自定义LayoutManager - 测量其子项（ LinearLayoutManager 或 GridLayoutManager ）：

public class CustomLayoutManager extends GridLayoutManager {
private static final String TAG = CustomLayoutManager.class.getCanonicalName();
// Number of columns to show in the grid
private static final int SPAN_COUNT = 2;

public CustomLayoutManager(final Context context) {
    super(context, SPAN_COUNT);
}

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

@Override
public void onMeasure(final RecyclerView.Recycler recycler, final RecyclerView.State state,
                      final int widthSpec, final 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, 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(final RecyclerView.Recycler recycler, final int widthSpec,
                               final int heightSpec, final int[] measuredDimension) {
    try {
        View view = recycler.getViewForPosition(0);

        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);
        }
    } catch (Exception e) {
        Log.e(TAG, e.getMessage());
    }
}}