Android RecyclerView 缺少项目的大差距

Question

我有从 sqlite 数据库加载数据的回收器 View 。在打开 Activity 时，回收站 View 中没有加载任何内容，但在滚动时可以看到一半数据。再次转到顶部可以看到顶部项目，下面有很大的差距。缺口出现在缺失项目的位置。看这个video .

如您所见，数据库中的单词 tupperware 不在 recyclerview 中。取而代之的是一个很大的差距。

来自适配器

@NonNull
@Override
public HistoryRecycleHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {

    View view = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.history_recycler_item, parent, false);

    return new HistoryRecycleHolder(view);
}

@Override
public void onBindViewHolder(@NonNull HistoryRecycleHolder holder, int position) {

    final String txt = wordList.get(position);

    holder.historyWord.setText(txt);

    holder.wordConstrain.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent(context, WordActivity.class);
            intent.putExtra(IntentKeys.HISTORY_KEY, txt);
            context.startActivity(intent);
        }
    });

}

RecycleView.ViewHolder

public class HistoryRecycleHolder extends RecyclerView.ViewHolder {

    public TextView historyWord;
    public ConstraintLayout wordConstrain;

    public HistoryRecycleHolder(View itemView) {
        super(itemView);
        historyWord = itemView.findViewById(R.id.history_word);
        wordConstrain = itemView.findViewById(R.id.history_recycler_constrain);
    }
}

history_recycler_item.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    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:id="@+id/history_recycler_constrain"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

    <TextView
        android:id="@+id/history_word"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:background="@color/cardview_light_background"
        android:paddingBottom="5dp"
        android:paddingEnd="10dp"
        android:paddingStart="10dp"
        android:paddingTop="5dp"
        android:textSize="24sp"
        android:textStyle="bold"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:text="@string/word" />
</android.support.constraint.ConstraintLayout>

来自 Activity

        historyList = new ArrayList<>();
        historyAdapter = new HistoryAdapter(historyList, this);

        RecyclerView.LayoutManager layoutManager =
                new LinearLayoutManager(getApplicationContext());

        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.addItemDecoration(new DividerItemDecoration(this,
                LinearLayoutManager.VERTICAL));
        recyclerView.setAdapter(historyAdapter);
        recyclerView.setHasFixedSize(true);

        ViewGroup.LayoutParams params = recyclerView.getLayoutParams();
        params.height = (MaxHeight / 2);
        recyclerView.setLayoutParams(params);

数据库数据通过asyncLoader加载

@Nullable
@Override
public ArrayList<String> loadInBackground() {

        return database.getWordsInSearchHistory();
}

数据库方法

public ArrayList<String> getWordsInSearchHistory() {
        ArrayList<String> list = new ArrayList<>();

        SQLiteDatabase database = this.getReadableDatabase();

        String query =
                "SELECT * FROM " + SEARCH_HISTORY_TABLE
                        + " ORDER BY " + SEARCH_HISTORY_TABLE_COLUMN_ID + " DESC";

        Cursor cursor = database.rawQuery(query, null);
        cursor.moveToFirst();
        while (!cursor.isAfterLast()) {
            list.add(cursor.getString(cursor.getColumnIndex(SEARCH_HISTORY_TABLE_COLUMN_WORD)));
            cursor.moveToNext();
        }
        cursor.close();
        return list;
    }

Answer 1

唯一让我觉得奇怪的是，您以编程方式更改了回收 View 的布局参数。您能否尝试删除该部分并查看它是否有任何改变？