android recyclerview缺少的项目存在较大差距

recycleView.viewholder


public class historyRecycleholder extends recyclerview.viewholder{

公共文本查看历史记录单词;
公共约束布局词约束;

公共历史记录回收文件夹(查看项视图){
super(项目视图);
history word=itemview.findviewbyid(r.id.history\u word);
wordconstran=itemview.findviewbyid(r.id.history_recycler_constran);
}
}
历史回收商\u item.xml


<?xml version=“1.0”encoding=“utf-8”?gt;
<android.support.constraint.constraintlayout(限制布局)
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/历史记录\u回收器\u约束”
android:layout_width=“匹配父级”
android:layout_height=“wrap_content”>

<文本视图
android:id=“@+id/历史\u字”
android:layout_width=“0dp”
android:layout_height=“包装内容”
android:background=“@color/cardview_light_background”
安卓:paddingbottom=“5dp”
安卓:paddingend=“10dp”
android:paddingstart=“10dp”
安卓:paddingtop=“5dp”
安卓:textsize=“24sp”
安卓:textstyle=“bold”
app:layout_constraintBottom_tobottomof=“父级”
app:layout_constrainted_toendoff=“父级”
app:layout_constraintStart_toStartof=“父级”
app:layout_constraintop_totopof=“父级”
工具:text=“@string/word”/>
</android.support.constraint.constraintlayout>
来自活动


historyList=new arrayList<gt;();
HistoryAdapter=新的HistoryAdapter(HistoryList,this);

RecyclerView.LayoutManager布局管理器=
新建LinearLayoutManager(getApplicationContext());

recyclerview.setlayoutmanager(布局管理器);
recyclerView.setItemAnimator(new defaultItemAnimator());
RecyclerView.AdditemDecoration(新的DivideritemDecoration(this,
linearlayoutmanager.vertical));
recyclerview.setadapter(历史适配器);
recyclerview.sethasFixedSize(真);

viewGroup.layoutParams params=recyclerview.getlayoutParams();
params.height=(最大高度/2);
recyclerview.setlayoutParams(参数);
数据库数据通过AsyncLoader加载


@nullable
@覆盖
public arraylist<string>loadinbackground()。{

返回database.getwordsinSearchHistory();
}
数据库方法


public arraylist<string>getwordsinSearchHistory()。{
arraylist<string>list=new arraylist<>();

sqliteDatabase database=this.getreadabledatabase();

字符串查询=
“select*from”+搜索\历史记录\表
+“order by”+搜索\u历史记录\u表格\u列\u id+“desc”;

cursor cursor=database.rawquery(查询,空);
cursor.moveToFirst();
而(!)cursor.isafterlast()){
list.add(cursor.getString(cursor.getColumnIndex(search_history_table_column_word));
cursor.movetonext();
}
cursor.close();
退货清单;
}
video.




正如您所看到的,数据库中的tupperware一词不在recyclerview中。取而代之的是一个巨大的缺口。

从适配器

@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);
    }
}


历史记录回收器\u 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>


从活动中

        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;
    }