android - 如何将 ViewHolder 与我的 CursorAdapter 一起使用？

Question

我正在尝试将 viewHolder 与我的游标适配器一起使用，以显示来自 SQLITE 数据库的一些数据。

我搜索了一些解决方案，但我不明白如何在此示例中使用 de viewHolder。

有人可以帮我吗？这是我的代码:

public class MainActivity extends AppCompatActivity {
FilmDbAdapter mDbHelper;
Cursor FilmsCursor;
String[] arrayTitulo,arrayAno,arrayDirector;
Integer [] arrayPoster;


@Override
protected void onCreate (Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    setContentView(R.layout.list);//
    fillData();


}

public class CursorDemo extends CursorAdapter {

    public CursorDemo(Context context, Cursor c) {

        super(context, c , false);
        // TODO Auto-generated constructor stub
    }


    @Override
    public void bindView(View view, Context context, Cursor cursor) {
        // TODO Auto-generated method stub

        TextView title = (TextView) view.findViewById(R.id.txtViewTitulo);
        TextView dir = (TextView) view.findViewById(R.id.txtViewDirector);
        TextView anio = (TextView) view.findViewById(R.id.txtViewAno);
        ImageView img = (ImageView) view.findViewById(R.id.imgPoster);

        title.setText(cursor.getString(cursor.getColumnIndex("film")));
        dir.setText(cursor.getString(cursor.getColumnIndex("director")));
        anio.setText(cursor.getString(cursor.getColumnIndex("ano")));

        Context c = getApplicationContext();
        String nom = (cursor.getString(cursor.getColumnIndex("img")));
        int idimg = c.getResources().getIdentifier(nom,"mipmap" ,c.getPackageName());
        img.setImageResource(idimg);
    }

    @Override
    public void changeCursor(Cursor cursor) {
        // TODO Auto-generated method stub
        super.changeCursor(cursor);
    }

    @Override
    public View newView(Context context , Cursor cursor, ViewGroup viewGroup) {
        // TODO Auto-generated method stub
        LayoutInflater inflater = LayoutInflater.from(context);
        View view = inflater.inflate(R.layout.row, viewGroup ,false);

        return view;
    }

}


private void fillData (){

    mDbHelper = new FilmDbAdapter(this);
    mDbHelper.open();
    FilmsCursor = mDbHelper.fetchAll("hero");
    final CursorDemo cursorDemo = new CursorDemo(MainActivity.this, FilmsCursor);
    ListView lstViewPelis = (ListView) findViewById(R.id.lstViewPelis);
    lstViewPelis.setAdapter(cursorDemo);
}



public static class viewHolder {
    TextView Ano,Director;


    viewHolder(View row){
        this.Ano = (TextView) row.findViewById(R.id.txtViewAno);
        this.Director = (TextView) row.findViewById(R.id.txtViewDirector);
    }
}

Answer 1

CursorAdapter 不会在每次需要新行时调用 newView；如果它已经有一个View，它会调用bindView，所以创建的 View 实际上是重用的。以便根据您的要求更新这些方法

 @Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
    LayoutInflater inflater = LayoutInflater.from(context);
    View view = inflater.inflate(R.layout.row, viewGroup ,false);        

    viewHolder holder = new viewHolder(view);
    view.setTag(holder);

    return v;
}

@Override
public void bindView(View view, Context context, Cursor cursor) {
    // TODO Auto-generated method stub


    viewHolder holder = (viewHolder)view.getTag();

     holder.title.setText(cursor.getString(cursor.getColumnIndex("film")));
    //......follow all

    Context c = getApplicationContext();
    String nom = (cursor.getString(cursor.getColumnIndex("img")));
    int idimg = c.getResources().getIdentifier(nom,"mipmap" ,c.getPackageName());
    //...................
}