有效地加载回收站/列表视图项目

Question

我有一个应用程序可以在我的手机上从 sql database 加载项目，我所做的是我从 onResume() 方法加载项目，但查看事物并不是最有效的方式，我总是可以看到这些项目当我查看whatsApp 或contacts 等其他应用程序时正在加载，应用程序甚至看不到正在加载的项目。以我目前的加载方式，我的应用程序不仅速度慢，而且还进行了不必要的处理，有没有人知道我可以实现的更好更有效的方式？非常感谢您。

我的 Sql 数据库类概述：

public class Database  extends SQLiteOpenHelper {

//My list that holds my database items(which in my case is receipts)
private ArrayList<Receipt> allReceipts = new ArrayList<>();

  public ArrayList<Receipt> getAllReceipts() {
    try {
        allReceipts.clear();

        // Select All Query
        String selectQuery = "SELECT  * FROM " + Constants.RECEIPT_TABLE;

        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if(cursor != null)
        if (cursor.moveToFirst()) {
            do {

                Receipt receipt  = new Receipt();
                receipt.setId(Integer.parseInt(cursor.getString(0)));
                receipt.setMerchantName(cursor.getString(1));
                receipt.setPrice(cursor.getString(2));
                // Adding contact to list
                allReceipts.add(receipt);
            } while (cursor.moveToNext());
        }


        if(cursor != null)
        cursor.close();
        db.close();
        return allReceipts;
    } catch (Exception e) {
        // TODO: handle exception
        Log.e("all_receipts", "" + e);
    }

    return allReceipts;
}

收到收据的我的片段

 private void initRecycler()
 {
    Action<List<ParentListItem>> action = new Action<List<ParentListItem>>() {

        @NonNull
        @Override
        public String id() {
            // Return a unique ID.
            return "load all receipts";
        }
        @Nullable
        @Override
        protected List<ParentListItem> run() throws InterruptedException {
             receiptArrayList = database.getAllReceipts();
            return getReceipts();
        }

        @Override
        protected void done(@Nullable final List<ParentListItem> receipts) {
            progress.stop();

            assert receipts != null;
            if(receipts.isEmpty()) {



            }else {

                childAdapterListeners();



                adapter = new ReceiptExpandableAdapter(getContext(), receipts, onItemClickListenerCheckBtn, onItemClickListenerDeleteBtn, mOntemClickListenerViewBtn);
                recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
               // recyclerView.addItemDecoration(new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL_LIST));
                recyclerView.setAdapter(adapter);

            }
        }
    };
    action.execute();
  }



  @Override
public void onResume()
{
   initRecycler();
   super.onResume();

}

Answer 1

您是否尝试过扩展 CursorLoader？这是使用数据库数据填充列表的最有效和正确的方法。