Question

我从Android设备获取联系人。我的设备中有300个联系人。我在AsynckTask类的doInBackground（）方法中编写了联系提取过程。所以在取消进度对话框opPostExecute（）方法后，在android中的recyclerview中显示联系时间太长。请给我一些解决方案。

DatabaseAdapter类：

public class DatabaseAdapter {

EmsevaHelper帮手;

public DatabaseAdapter(Context context) {
    helper = new Helper(context);
}

public long insertRecord(String name, String number, String photo) {
    SQLiteDatabase db = helper.getWritableDatabase();
    ContentValues contentValues = new ContentValues();
    contentValues.put(Helper.CONTACT_NAME, name);
    contentValues.put(Helper.CONTACT_NUMBER, number);
    contentValues.put(Helper.CONTACT_PHOTO, photo);
    long id = 0;
    try {
        id = db.insertOrThrow(Helper.TABLE_NAME_CONTACT, null, contentValues);
    } catch (Exception e) {
        Log.e("InsertExce", String.valueOf(e));
    }

    return id;
}

public int getContactCount() {
    int count=0;
    SQLiteDatabase db;
    String countQuery = "SELECT * FROM " + Helper.TABLE_NAME_CONTACT;
    db = helper.getReadableDatabase();
    Cursor cursor = null;
    try {
        cursor = db.rawQuery(countQuery, null);
        count=cursor.getCount();
    } catch (Exception e) {
        e.printStackTrace();
    }
    finally {
       if(cursor!=null)
       {
           cursor.close();
       }
        if(db!=null && db.isOpen())
        {
            db.close();
        }
    }



    return count;
}

public ArrayList<ContactData> getAllRecord() {
    ArrayList<ContactData> contactData = new ArrayList<>();
    String selectQuery = "SELECT * FROM " + Helper.TABLE_NAME_CONTACT;
    SQLiteDatabase db = helper.getReadableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    if (cursor.moveToFirst()) {
        do {
            contactData.add(new ContactData(cursor.getString(0), cursor.getString(1), false, cursor.getString(2), cursor.getString(3)));
        } while (cursor.moveToNext());
    }
    cursor.close();
    return contactData;
}

static class Helper extends SQLiteOpenHelper {
    private Context context;

    private static final String DATABASE_NAME = "database";
    private static final String TABLE_NAME_CONTACT = "CONTACT";
    private static final int DATABASE_VERSION = 10;

    private static final String CID = "_id";
    private static final String CONTACT_NAME = "cname";
    private static final String CONTACT_NUMBER = "cnumber";
    private static final String CONTACT_PHOTO = "cphoto";

    private static final String CREATE_CONTACT_TABLE = "CREATE TABLE " + TABLE_NAME_CONTACT + "(" + CID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
            + CONTACT_NAME + " VARCHAR(100)," + CONTACT_NUMBER + " VARCHAR(50) UNIQUE ," + CONTACT_PHOTO + " VARCHAR(255));";

    private static final String DROP_CONTACT_TABLE = "DROP TABLE IF EXISTS " + TABLE_NAME_CONTACT;


    public Helper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
        this.context = context;

    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        //creating required table.
        try {
            db.execSQL(CREATE_CONTACT_TABLE);
            Log.e("TableCreate", "Susseccfully");
        } catch (SQLException e) {

            Log.e("onCreate Exce****", e + "");
        }

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        //on upgrade drop older tables.
        try {
            db.execSQL(DROP_CONTACT_TABLE);

            //create new tables.
            onCreate(db);
        } catch (SQLException e) {
            Log.e("onUpgrade Exce****", e + "");
        }


    }
}

}

片段上的AsynckTask：

  class ContactLoader extends AsyncTask<Void,Void,Void>{

    ProgressDialog pd;

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pd=ProgressDialog.show(getContext(),"Fetching Contact!","Please wait...",true,false);
    }


    @Override
    protected Void doInBackground(Void... params) {

        contactData=databaseAdapter.getAllRecord();
        contactAdapter.setContactAdapterData(contactData);
        return null;
    }


    @Override
    protected void onPostExecute(Void aVoid) {

        rvContactList.setAdapter(contactAdapter);
        super.onPostExecute(aVoid);
        pd.cancel();




    }
}

Answer 1

不要一次获取所有项目，而是使用scroll listener。基于滚动状态加载更多联系人。最初，您可以加载50个联系人，然后在向下滚动列表时加载。继续向联系人列表添加更多联系人并通知adapter。您可以执行以下操作，您可以在其中跟踪各种滚动状态：

listView.setOnScrollListener(new AbsListView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(AbsListView absListView, int scrollState) {

            if (scrollState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {

            }

            if (scrollState == AbsListView.OnScrollListener.SCROLL_STATE_IDLE) {

                }

            } else if (scrollState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {

                }
            } else {

            }
        }

        @Override
        public void onScroll(AbsListView absListView, int firstVisibleItem,
                             int visibleItemCount, int totalItemCount) {

        }
    });

recyclerview花了太长时间在android中显示300个联系人

1 个答案: