Question

我在listview中实现了无限的scrool。我已经实现了onScrollListner来实现它。这就是我的代码。

@Override
                public void onScroll(AbsListView view, int firstVisibleItem,
                        int visibleItemCount, int totalItemCount) {
                    // TODO Auto-generated method stub


                }

                @Override
                public void onScrollStateChanged(AbsListView view,
                        int scrollState) {
                    // TODO Auto-generated method stub



                         if (lv_connectionlist.getLastVisiblePosition() == lv_connectionlist.getAdapter().getCount() -1 &&
                                 lv_connectionlist.getChildAt(lv_connectionlist.getChildCount() - 1).getBottom() <= lv_connectionlist.getHeight())
                                {
                             if (scrollState == SCROLL_STATE_IDLE) {

                             Constants.page=String.valueOf((Integer.parseInt(Constants.page)+Integer.parseInt(Constants.count)));
                                    if(Integer.parseInt(totconn)>Integer.parseInt(Constants.page)){                 
                                        //myList = new ArrayList<ConnectionListData>();
                                        ConnectionListTask cnListtask = new ConnectionListTask();
                                        cnListtask.execute("");
                                        //lv_connectionlist.setSelection(Integer.parseInt(Constants.page.trim()));
                                        lv_connectionlist.smoothScrollToPosition(Integer.parseInt(Constants.page.trim()));
                                    }else{

                                        Constants.page=String.valueOf((Integer.parseInt(Constants.page)-Integer.parseInt(Constants.count)));
                                    }

                                }




                        }

                }

值Constants.page最初为零，我将它递增5.问题是每当我滚动我的列表视图，显示5个元素后，列表视图再次从顶部显示。它完美地绑定下一个5元素，但我想从最后一项显示它。任何帮助??

这是listview的适配器。

import java.util.ArrayList;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class ConnectionsListAdapters extends BaseAdapter{

    ArrayList<ConnectionListData> myList = new ArrayList<ConnectionListData>();
    LayoutInflater inflater;
    Context context;
    RelativeLayout.LayoutParams llps = null;
    ImageView ivArrow = null;
    BaseActivity mBaseAct = null;
    public ImageLoader imageLoader;


    public ConnectionsListAdapters(Context context, ArrayList<ConnectionListData> myList) {
        mBaseAct = new BaseActivity();
        this.myList = myList;
        this.context = context;
        imageLoader = new ImageLoader(this.context);
        inflater = LayoutInflater.from(this.context);   // only context can also be used
    }

    @Override
    public int getCount() {
        return myList.size();
    }

    @Override
    public ConnectionListData getItem(int position) {
        return myList.get(position);
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        MyViewHolder mViewHolder;

        if(convertView == null) {
            convertView = inflater.inflate(R.layout.connectionlist, null);
            mViewHolder = new MyViewHolder();
            convertView.setTag(mViewHolder);
        } else {
            mViewHolder = (MyViewHolder) convertView.getTag();
        }
        ((TextView) convertView.findViewById(R.id.favouritetext)).setTag(myList.get(position).getMemId());
        ((TextView) convertView.findViewById(R.id.connecttext)).setTag(myList.get(position).getMemId());

        mViewHolder.tvmemname=detail(convertView,R.id.tvmemname,myList.get(position).getname());
        mViewHolder.tvcompname=detail(convertView, R.id.tvcompname,myList.get(position).getcompanyname());
        mViewHolder.tvdescription=detail(convertView, R.id.tvdescription,myList.get(position).getdescription());
        mViewHolder.memimage=detail_file_name(convertView, R.id.memimage, myList.get(position).getmemimg());

        ImageView image = mViewHolder.memimage;

        imageLoader.DisplayImage(Constants.memimageurl+"/"+myList.get(position).getmemimg(),image);
        return convertView;
    }


    private TextView detail(View v, int resId, String text) {
        TextView tv = (TextView) v.findViewById(resId);
        tv.setText((text.length()>18)?(text.substring(0, 18)+"..."):text);
        return tv;
    }

    private ImageView detail_file_name(View v, int resId, String icon) {
        ImageView iv = (ImageView) v.findViewById(resId);
        //iv.setImageURI(uri); // 
        return iv;
    }

    private class MyViewHolder {
        TextView tvmemname = null; 
        TextView tvcompname = null;
        TextView tvdescription = null;
        ImageView memimage = null;
    }

}

Answer 1

得到解决方案：

cadapter=new ConnectionsListAdapters(context, myList);
        lv_connectionlist.setAdapter(cadapter);
          ((ConnectionsListAdapters)lv_connectionlist.getAdapter()).notifyDataSetChanged();
          lv_connectionlist.setSelection(Integer.parseInt(Constants.page.trim()));

在将适配器绑定到listview之后，我已经将setSelection方法放在 asyncTask 的onPostExecute()内。它就像魅力一样：）

Listview Onscroll显示listview顶部的第一个元素

1 个答案: