android – ListView使我的应用程序运行速度很慢,虽然我创建了Holder Class

概述我对这个问题变得非常绝望,而且我一直在尝试你在其他线程中发布的所有想法. 问题是我的程序大量调用getView()方法,并且我实现了Holder范例,但它仍然非常慢,也许有人可以启发我？ 这是我的Adapter类： import java.util.ArrayList;import android.content.Context;import android.location.Locatio 我对这个问题变得非常绝望,而且我一直在尝试你在其他线程中发布的所有想法.

问题是我的程序大量调用getVIEw()方法,并且我实现了Holder范例,但它仍然非常慢,也许有人可以启发我？

这是我的Adapter类：

import java.util.ArrayList;import androID.content.Context;import androID.location.Location;import androID.vIEw.LayoutInflater;import androID.vIEw.VIEw;import androID.vIEw.VIEwGroup;import androID.Widget.ArrayAdapter;import androID.Widget.TextVIEw;    public class IconListVIEwAdapterPharmacy extends ArrayAdapter<PharmacyListItem>     {    private ArrayList<PharmacyListItem> items;    private Context cont;    private Location l;    public IconListVIEwAdapterPharmacy(Context cont,int textVIEwResourceID,ArrayList<PharmacyListItem> items,Location l)    {        super(cont,textVIEwResourceID,items);        this.cont = cont;        this.items = items;        this.l = l;    }    @OverrIDe    public VIEw getVIEw(int position,VIEw convertVIEw,VIEwGroup parent)     {        VIEw v = convertVIEw;        PharmacyListItem o = items.get(position);        VIEwHolder holder = new VIEwHolder();        if (v == null)         {            LayoutInflater vi = (LayoutInflater)cont.getSystemService(Context.LAYOUT_INFLATER_SERVICE);            v = vi.inflate(R.layout.icon_row_pharmacy,null);            holder.tt = (TextVIEw) v.findVIEwByID(R.ID.pharmacy_row_toptext);            holder.address = (TextVIEw) v.findVIEwByID(R.ID.pharmacy_row_address);            holder.distance = (TextVIEw) v.findVIEwByID(R.ID.pharmacy_row_distance);            holder.telephone = (TextVIEw) v.findVIEwByID(R.ID.pharmacy_row_telephone);         // associate the holder with the vIEw for later lookup            v.setTag(holder);        }            else        {            holder = (VIEwHolder)convertVIEw.getTag();        }        holder.tt.setText(o.getname());             String add = "" + o.getAddress();        holder.address.setText("" + add.substring(0,add.lastIndexOf(",")));        holder.telephone.setText("" + o.getTelephone());        String distancia = "" + o.getdistance();        if(l != null)        holder.distance.setText("distancia: " + distancia);        return v;    }        static class VIEwHolder         {            TextVIEw tt;            TextVIEw address;            TextVIEw distance;            TextVIEw telephone;        }    }

PharmacyListItem类：

import androID.location.Location;    public class PharmacyListItem     {    private String name;private double lat;private double lng;private String telephone;private double distance;public PharmacyListItem(Location l,String name,double lat,double lng,String telephone){    this.name = name;    this.lng = lng;    this.lat = lat;    this.telephone = telephone;    Location l2 = new Location(l);    l2.setLatitude(lat);    l2.setLongitude(lng);    distance = l.distanceto(l2);}public String getname(){    return name;}public String getAddress(){    return Geolocator.getAddress(lat,lng);}public String getTelephone(){    return telephone;}public String getdistance(){    return (""+distance).substring(0,(""+distance).indexOf(".")) + "m.";}public double getdist(){    return distance;}

}

任何想法将不胜感激！

谢谢你们！

编辑我粘贴我的.xml文件：

<?xml version="1.0" enCoding="utf-8"?><linearLayoutxmlns:androID="http://schemas.androID.com/apk/res/androID"androID:layout_wIDth="fill_parent"androID:layout_height="?androID:attr/ListPreferredItemHeight"androID:padding="6dip"androID:layout_marginRight="4dip"androID:background="@drawable/bg_detalle_1">       <ImageVIEw        androID:ID="@+ID/arrow2"         androID:layout_wIDth="wrap_content"        androID:layout_centerVertical="true"        androID:layout_height="wrap_content"         androID:layout_alignParentRight="true"        androID:layout_alignParentBottom="true"           androID:singleline="true"        androID:ellipsize="marquee"        androID:layout_marginRight="4dip"/>      <linearLayout androID:padding="10dip" androID:layout_wIDth="match_parent" androID:layout_height="wrap_content" androID:ID="@+ID/linearLayout3" androID:orIEntation="vertical">          <linearLayout androID:layout_height="wrap_content" androID:ID="@+ID/linearLayout1" androID:layout_wIDth="match_parent">              <TextVIEw androID:gravity="center" androID:textcolor="#525252" androID:layout_height="fill_parent" androID:singleline="true" androID:ellipsize="marquee" androID:text="" androID:textStyle="bold" androID:ID="@+ID/pharmacy_row_toptext" androID:layout_wIDth="wrap_content" androID:layout_marginRight="6dip"></TextVIEw>          </linearLayout>          <linearLayout androID:layout_height="wrap_content" androID:ID="@+ID/linearLayout2" androID:layout_wIDth="match_parent">                  <TextVIEw androID:layout_height="fill_parent" androID:text="TextVIEw" androID:ID="@+ID/pharmacy_row_address" androID:layout_wIDth="wrap_content" androID:layout_marginRight="6dip"></TextVIEw>          </linearLayout>          <linearLayout androID:layout_height="wrap_content" androID:layout_wIDth="match_parent" androID:ID="@+ID/linearLayout5">              <TextVIEw androID:gravity="center" androID:layout_height="fill_parent" androID:text="TextVIEw" androID:singleline="true" androID:ellipsize="marquee" androID:layout_wIDth="wrap_content" androID:ID="@+ID/pharmacy_row_telephone"></TextVIEw>          </linearLayout>          <linearLayout androID:layout_gravity="right" androID:layout_height="wrap_content" androID:ID="@+ID/linearLayout5" androID:layout_wIDth="match_parent">              <TextVIEw  androID:layout_height="fill_parent" androID:text="TextVIEw" androID:singleline="true" androID:ellipsize="marquee" androID:layout_wIDth="wrap_content" androID:ID="@+ID/pharmacy_row_distance"></TextVIEw>          </linearLayout>      </linearLayout>          </linearLayout>

解决方法 而不是这个

public IconListVIEwAdapterPharmacy(Context cont,Location l){    super(cont,items);    this.cont = cont;    this.items = items;    this.l = l;}

做这个

public IconListVIEwAdapterPharmacy(Context cont,items);    this.l = l;}

然后在getVIEw访问项中使用getItem(position)而不是items.get(position)并获取上下文调用getContext().

不知道这是否会改善性能.但尝试没有害处.这也是正确的方法.

编辑：
 如果您有要下载和显示的配置文件图像,可以像以后一样获取地址并更新UI.

String add = "" + o.getAddress();if (TextUtils.IsEmpty(add)) {    // download the geolocation. pass the position to the downloader thread which will update the item at position with address,after fetching is complete.    new GetAddresstask(position).execute(o);}

这将释放UI线程专注于显示ListvIEw.

class GetAddresstask extends Asynctask<.......> {     int mposition = -1;     public voID GetAddresstask(int position) {         mposition = position;     }     String doInBackground(parameters) {         return Geolocation.getaddress(parameter[0]);     }     voID onPostExecute(String result) { // this runs on UI thread.        // use mposition here.        // update addapter item with this address thats in 'result' variable.       // and call adapter.notifyDatasetInvalIDated()     }

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