ListView中的滚动事件及自动翻页功能

ListView的滚动事件
             为ListView添加滚动事件
           setOnScrollListener(OnScrollListener listener)
  OnScrollListener
         void onScrollStateChanged(AbsListView view,int scrollState)
      SCROLL_STATE_IDLE
                       SCROLL_STATE_TOUCH_SCROLL
      SCROLL_STATE_FLING
 void Scroll(AbsListView view,int firstVisibleItem,int visibleItemCounyt,
        int totalItemCount)


ListView滑动到底部自动翻页
      要点
         为自定义适配器，添加追加数据集的方法
 为ListView添加滚动事件监听器
      在onScroll方法中计算lastVisibleItem

   在onScrollStateChanged方法中，判断是否滑动到底部，如果滑动到底部加载新数据，并刷新listview

下面是一个能够实现自动翻页功能的小项目

主Activity：

          

package com.example.listview1;import java.util.ArrayList;import android.app.Activity;import android.app.AlertDialog;import android.os.Bundle;import android.view.View;import android.widget.AbsListView;import android.widget.AbsListView.OnScrollListener;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.ListView;public class MainActivity extends Activity {    private ListView lvMusics;    private MusicAdapter adapter;    private int page;    private AlertDialog dialog;        private void setupView(){    lvMusics = (ListView) findViewById(R.id.lvMusics);    page = 1;    adapter = new MusicAdapter(this, MusicBiz.getMusics(page++));    lvMusics.setAdapter(adapter);                }        private void addListener(){    lvMusics.setOnScrollListener(new OnScrollListener() {    private int lastVisibleItem;    @Overridepublic void onScrollStateChanged(AbsListView view, int scrollState) {// TODO Auto-generated method stubif(scrollState == OnScrollListener.SCROLL_STATE_IDLE&& lastVisibleItem == adapter.getCount() - 1){//加载新数据ArrayList<Music> musics = MusicBiz.getMusics(page++);adapter.addData(musics);}}@Overridepublic void onScroll(AbsListView view, int firstVisibleItem,int visibleItemCount, int totalItemCount) {// TODO Auto-generated method stub//计算当前可见的最后一个Item   lastVisibleItem = firstVisibleItem + visibleItemCount - 1;}});    }@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);setupView();addListener();}}

                      

实现的对象：

       

       为了省事，代码几乎跟前几次一样。。。。。。

       

package com.example.listview1;public class Music {     private String name;     private String album;     private int id;     private String duration;     private String artist;     private String musicPath;     private String albumPicPath;public String getName() {return name;}public void setName(String name) {this.name = name;}public String getAlbum() {return album;}public void setAlbum(String album) {this.album = album;}public int getId() {return id;}public void setId(int id) {this.id = id;}public String getDuration() {return duration;}public void setDuration(String duration) {this.duration = duration;}public String getArtist() {return artist;}public void setArtist(String artist) {this.artist = artist;}public String getMusicPath() {return musicPath;}public void setMusicPath(String musicPath) {this.musicPath = musicPath;}public String getAlbumPicPath() {return albumPicPath;}public void setAlbumPicPath(String albumPicPath) {this.albumPicPath = albumPicPath;}    public String toString(){return "Music [id=" + id +",name=" + name + ",album=" + album +",duration=" + duration + ",artist=" + artist +",musicPath=" + musicPath + ",albumPicPath=" + albumPicPath + "]";}}

    适配器几乎也没有变化：

                         

package com.example.listview1;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.TextView;public class MusicAdapter extends BaseAdapter {    private ArrayList<Music> musics;    private LayoutInflater inflater;    public MusicAdapter(Context context,ArrayList<Music> musics) {if(musics != null)     this.musics = musics;elsethis.musics = new ArrayList<Music>();this.inflater = LayoutInflater.from(context);}public void addData(ArrayList<Music> musics){if(musics != null){this.musics.addAll(musics);notifyDataSetChanged();}}@Overridepublic int getCount() {// TODO Auto-generated method stubreturn musics.size();}@Overridepublic Music getItem(int position) {// TODO Auto-generated method stubreturn musics.get(position);}@Overridepublic long getItemId(int position) {// TODO Auto-generated method stubreturn getItem(position).getId();}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {// TODO Auto-generated method stubViewHolder holder = null;if(convertView == null){convertView = inflater.inflate(R.layout.item, null);holder = new ViewHolder();holder.tvName = (TextView)convertView.findViewById(R.id.tvName);holder.tvAlbum = (TextView)convertView.findViewById(R.id.tvAlbum);holder.tvArtist = (TextView)convertView.findViewById(R.id.tvArtist);holder.tvDuration = (TextView)convertView.findViewById(R.id.tvDuration);convertView.setTag(holder);}else{holder = (ViewHolder)convertView.getTag();}Music m = musics.get(position);holder.tvName.setText(m.getName());holder.tvAlbum.setText(m.getAlbum());holder.tvArtist.setText(m.getArtist());holder.tvDuration.setText(m.getDuration());return convertView;}class ViewHolder{private TextView tvName;private TextView tvDuration;private TextView tvArtist;private TextView tvAlbum;}}

操作者同样的一组数据：

           

package com.example.listview1;import java.util.ArrayList;public class MusicBiz {        public static ArrayList<Music> getMusics(int page){        ArrayList<Music> musics = new ArrayList<Music>();        int i=(page - 1) * 20 +1;        int end = i+20;        for(;i<end;i++){        Music m = new Music();        m.setId(i);        m.setName("歌曲" + i);        m.setAlbum("专辑" + i);        m.setAlbumPicPath("D:/www.123/123/1.jpg");        m.setDuration("14:23");        m.setArtist("陈奕迅");        m.setMusicPath("http://www.123wer/123/music.jpg");        musics.add(m);        }                                 return musics;        }}

布局相同：

        

<ListView    android:id="@+id/lvMusics"    android:layout_width="match_parent"    android:layout_height="match_parent"     xmlns:android="http://schemas.android.com/apk/res/android"     />

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="horizontal" >    <ImageView         android:layout_width="64dp"        android:layout_height="64dp"        android:src="@drawable/image"/>     <TableLayout          android:layout_width="0dp"         android:layout_height="match_parent"         android:layout_weight="1.0"         android:stretchColumns="*">         <TableRow              android:layout_height="0dp"             android:layout_weight="1.0">             <TextView                  android:id="@+id/tvName"                 android:layout_height="match_parent"                 android:gravity="center_vertical"                 android:textSize="20sp"/>             <TextView                  android:id="@+id/tvDuration"                 android:layout_height="match_parent"                 android:gravity="center_vertical"                 android:textSize="20sp"/>         </TableRow>         <TableRow              android:layout_height="0dp"             android:layout_weight="1.0">             <TextView                  android:id="@+id/tvArtist"                 android:layout_height="match_parent"                 android:gravity="center_vertical"                 android:textSize="20sp"/>             <TextView                  android:id="@+id/tvAlbum"                 android:layout_height="match_parent"                 android:gravity="center_vertical"                 android:textSize="20sp"/>         </TableRow>     </TableLayout></LinearLayout>