Android使用listview实现分页刷新（线程休眠模拟）

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/activity_main" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.example.administrator.day08.MainActivity"> <ListView android:id="@+id/lv" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_alignParentTop="true" android:layout_alignParentStart="true" /></RelativeLayout>

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:orientation="vertical" android:layout_width="match_parent"  android:layout_height="match_parent">  <TextView    android:text="Tile"    android:textSize="30dp"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:id="@+id/textView" />  <TextView    android:text="Message"    android:textSize="20dp"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:id="@+id/textView2" /></LinearLayout>

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:orientation="horizontal" android:layout_width="match_parent"  android:layout_height="match_parent" android:gravity="center">  <ProgressBar    style="?android:attr/progressBarStyle"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:layout_gravity="center"    android:id="@+id/progressBar" />  <TextView    android:text="玩命加载中"    android:layout_width="wrap_content"    android:layout_height="wrap_content"    android:id="@+id/textView3" /></LinearLayout>

 public class News {   String title;   String message; }

import android.content.DialogInterface;import android.os.Handler;import android.os.Message;import android.support.v7.app.AlertDialog;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.view.ViewGroup;import android.widget.AbsListView;import android.widget.AdapterView;import android.widget.BaseAdapter;import android.widget.ListView;import android.widget.TextView;import java.util.ArrayList;import java.util.List;/** * Created by panchengjia on 2016/11/29. */public class MainActivity extends AppCompatActivity implements AbsListView.OnScrollListener{  private ListView lv;  private List<News> news;//声明存储新闻标题与内容的List  private int total=1;//计数器(设置默认从1开始)用于集合内数据初始化  MyAdapter adapter;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    lv= (ListView) findViewById(R.id.lv);    //为当前ListView设置OnScrollListener实现分页刷新    lv.setOnScrollListener(this);    //将login_item(下拉刷新效果的item)通过布局 填充器声明    View v = getLayoutInflater().inflate(R.layout.login_item,null);    //将login_item设置到ListView页脚    lv.addFooterView(v);    //实例化存储内容资源的List    news = new ArrayList<>();    //调用初始化List的方法    initList();    adapter = new MyAdapter();    //设置单击item的事件    lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {      @Override      public void onItemClick(AdapterView<?> parent, View view, int position, long id) {        show(view);//事件处理为调用show方法（显示AlertDialog对话框）      }    });    lv.setAdapter(adapter);  }  //AlertDialog对话框的调用这里就不多说了，前期有专门的博文解释  public void show(View v){    AlertDialog.Builder builder = new AlertDialog.Builder(this);    TextView title = (TextView) v.findViewById(R.id.textView);    TextView message = (TextView) v.findViewById(R.id.textView2);    builder.setTitle(title.getText().toString());    builder.setMessage(message.getText().toString());    builder.setPositiveButton("已经浏览完毕", new DialogInterface.OnClickListener() {      @Override      public void onClick(DialogInterface dialog, int which) {      }    });    builder.show();  }  //初始化List内的元素，模拟每次可刷新10条信息  private void initList() {    for(int i=1;i<=10;i++){      News n = new News();      //加total是因为total在刷新页面后不会继续从一开始      n.title = "Title--"+total;      n.message="Message"+total;      news.add(n);      total++;    }  }//  int currenVisibleItemCount;//声明截止当前页面看到的item总数（演示用）  boolean isLastRow=false;//判断是否到ListView的最后一个item  @Override  public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {    //firstVisibleItem位可见页面的第一条在Arraylist中的下标，visibleItemCount为当前页面item数//    currenVisibleItemCount = firstVisibleItem+visibleItemCount-1=totalItemCount;（演示用）    if(firstVisibleItem+visibleItemCount==totalItemCount&&totalItemCount>0){      isLastRow=true;//判断已经到最后一个item（即为footerView）    }  }  @Override  public void onScrollStateChanged(AbsListView view, int scrollState) {    /*判断是否刷新页面之前，解释一下scrollState的三种状态    * 1.scrollState = SCROLL_STATE_TOUCH_SCROLL为手指按住屏幕滚动（未脱离屏幕）；    * 2.scrollState = SCROLL_STATE_FLING可以理解为手指离开屏幕前，用力滑了一下，    *    手指离开后，页面已然保持滚动；    * 3.scrollState = SCROLL_STATE_IDLE手指未接触屏幕，且屏幕页面保持静止    * 开启刷新页面的线程前，确保ListView已经到最后一行（Item）并且屏幕页面保持静止    * */    if(isLastRow&&scrollState==SCROLL_STATE_IDLE){      new Thread(new MyThread()).start();    }  }  //创建分页刷新线程（模拟刷新）  class MyThread implements Runnable{    @Override    public void run() {      try {        Thread.sleep(500);//设置线程休眠时间为500毫秒刷新一次      } catch (InterruptedException e) {        e.printStackTrace();      }      initList();//重新初始化List      //线程内调用Handler执行页面刷新（后面会写文对handler进行详细剖析）      handler.sendEmptyMessage(1);    }  }  Handler handler = new Handler(){    @Override    public void handleMessage(Message msg) {      super.handleMessage(msg);      switch (msg.what){        case 1:          //强制调用适配器的getView来刷新每个Item的内容。          adapter.notifyDataSetChanged();          break;      }    }  };  //自定义适配器  class MyAdapter extends BaseAdapter{    @Override    public int getCount() {      return news.size();    }    @Override    public Object getItem(int position) {      return news.get(position);    }    @Override    public long getItemId(int position) {      return position;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {      ViewHolder vh;      if(convertView==null){        convertView = getLayoutInflater().inflate(R.layout.item,null);        vh=new ViewHolder();        vh.message = (TextView) convertView.findViewById(R.id.textView2);        vh.title= (TextView) convertView.findViewById(R.id.textView);        convertView.setTag(vh);      }      vh= (ViewHolder) convertView.getTag();      vh.title.setText(news.get(position).title);      vh.message.setText(news.get(position).message);      return convertView;    }    class ViewHolder{      TextView title;      TextView message;    }  }}