android实现listview分页的方法

本文实例讲述了Android实现listview分页的方法。分享给大家供大家参考。具体分析如下：

最近做了下listview的分页,跟WEB上的分页是一个意思,需要那几个分页参数,不同的是sqlite中分页的查询语句，简便的方法需要用Limit,Offset关键字,前者是查询每页展示的记录数,后者是越过多少记录数,说得明白点就是忽略前面多少行记录之后,取多少行记录

我分页采用了一个重要的类Page,通过封装Page类,做为参数传递进来,返回出去也是个Page对象

import java.util.Collections; 
import java.util.List; 
 
public class Page<T> { 
  //-- 公共变量 --// 
  public static final String ASC = "asc"; 
  public static final String DESC = "desc"; 
  //-- 分页参数 --// 
  protected int pageNo = 0;// 当前页号<跟取数据的方式有关系> 
  protected int pageSize = 1;// 每页显示的记录数 
  protected String orderBy = null; 
  protected String order = null; 
  protected boolean autoCount = true; 
  //-- 返回结果 --// 
  protected List<T> result = Collections.emptyList(); 
  protected long totalCount = -1;// 总记录数 
  //-- 构造函数 --// 
  public Page() { 
  } 
  public Page(final int pageSize) { 
    setPageSize(pageSize); 
  } 
  public Page(final int pageSize, final boolean autoCount) { 
    setPageSize(pageSize); 
    setAutoCount(autoCount); 
  } 
  //-- 访问查询参数函数 --// 
   
  public int getPageNo() { 
    return pageNo; 
  } 
   
  public void setPageNo(final int pageNo) { 
    this.pageNo = pageNo; 
    if (pageNo < 0) { 
      this.pageNo = 0; 
    } 
  } 
   
  public int getPageSize() { 
    return pageSize; 
  } 
   
  public void setPageSize(final int pageSize) { 
    this.pageSize = pageSize; 
    if (pageSize < 0) { 
      this.pageSize = 0; 
    } 
  } 
   
  public int getFirst() { 
    return (pageNo * pageSize) + 1; 
  } 
   
  public String getOrderBy() { 
    return orderBy; 
  } 
   
  public void setOrderBy(final String orderBy) { 
    this.orderBy = orderBy; 
  } 
   
  public String getOrder() { 
    return order; 
  } 
   
  public void setOrder(String order) { 
    this.order = order; 
  } 
   
  public boolean isAutoCount() { 
    return autoCount; 
  } 
   
  public void setAutoCount(final boolean autoCount) { 
    this.autoCount = autoCount; 
  } 
  //-- 访问查询结果函数 --// 
   
  public List<T> getResult() { 
    return result; 
  } 
   
  public void setResult(final List<T> result) { 
    this.result = result; 
  } 
   
  public long getTotalCount() { 
    return totalCount; 
  } 
   
  public void setTotalCount(final long totalCount) { 
    this.totalCount = totalCount; 
  } 
   
  public long getTotalPages() { 
    if (totalCount < 0) 
      return -1; 
    long count = totalCount / pageSize; 
    if (totalCount % pageSize > 0) { 
      count++; 
    } 
    return count; 
  } 
   
  public boolean isHasNext() { 
    return (pageNo + 1 < getTotalPages()); 
  } 
   
  public int getNextPage() { 
    if (isHasNext()) 
      return pageNo + 1; 
    else 
      return pageNo; 
  } 
   
  public boolean isHasPre() { 
    return (pageNo - 1 >= 0); 
  } 
   
  public int getPrePage() { 
    if (isHasPre()) 
      return pageNo - 1; 
    else 
      return pageNo; 
  } 
}

下面是封装的POJO对象,界面listview的item展示就是靠它

public class Record { 
  private Integer rId; 
  private String fromUser; 
  private String toUser; 
  private String content; 
  private String rTime; 
  private Integer isReaded; 
  public Integer getrId() { 
    return rId; 
  } 
  public void setrId(Integer rId) { 
    this.rId = rId; 
  } 
  public String getFromUser() { 
    return fromUser; 
  } 
  public void setFromUser(String fromUser) { 
    this.fromUser = fromUser; 
  } 
  public String getToUser() { 
    return toUser; 
  } 
  public void setToUser(String toUser) { 
    this.toUser = toUser; 
  } 
  public String getContent() { 
    return content; 
  } 
  public void setContent(String content) { 
    this.content = content; 
  } 
  public String getrTime() { 
    return rTime; 
  } 
  public void setrTime(String rTime) { 
    this.rTime = rTime; 
  } 
  public Integer getIsReaded() { 
    return isReaded; 
  } 
  public void setIsReaded(Integer isReaded) { 
    this.isReaded = isReaded; 
  }
}

好吧，来看下DAO类里的重要方法同样是Page对象,在DAO类里做的操作就是对总记录数和结果list进行赋值

public Page<Record> getRecordPage(Page<Record> page, String loginName, 
      String contactName) { 
    int pageSize = page.getPageSize(); 
    int pageNo = page.getPageNo(); 
    String sql = "select * from " 
        + ContactsManagerDbAdapter.TABLENAME_RECORD 
        + " where (fromUser = ? and toUser = ?) or (fromUser = ? and toUser = ?)" 
        + " Limit " + String.valueOf(pageSize) + " Offset " 
        + String.valueOf(pageNo * pageSize); 
    String[] selectionArgs = { loginName, contactName, contactName, 
        loginName }; 
    Cursor cursor = mSQLiteDatabaseWritable.rawQuery(sql, selectionArgs); 
    List<Record> result = new ArrayList<Record>(); 
    for(cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()){ 
      Record record = new Record(); 
      record.setrId(cursor.getInt(0)); 
      record.setFromUser(cursor.getString(1)); 
      record.setToUser(cursor.getString(2)); 
      record.setContent(cursor.getString(3)); 
      record.setrTime(cursor.getString(4)); 
      record.setIsReaded(cursor.getInt(5)); 
      result.add(record); 
    } 
    page.setTotalCount(getRowCount(loginName, contactName)); 
    page.setResult(result); 
    cursor.close(); 
    return page; 
} 
 
public int getRowCount(String loginName, String contactName){ 
    String sql = "select * from " 
      + ContactsManagerDbAdapter.TABLENAME_RECORD 
      + " where (fromUser = ? and toUser = ?) or (fromUser = ? and toUser = ?)"; 
    String[] selectionArgs = { loginName, contactName, contactName,
        loginName }; 
    Cursor cursor = mSQLiteDatabaseWritable.rawQuery(sql, selectionArgs); 
    int count = cursor.getCount(); 
    cursor.close(); 
    return count; 
} 

关于listview的展示和自定义适配器,在此不提起,总之界面上上一页和下一页按钮的点击事件需要刷新listview

public class ChatHistory extends Activity { 
  ListView historyView; 
  Button prevPageBtn; 
  Button nextPageBtn; 
  TextView historyPageTv; 
  Button backChatsHistoryBtn; 
  Button deleteHistoryBtn; 
  List<Record> historyRecordList;  
  Page<Record> page; 
  String loginName; 
  String contactName; 
  ChatHistoryService chatHistoryService; 
  ContactsManagerDbAdapter dbAdapter; 
  private BaseAdapter adapter; 
  private static final int STATUS_CHANGE = 0; 
  private Handler mHandler; 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    // TODO Auto-generated method stub 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.chats_history); 
    historyView = (ListView) findViewById(android.R.id.list); 
    prevPageBtn = (Button) findViewById(R.id.chat_prev_page); 
    nextPageBtn = (Button) findViewById(R.id.chat_next_page); 
    historyPageTv = (TextView) findViewById(R.id.history_page); 
    backChatsHistoryBtn = (Button) findViewById(R.id.back_chats_history); 
    deleteHistoryBtn = (Button) findViewById(R.id.delete_history); 
    SharedPreferences sharedata = ChatHistory.this.getSharedPreferences("data", 0); 
    loginName = sharedata.getString("loginName", ""); 
    contactName = getIntent().getStringExtra("contactName"); 
    dbAdapter = new ContactsManagerDbAdapter(getApplicationContext()); 
    dbAdapter.open(); 
    chatHistoryService = new ChatHistoryService(ChatHistory.this);
    page = new Page<Record>(); 
    page.setPageSize(8); 
    page = chatHistoryService.getHistoryPage(page, loginName, contactName, dbAdapter); 
    historyRecordList = page.getResult(); 
    updateTextView(); 
    prevPageBtn.setOnClickListener(prevPageButtonListener); 
    nextPageBtn.setOnClickListener(nextPageButtonListener); 
    backChatsHistoryBtn.setOnClickListener(backButtonListener); 
    deleteHistoryBtn.setOnClickListener(deleteHistoryButtonListener); 
    adapter = new HistoryListAdapter(ChatHistory.this); 
    historyView.setAdapter(adapter); 
    mHandler = new Handler(){  
       public void handleMessage(Message msg) { 
          switch(msg.what){ 
          case STATUS_CHANGE: 
            // 处理UI更新等操作 
            updateUI(); 
          } 
       }; 
    }; 
  } 
  private void updateUI() { 
    //详细的更新 
    adapter.notifyDataSetChanged();// 更新ListView 
    updateTextView(); 
  } 
   
  private void updateTextView(){    
    if(historyRecordList.size() == 0){ 
      historyPageTv.setText(0 + "/" + 0); 
    } else{ 
      historyPageTv.setText(page.getPageNo() + 1 + "/" + page.getTotalPages()); 
    } 
  } 
  public class HistoryListAdapter extends BaseAdapter{ 
    private class RecentViewHolder { 
      TextView sender_context; 
      TextView rTime; 
    } 
    Context context; 
    LayoutInflater mInflater; 
    public HistoryListAdapter(Context context){ 
      this.context = context; 
      mInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
    } 
    @Override 
    public int getCount() { 
      // TODO Auto-generated method stub 
      return historyRecordList.size(); 
    } 
    @Override 
    public Object getItem(int position) { 
      // TODO Auto-generated method stub 
      return historyRecordList.get(position); 
    } 
    @Override 
    public long getItemId(int position) { 
      // TODO Auto-generated method stub 
      return position; 
    } 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
      // TODO Auto-generated method stub 
      RecentViewHolder holder; 
      if (convertView == null) { 
        convertView = mInflater.inflate(R.layout.message_layout, null); 
        holder = new RecentViewHolder(); 
        holder.sender_context = (TextView) convertView 
            .findViewById(R.id.message_view_sender_content);
        holder.rTime = (TextView) convertView 
            .findViewById(R.id.message_view_timestamp); 
        convertView.setTag(holder); 
      } else { 
        holder = (RecentViewHolder) convertView.getTag(); 
      } 
      Record record = historyRecordList.get(position); 
      if (record != null) { 
        holder.sender_context.setText(record.getFromUser() + ":" + record.getContent()); 
        holder.rTime.setText(record.getrTime()); 
      } 
      return convertView; 
    } 
  } 
   
  OnClickListener prevPageButtonListener = new OnClickListener(){ 
    @Override 
    public void onClick(View v) { 
      // TODO Auto-generated method stub 
      if(page.isHasPre()){ 
        page.setPageNo(page.getPageNo() - 1); 
        historyRecordList = chatHistoryService.getHistoryPage(page, loginName, contactName, dbAdapter).getResult(); 
        Message msg = new Message(); 
        msg.what = STATUS_CHANGE; 
        mHandler.sendMessage(msg);// 向Handler发送消息,更新UI 
      } 
    } 
  }; 
   
  OnClickListener nextPageButtonListener = new OnClickListener(){ 
    @Override 
    public void onClick(View v) { 
      // TODO Auto-generated method stub 
      if(page.isHasNext()){ 
        page.setPageNo(page.getPageNo() + 1); 
        historyRecordList = chatHistoryService.getHistoryPage(page, loginName, contactName, dbAdapter).getResult(); 
        Message msg = new Message(); 
        msg.what = STATUS_CHANGE; 
        mHandler.sendMessage(msg);// 向Handler发送消息,更新UI 
      } 
    } 
  }; 
   
  OnClickListener deleteHistoryButtonListener = new OnClickListener() { 
    @Override 
    public void onClick(View v) { 
      // TODO Auto-generated method stub      
    } 
  }; 
   
  OnClickListener backButtonListener = new OnClickListener() { 
    @Override 
    public void onClick(View v) { 
      // TODO Auto-generated method stub 
      // 返回到聊天界面 
      finish(); 
      dbAdapter.close(); 
    } 
  }; 
  @Override 
  public boolean onKeyDown(int keyCode, KeyEvent event) { 
    // 按下键盘上返回按钮 
    if (keyCode == KeyEvent.KEYCODE_BACK) { 
      finish(); 
      dbAdapter.close(); 
      return true; 
    } else { 
      return super.onKeyDown(keyCode, event); 
    }
  }
}

上一页，下一页所做的操作也就是在判断是否有上一页和下一页的情况下对页号pageNo的加减操作
最后写上ChatHistoryService.java总觉得是多余的

public class ChatHistoryService { 
  Context context; 
  public ChatHistoryService(Context context) { 
    this.context = context; 
  } 
  public Page<Record> getHistoryPage(Page<Record> page, String loginName, 
      String contactName, ContactsManagerDbAdapter dbAdapter) { 
    RecordDao recordDao = new RecordDao(dbAdapter); 
    return recordDao.getRecordPage(page, loginName, contactName); 
  } 
  public int deleteHistory(String loginName, 
      String contactName, ContactsManagerDbAdapter dbAdapter){ 
    RecordDao recordDao = new RecordDao(dbAdapter); 
    return recordDao.deleteHistoryRecord(loginName, contactName); 
  } 
} 

顺带放上XML布局文件吧
chats_history.xml

<?xml version="1.0" encoding="UTF-8"?> 
<!-- 与好友聊天窗口.xml --> 
<LinearLayout xmlns:android="Http://schemas.android.com/apk/res/android"
  android:orientation="vertical" android:layout_width="fill_parent" 
  android:layout_height="fill_parent" android:background="@color/white"> 
  <ListView android:id="@android:id/list" android:layout_width="fill_parent" 
    android:layout_height="200dip" android:layout_weight="1" 
    android:transcriptMode="nORMal" android:fadingEdge="none" 
    android:padding="4px" android:fastScrollEnabled="true" 
    android:smoothScrollbar="false" 
    android:focusable="true" android:dividerHeight="0dip" 
    android:cacheColorHint="#00000000" android:divider="@drawable/divider" /> 
  <!-- 引用聊天内容.xml --> 
  <LinearLayout android:layout_width="fill_parent" 
    android:layout_height="50.0dip" android:orientation="horizontal" 
    android:background="#ccc" android:paddingLeft="3Dip" 
    android:paddingTop="3dip"> 
    <Button android:id="@+id/chat_prev_page" 
      android:layout_width="wrap_content" android:layout_height="wrap_content" 
      android:background="@drawable/chat_prev_page" /> 
    <TextView android:id="@+id/history_page" android:layout_width="30.0dip" 
      android:layout_height="25.0dip" android:gravity="center" 
      android:text="1/1"/> 
    <Button android:id="@+id/chat_next_page" android:layout_width="wrap_content" 
      android:layout_height="wrap_content" android:background="@drawable/chat_next_page" /> 
    <Button android:id="@+id/delete_history" android:layout_width="wrap_content" 
      android:layout_height="wrap_content" android:background="@drawable/delete_history_button" /> 
    <Button android:id="@+id/export_history" android:layout_width="wrap_content" 
      android:layout_height="wrap_content" android:background="@drawable/export_history_button" /> 
    <Button android:id="@+id/back_chats_history" 
      android:layout_width="wrap_content" android:layout_height="wrap_content"  
      android:background="@drawable/back_btn"/> 
  </LinearLayout> 
</LinearLayout>

 message_layout.xml

<?xml version="1.0" encoding="UTF-8"?> 
<!-- 消息内容的展示 --> 
<LinearLayout 
 xmlns:android="http://schemas.android.com/apk/res/android" 
 android:layout_width="fill_parent" 
 android:layout_height="wrap_content" 
 android:orientation="vertical" 
 > 
 <!-- android:background="@drawable/item_style" --> 
  <TextView android:id="@+id/message_view_sender_content" 
    android:layout_width="wrap_content" android:layout_height="wrap_content" 
    android:autoLink="all" /> 
  <TextView android:id="@+id/message_view_timestamp" 
    android:layout_alignParentRight="true" android:layout_width="wrap_content" 
    android:layout_height="wrap_content" android:layout_below="@+id/message_view_message" 
    android:layout_gravity="right" /> 
</LinearLayout> 

最后来看看效果吧,别欺负我没贴上数据库建表语句,看下我的POJO类就知道我数据库表怎么建的

希望本文所述对大家的Android程序设计有所帮助。

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