ListView实现分页功能【附Demo源码】

来源:互联网 发布:淘宝客刷销量方法 编辑:程序博客网 时间:2024/04/29 07:24
Android market里软件列表,每页显示10条记录,没有显示上一页,下一页的按钮,依靠手滑动动态加载数据,当向下滚动时,最下边显示 Loading… 。数据加载结束,Loading底栏消失。关于ListView的分段显示,有现成的库可用,比如 cwac-endless, 这个库不好之处,就是底部Loading的View无法定制。还有一个在google code上的androidpageablelistview 这个可以实现基本的分页,有手动操作显示上一页,下一页的按钮。查阅了很多资料,发现其实ListView自带一个实现分页加载的方法,用到 addFooterView/removeView 这两个函数“添加”或“去掉“ListView页脚。下面是一个研究ListView分页时做的一个Demo,比较简单,我把思路我源码和大家分享一下,希望对大家有所帮助。
效果图:ListViewLoading.png
实现思路如是:用onScroll方法实现”滑动“后处理检查是否还有新的记录,如果有,调用 addFooterView,添加记录到adapter, adapter调用 notifyDataSetChanged 更新数据;如果没有记录了, 把自定义的mFooterView去掉。这里没有重写onScrollStateChanged函数,那么在onScroll就需要一个外部变量 mFirstCell记录滑动位置。

代码如下:

import android.app.ListActivity;import android.os.Bundle;import android.util.Log;import android.view.Gravity;import android.view.View;import android.view.ViewGroup;import android.widget.AbsListView;import android.widget.BaseAdapter;import android.widget.LinearLayout;import android.widget.ListView;import android.widget.ProgressBar;import android.widget.TextView;import android.widget.Toast;import android.widget.AbsListView.OnScrollListener;import android.widget.LinearLayout.LayoutParams;/**** @author huangbq**/public class MainActivity extends ListActivity implements OnScrollListener {private static final String TAG = "MainActivity";private listViewAdapter adapter = new listViewAdapter();ListView listView ;private int lastItem = 0;LinearLayout loadingLayout;/**  * 设置布局显示属性  */    private LayoutParams mLayoutParams =new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT);    /**  * 设置布局显示目标最大化属性  */    private LayoutParams FFlayoutParams =new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.FILL_PARENT);   private ProgressBar progressBar;@Overrideprotected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  Log.i(TAG, "onCreate(Bundle savedInstanceState)>>>>>>>>>>>>>>>" );     //线性布局  LinearLayout layout = new LinearLayout(this);    //设置布局 水平方向  layout.setOrientation(LinearLayout.HORIZONTAL);   //进度条  progressBar = new ProgressBar(this);   //进度条显示位置  progressBar.setPadding(0, 0, 15, 0);  //把进度条加入到layout中  layout.addView(progressBar, mLayoutParams);  //文本内容  TextView textView = new TextView(this);  textView.setText("加载中...");  textView.setGravity(Gravity.CENTER_VERTICAL);  //把文本加入到layout中  layout.addView(textView, FFlayoutParams);  //设置layout的重力方向,即对齐方式是  layout.setGravity(Gravity.CENTER);    //设置ListView的页脚layout  loadingLayout = new LinearLayout(this);  loadingLayout.addView(layout, mLayoutParams);  loadingLayout.setGravity(Gravity.CENTER);    //得到一个ListView用来显示条目  listView = getListView();  //添加到页脚显示  listView.addFooterView(loadingLayout);  //给ListView添加适配器  setListAdapter(adapter);  //给ListView注册滚动监听  listView.setOnScrollListener(this);}@Overridepublic void onScroll(AbsListView v, int firstVisibleItem,   int visibleItemCount, int totalItemCount) {  Log.i(TAG , "Scroll>>>first: " + firstVisibleItem + ", visible: " + visibleItemCount + ", total: " + totalItemCount);  lastItem = firstVisibleItem + visibleItemCount - 1;  Log.i(TAG , "Scroll>>>lastItem:" + lastItem);  //显示50条ListItem,即0-49,因为onScroll是在“滑动”执行过之后才触发,所以用adapter.count<=41作条件  if (adapter.count<=41) {   if (firstVisibleItem+visibleItemCount==totalItemCount) {    adapter.count += 10;    adapter.notifyDataSetChanged();    listView.setSelection(lastItem);    int currentPage=adapter.count/10;    Toast.makeText(getApplicationContext(), "第"+currentPage+"页", Toast.LENGTH_LONG).show();   }  }  else {    listView.removeFooterView(loadingLayout);  }    }@Overridepublic void onScrollStateChanged(AbsListView v, int state) {  if (lastItem == adapter.count && state == OnScrollListener.SCROLL_STATE_IDLE) {   Log.i(TAG,"ScrollStateChanged>>>state:"+state+"lastItem:" + lastItem);   //显示50条ListItem,即0-49,因为onScrollStateChanged是在“拖动滑动”执行过之后才触发,所以用adapter.count<=41作条件   if (adapter.count<=41) {    adapter.count += 10;    adapter.notifyDataSetChanged();   }  }}  /**   * 要用用于生成显示数据   * @author huangbq   *   */class listViewAdapter extends BaseAdapter {  int count = 10;  public int getCount() {   Log.i(TAG, "getCount>>>count:" + count);   return count;  }  public Object getItem(int pos) {   Log.i(TAG, "getItem>>>pos:" + pos);   return pos;  }  public long getItemId(int pos) {   Log.i(TAG, "getItemId>>>ItemId:" + pos);   return pos;  }  public View getView(int pos, View v, ViewGroup p) {   Log.i(TAG, "getView>>>pos:" + pos);   TextView view;   if (v==null) {    view = new TextView(MainActivity.this);   }   else {    view=(TextView)v;   }   view.setText("ListItem " + pos);   view.setTextSize(20f);   view.setGravity(Gravity.CENTER);   view.setHeight(60);   return view;  }}}


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