ListView分批动态加载Item

这个例子主要实现ListView当滚动完毕所有可见Item后,继续加载未显示item例子,主要通过onScroll的监听来实现:

package com.example.listview;  
 
import android.app.ListActivity;  
import android.os.Bundle;  
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.AbsListView.OnScrollListener;  
import android.widget.LinearLayout.LayoutParams;  
 
public class ListViewLoading extends ListActivity implements OnScrollListener {  
 
    private ProgressBar progressBar;  
 
    private LayoutParams WClayoutParams = new LinearLayout.LayoutParams(  
            LinearLayout.LayoutParams.WRAP_CONTENT,  
            LinearLayout.LayoutParams.WRAP_CONTENT);  
 
    private LayoutParams FFlayoutParams = new LinearLayout.LayoutParams(  
            LinearLayout.LayoutParams.FILL_PARENT,  
            LinearLayout.LayoutParams.FILL_PARENT);  
 
    private ListViewAdapter adapter = new ListViewAdapter();  
 
    class ListViewAdapter extends BaseAdapter {  
        int count = 5;  
 
        public int getCount() {  
            return count;  
        }  
 
        public Object getItem(int pos) {  
            return pos;  
        }  
 
        public long getItemId(int pos) {  
            return pos;  
        }  
 
        public View getView(int pos, View v, ViewGroup p) {  
            TextView view = new TextView(ListViewLoading.this);  
            view.setText("The item position  " + pos);  
            view.setTextSize(20f);  
            view.setHeight(80);  
            return view;  
        }  
    }  
 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        LinearLayout layout = new LinearLayout(this);  
        layout.setOrientation(LinearLayout.HORIZONTAL);  
        progressBar = new ProgressBar(this);  
        progressBar.setPadding(0, 0, 15, 0);  
        layout.addView(progressBar, WClayoutParams);  
 
        TextView textView = new TextView(this);  
        textView.setText("数据加载中...");  
        textView.setGravity(Gravity.CENTER_VERTICAL);  
 
        layout.addView(textView, FFlayoutParams);  
        layout.setGravity(Gravity.CENTER);  
 
        LinearLayout loadingLayout = new LinearLayout(this);  
        loadingLayout.addView(layout, WClayoutParams);  
        loadingLayout.setGravity(Gravity.CENTER);  
 
        ListView listView = getListView();  
        listView.addFooterView(loadingLayout);  
        setListAdapter(adapter);  
        listView.setOnScrollListener(this);  
        // registerForContextMenu(listView);  
    }  
 
    private int lastItem = 0;  
 
    // 每次ListView被滚动时调用  
    @Override 
    public void onScrollStateChanged(AbsListView view, int scrollState) {  
        // TODO Auto-generated method stub  
        if (lastItem == adapter.count  
                && scrollState == OnScrollListener.SCROLL_STATE_IDLE) {  
            adapter.count += 3;  
            adapter.notifyDataSetChanged();  
        }  
    }  
 
    @Override 
    public void onScroll(AbsListView view, int firstVisibleItem,  
            int visibleItemCount, int totalItemCount) {  
        lastItem = firstVisibleItem + visibleItemCount - 1;  
        System.out.println("firstVisibleItem:" + firstVisibleItem);  
        System.out.println("visibleItemCount:" + visibleItemCount);  
    }  
}