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);
	}
}

评论

1 楼 苹果超人 2011-06-14