android listview ProgressBar listview底部实现加载分页的效果

package com.wzt; import java.util.ArrayList; import java.util.List; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import com.wzt.util.AsyncImageLoader; import com.wzt.util.AsyncImageLoader.ImageCallback; import com.wzt.util.HttpUtil; import android.app.ListActivity; import android.app.ProgressDialog; import android.content.Context; import android.graphics.drawable.Drawable; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AbsListView; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.LinearLayout; import android.widget.ListView; import android.widget.TextView; import android.widget.AbsListView.OnScrollListener; public class UserActivity extends ListActivity implements OnScrollListener { private ListView listView; private HomeAdapter adapter; private JSONArray array; private AsyncImageLoader asyncImageLoader; private Handler handler; private ProgressDialog progressDialog; private LinearLayout list_footer; private LinearLayout loading; private List<JSONObject> list;// 微博数据列表 private ExecutorService executorService; private int TOTAL_PAGE = 0;// 当前已经记在的微博页数 private static int THREADPOOL_SIZE = 4;// 线程池的大小 private int visibleLastIndex = 0; // 最后的可视项索引 private int visibleItemCount; // 当前窗口可见项总数 public static int SCROLL_STATE_IDLE = 2; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.user); setUpViews(); progressDialog = new ProgressDialog(UserActivity.this);// 生成一个进度条 progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER); progressDialog.setTitle("请稍等"); progressDialog.setMessage("正在读取数据中!"); handler = new GetHomeTimeLineHandler(); executorService.submit(new GetHomeTimeLineThread());// 耗时操作,开启一个新线程获取数据 progressDialog.show(); } private void setUpViews() { list_footer = (LinearLayout) LayoutInflater.from(UserActivity.this) .inflate(R.layout.list_footer, null); loading = (LinearLayout) list_footer.findViewById(R.id.loading); listView = getListView(); listView.addFooterView(list_footer);// 这儿是关键中的关键呀，利用FooterVIew分页动态加载 list = new ArrayList<JSONObject>(); executorService = Executors.newFixedThreadPool(THREADPOOL_SIZE); // 实现监听器 listView.setOnScrollListener(this); //添加滑动监听 //loading.setVisibility(View.VISIBLE);// 隐藏下方的进度条 } class GetHomeTimeLineHandler extends Handler { @Override public void handleMessage(Message msg) { adapter = new HomeAdapter(UserActivity.this, list); if (TOTAL_PAGE > 1) { listView.setVisibility(View.GONE); adapter.notifyDataSetChanged(); listView.setVisibility(View.VISIBLE); } if (TOTAL_PAGE == 1) { listView.setAdapter(adapter); } //listView.setSelection(visibleLastIndex - visibleItemCount + 1); //设置选中项 progressDialog.dismiss();// 关闭进度条 loading.setVisibility(View.GONE);// 隐藏下方的进度条 } } class GetHomeTimeLineThread implements Runnable { @Override public void run() { try { Thread.sleep(2000); refreshList(); Message msg = handler.obtainMessage();// 通知线程来处理范围的数据 msg.sendToTarget(); } catch (InterruptedException e) { e.printStackTrace(); } } } private void refreshList() { String url = HttpUtil.BASE_URL + "android/user/user_json_3.php?page=" + TOTAL_PAGE + "&r=" + Math.random(); String jsonStr = HttpUtil.queryStringForPost(url); try { JSONObject dataObj = new JSONObject(jsonStr).getJSONObject("posts"); array = dataObj.getJSONArray("info"); if (array != null && array.length() > 0) { TOTAL_PAGE++; for (int i = 0; i < array.length(); i++) { list.add(array.optJSONObject(i)); } } } catch (JSONException e) { e.printStackTrace(); } } @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { this.visibleItemCount = visibleItemCount; visibleLastIndex = firstVisibleItem + visibleItemCount; } @Override public void onScrollStateChanged(AbsListView view, int scrollState) { int lastIndex = adapter.getCount() + 1; Log.e("AdapterNumber:", lastIndex+""); Log.e("visibleLastIndex:", visibleLastIndex+""); Log.e("scrollState:", scrollState+""); loading.setVisibility(View.VISIBLE); if (visibleLastIndex == lastIndex && scrollState == SCROLL_STATE_IDLE) { executorService.submit(new GetHomeTimeLineThread()); } } class HomeAdapter extends BaseAdapter { private Context context; private LayoutInflater inflater; private List<JSONObject> list; public HomeAdapter(Context context, List<JSONObject> list) { super(); this.context = context; this.list = list; this.inflater = LayoutInflater.from(context); } @Override public int getCount() { return list.size(); } @Override public Object getItem(int position) { return list.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(final int position, View convertView, ViewGroup parent) { asyncImageLoader = new AsyncImageLoader(); HomeViewHolder viewHolder = new HomeViewHolder(); JSONObject data = (JSONObject) list.get(position); if(convertView == null){ convertView = inflater.inflate(R.layout.item_user, null); } viewHolder.avatar = (ImageView) convertView .findViewById(R.id.picture); viewHolder.username = (TextView) convertView .findViewById(R.id.username); viewHolder.email = (TextView) convertView.findViewById(R.id.email); if (data != null) { try { viewHolder.username.setText(data.getString("news_title")); viewHolder.email.setText(data.getString("news_content")); // 异步加载图片 Drawable cachedImage = asyncImageLoader.loadDrawable( data.getString("avatar"), viewHolder.avatar, new ImageCallback() { @Override public void imageLoaded(Drawable imageDrawable, ImageView imageView, String imageUrl) { imageView.setImageDrawable(imageDrawable); } }); if (cachedImage == null) { viewHolder.avatar.setImageResource(R.drawable.icon); } else { viewHolder.avatar.setImageDrawable(cachedImage); } } catch (JSONException e) { e.printStackTrace(); } catch (Exception e) { e.printStackTrace(); } } return convertView; } } static class HomeViewHolder { private ImageView avatar; private TextView username; private TextView email; } }