ListView的动态加载效果

 

package com.src.hero;    import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.view.Gravity; import android.view.View; import android.view.ViewGroup; import android.view.ViewGroup.LayoutParams; import android.widget.AbsListView; import android.widget.AbsListView.OnScrollListener; import android.widget.BaseAdapter; import android.widget.LinearLayout; import android.widget.ListView; import android.widget.ProgressBar; import android.widget.TextView; import android.widget.Toast; /**   * @author Hero   * 2012-3-8 下午11:04:21   * 实现动态加载的效果   */ public class DynamicLoadActivity extends Activity {      private ListView lv_main;      private LinearLayout linearlayout = null;      private LayoutParams wlayoutparams, flayoutparams;      listAdapter adpter = null;      Thread thread;         /** Called when the activity is first created. */      @Override      public void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.main);          lv_main = (ListView) findViewById(R.id.listView1);          adpter = new listAdapter(this);          wlayoutparams = new LinearLayout.LayoutParams(320, 50);// 定义的是FootView的宽高          flayoutparams = new LinearLayout.LayoutParams(                  LinearLayout.LayoutParams.WRAP_CONTENT,                  LinearLayout.LayoutParams.WRAP_CONTENT);// 定义FootView中控件的布局          ProgressBar progressbar = new ProgressBar(this);// 定义一个ProgressBar          progressbar.setPadding(50, 0, 0, 0);// left, top, right, bottom          TextView tv_wait = new TextView(this);// 定义一个TextView          tv_wait.setText("正在动态加载……");          tv_wait.setTextSize(20f);          tv_wait.setGravity(Gravity.CENTER_VERTICAL);          tv_wait.setPadding(10, 0, 0, 0);          LinearLayout layout = new LinearLayout(this);          layout.setOrientation(LinearLayout.HORIZONTAL);          layout.addView(progressbar, flayoutparams);          layout.addView(tv_wait, flayoutparams);          layout.setGravity(Gravity.CENTER);          linearlayout = new LinearLayout(this);          linearlayout.addView(layout, wlayoutparams);          linearlayout.setGravity(Gravity.CENTER_VERTICAL);          lv_main.addFooterView(linearlayout);          lv_main.setAdapter(adpter);          lv_main.setOnScrollListener(scroller);      }      /**       * 滚动监听器       */      OnScrollListener scroller = new OnScrollListener() {          @Override          public void onScroll(AbsListView view, int firstVisibleItem,                  int visibleItemCount, int totalItemCount) {              // TODO Auto-generated method stub              if (firstVisibleItem + visibleItemCount == totalItemCount) {                  // 启动一个线程去加载网络数据                  if (thread == null || !thread.isAlive()) {                      thread = new Thread() {                          @Override                          public void run() {                              try {                                  // 处理网络方法,在这里用线程休眠3秒方法来处理                                  Thread.sleep(3000);                              } catch (InterruptedException e) {                                  e.printStackTrace();                              }                              Message message = new Message();                              message.what = 1;                              handler.sendMessage(message);                          }                      };                      thread.start();                  }              }          }             @Override          public void onScrollStateChanged(AbsListView view, int scrollState) {              // TODO Auto-generated method stub             }         };      /**       * 消息队列       */      private Handler handler = new Handler() {          @Override          public void handleMessage(Message msg) {              // TODO Auto-generated method stub              switch (msg.what) {              case 1:                  if (adpter.count <= 101) {                      adpter.count += 10;                      int currentPage = adpter.count / 10;                      Toast.makeText(getApplicationContext(),                              "第" + currentPage + "页", Toast.LENGTH_LONG).show();                  } else {                      lv_main.removeFooterView(linearlayout);                  }                  // 重新刷新Listview的adapter里面数据                  adpter.notifyDataSetChanged();                  break;              default:                  break;              }          }      };         public class listAdapter extends BaseAdapter {             int count = 10;          Context context;             public listAdapter(Context context) {              this.context = context;          }             @Override          public int getCount() {              // TODO Auto-generated method stub              return count;          }             @Override          public Object getItem(int position) {              // TODO Auto-generated method stub              return position;          }             @Override          public long getItemId(int item) {              // TODO Auto-generated method stub              return item;          }             @Override          public View getView(int position, View convertView, ViewGroup parent) {              // TODO Auto-generated method stub              TextView tv_content;              if (convertView == null) {                  tv_content = new TextView(context);              } else {                  tv_content = (TextView) convertView;              }              tv_content.setText("Item     " + position);              tv_content.setTextSize(20f);//字体的大小20f              tv_content.setGravity(Gravity.CENTER);//显示在中间              tv_content.setHeight(50);//高度为50              return tv_content;          }         } }