Android实现静态广播监听器的方法

本文实例讲述了android实现静态广播监听器的方法。分享给大家供大家参考。具体实现方法如下：

package lab.sodino.broadcastaction;
import lab.sodino.util.databaseopenhelper;
import lab.sodino.util.sodinoout;
import android.app.activity;
import android.content.contentresolver;
import android.database.contentobserver;
import android.database.cursor;
import android.os.bundle;
import android.os.handler;
import android.os.message;
import android.view.view;
import android.view.viewgroup.layoutparams;
import android.widget.button;
import android.widget.linearlayout;
import android.widget.scrollview;
import android.widget.textview;
/**
 * 本例子将记录可静态注册的广播被监听到的频度。<br/>
 * 1.建立一表{action_name广播名称,last_time最近一次发生时间,count总共记录到的次数}<br/>
 * 2.在actionreceiver中监听广播，并记录。 <br/>
 * 3.在dbcontentprovider中更新数据库记录<br/>
 * 4.在broadcastactionrecordact.actiondbobserver中监听数据库的变化，
 * 并使用handler机制将最新情况显示在txtinfo上。<br/>
 * 5.databaseopenhelper将实现基本的数据库操作。
 * 
 * @author sodino
 */
public class broadcastactionrecordact extends activity implements
  button.onclicklistener {
 private textview txtinfo;
 private databaseopenhelper dbhelper;
 private button btnrefresh;
 /** clear功能未完善。 */
 private button btnclear;
 private handler handler = new handler() {
  public void handlemessage(message msg) {
   string info = (string) msg.obj;
   txtinfo.settext(info);
  }
 };
 @override
 public void oncreate(bundle savedinstancestate) {
  super.oncreate(savedinstancestate);
  layoutparams lppc = new layoutparams(layoutparams.fill_parent,
    layoutparams.wrap_content);
  layoutparams lpcc = new layoutparams(layoutparams.wrap_content,
    layoutparams.wrap_content);
  btnrefresh = new button(this);
  btnrefresh.setlayoutparams(lpcc);
  btnrefresh.settext("refresh");
  btnrefresh.setonclicklistener(this);
  btnclear = new button(this);
  btnclear.setlayoutparams(lpcc);
  btnclear.settext("cleartable");
  btnclear.setonclicklistener(this);
  linearlayout sublayout = new linearlayout(this);
  sublayout.setlayoutparams(lppc);
  sublayout.setorientation(linearlayout.horizontal);
  sublayout.addview(btnrefresh);
  sublayout.addview(btnclear);
  txtinfo = new textview(this);
  txtinfo.setlayoutparams(lppc);
  txtinfo.settextcolor(0xff0000ff);
  txtinfo.setbackgroundcolor(0xffffffff);
  txtinfo.settext("starting...");
  txtinfo.settextsize(15);
  scrollview scrollview = new scrollview(this);
  scrollview.setlayoutparams(lppc);
  scrollview.addview(txtinfo);
  linearlayout mainlayout = new linearlayout(this);
  mainlayout.setlayoutparams(lppc);
  mainlayout.setorientation(linearlayout.vertical);
  mainlayout.addview(sublayout);
  mainlayout.addview(scrollview);
  setcontentview(mainlayout);
  dbhelper = new databaseopenhelper(this);
  contentresolver contentresolver = getcontentresolver();
  contentresolver.registercontentobserver(dbcontentprovider.content_uri,
    false, new actiondbobserver(handler));
 }
 public void onclick(view view) {
  if (view == btnrefresh) {
   refreshrecord();
  } else if (view == btnclear) {
   clearrecord();
  }
 }
 public void refreshrecord() {
  dbhelper.openreadabledatabase();
  string info = dbhelper.getallorderedlist(databaseopenhelper.desc);
  dbhelper.close();
  if (info != null) {
   txtinfo.settext(info);
  } else {
   txtinfo.settext("<null/>");
  }
  dbhelper.close();
 }
 public void clearrecord() {
  dbhelper.openwritabledatabase();
  dbhelper.clearrecord();
  dbhelper.close();
 }
 private class actiondbobserver extends contentobserver {
  private handler handler;
  public actiondbobserver(handler handler) {
   super(handler);
   this.handler = handler;
  }
  public void onchange(boolean selfchange) {
   super.onchange(selfchange);
   string[] projection = { "action_name", "last_time", "count" };
   // string selection = "select * from actiontable";
   string sortorder = "count desc";
   // dbhelper.openreadabledatabase();
   // cursor cursor = dbhelper.query(projection, null, null,
   // sortorder);
   cursor cursor = managedquery(dbcontentprovider.content_uri,
     projection, null, null, sortorder);
   string info = "";
   string line = "";
   int actionidx = 0;
   int timeidx = 1;
   int countidx = 2;
   while (cursor.movetonext()) {
    line += cursor.getstring(actionidx) + " ";
    line += cursor.getstring(timeidx) + " ";
    line += cursor.getstring(countidx) + "/n";
    info += line;
    line = "";
   }
   message msg = new message();
   msg.obj = info;
   handler.sendmessage(msg);
   cursor.close();
   // dbhelper.close();
   sodinoout.out("database does changed!!!");
  }
  public boolean deliverselfnotifications() {
   return super.deliverselfnotifications();
  }
 }
}

希望本文所述对大家的android程序设计有所帮助。