android下内容观察者: ContentObserver

public class MainActivity extends Activity {

      private SmsInfoBean  smsBean;

      private TextView      tv ;

      

      @Override

      protected void onCreate(Bundle savedInstanceState) {

             super.onCreate(savedInstanceState);

            setContentView(R.layout. activity_main);

            

             tv=( TextView) findViewById(R.id.tv);

            

             //获取内容解析者

            ContentResolver resolver = getContentResolver();

            

             //调用内容观察者: 1.关心的数据的路径      2.路径条件满足时   3.内容观察者(观察数据:改变时告诉你)

            resolver.registerContentObserver(Uri. parse("content://sms/"), true, new Myobserver( new Handler()));

            

            

            

      }

      

      /**

       * 创建内容观察者

       * @author Administrator

       *

       */

      private class Myobserver  extends ContentObserver{

             public Myobserver(Handler handler) {

                   super(handler);

                  

            }

            

            

             /**

             * 内容观察者观察数据变化时调用

             */

        @Override

             public void onChange( boolean selfChange) {

                   super.onChange(selfChange);

                    //读取短信记录

                    Cursor cursor = getContentResolver().query(Uri.parse( "content://sms/"), new String[]{"address","body" ,"date" }, null, null, null);

                   

                    cursor.moveToFirst();

                    String address = cursor.getString(cursor.getColumnIndex("address" ));

                    String body = cursor.getString(cursor.getColumnIndex("body" ));

                    String date = cursor.getString(cursor.getColumnIndex("date" ));

                   

                    smsBean= new SmsInfoBean();

                    smsBean.setAddress(address);

                    smsBean.setBody(body);

                    smsBean.setDate(date);

                   

                    tv.setText( smsBean.toString());

                   

            }

            

            

            

            

            

            

      }

      

 }

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// 注册ContentObserver监听ContentProvider中的数据修改, 当数据被修改的时候, 重新查询数据库, 刷新界面

            getContentResolver().registerContentObserver(Uri. parse("content://ItheimaProvider"), true, newMyObserver());

      }

      

      private class MyObserver extends ContentObserver {

             public MyObserver() {

                   super( new Handler());                                  // 处理器, 用来做线程之间的通信

            }

             public void onChange( boolean selfChange) {             // 当收到数据修改通知时, 调用这里

                   list = dao.queryAll();

                   adapter.notifyDataSetChanged();

            }

      }