ContentObserver的使用类似与设计模式中的观察者模式，ContentObserver是观察者，被观察的ContentProvider是被观察者。当被观察者ContentProvider的数据发生了增删改的变化，就会及时的通知给ContentProvider，ContentObsserver做出相应的处理。

package com.example.android_contentobserver;

import android.app.Activity;

import android.database.ContentObserver;

import android.database.Cursor;

import android.net.Uri;

import android.os.Bundle;

import android.os.Handler;

public class MainActivity extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

//注册观察者Observser

this.getContentResolver().registerContentObserver(Uri.parse("content://sms"),true,new SMSObserver(new Handler()));

}

private final class SMSObserver extends ContentObserver {

public SMSObserver(Handler handler) {

super(handler);

}

@Override

public void onChange(boolean selfChange) {

Cursor cursor = MainActivity.this.getContentResolver().query(

Uri.parse("content://sms/inbox"), null, null, null, null);

while (cursor.moveToNext()) {

StringBuilder sb = new StringBuilder();

sb.append("address=").append(

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

sb.append(";subject=").append(

cursor.getString(cursor.getColumnIndex("subject")));

sb.append(";body=").append(

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

sb.append(";time=").append(

cursor.getLong(cursor.getColumnIndex("date")));

System.out.println("--------has Receivered SMS::" + sb.toString());

}

}

}

}