以下代码是从实际项开发开代码分离出来的示例，你要明确一点，就是Service在不断的更新数据，这里只是对绑定了Adapter，并注册了ContentObserver。这里有两个同步渲染点。

由ContentObserver自行触发的
由Layout中的refresh按钮触发的


package cn.lifedu.lifebox;

import cn.lifedu.lifebox.LifeboxMetaData.FeedMetaData;
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.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class FeedActivity extends Activity {
	
	private class FeedObserver extends ContentObserver {

		public FeedObserver(Handler handler) {
			super(handler);
			// TODO Auto-generated constructor stub
		}
		
		@Override
		public void onChange(boolean change){
			super.onChange(change);
			if(pc.isClosed()){
				return;
			}
			pc.requery();
			pfa.notifyDataSetChanged();
			Toast.makeText(getApplicationContext(), "observer refresh", Toast.LENGTH_LONG).show();
		}

	}

	public static FeedAdapter pfa;
	public static Cursor pc;
	
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.feed);
		
		TextView tv = (TextView)findViewById(R.id.textView1);
		tv.setText("Feed");
		
		ListView lv = (ListView)findViewById(R.id.listView1);
		
		ContentResolver cr = getContentResolver();
		Cursor c = cr.query(FeedMetaData.CONTENT_URI,null,null,null,null);
		FeedAdapter fa = new FeedAdapter(this,c);
		c.registerContentObserver(new FeedObserver(new Handler()));
		pfa = fa;
		pc = c;
		
		Button btn = (Button)findViewById(R.id.refresh);
		
		btn.setOnClickListener(new OnClickListener(){
			
			public void onClick(View v) {
				// TODO Auto-generated method stub
				if(FeedActivity.pc.requery()){
					FeedActivity.pfa.notifyDataSetChanged();
					Toast.makeText(getApplicationContext(), "refresh", Toast.LENGTH_LONG).show();
				}else{
					Toast.makeText(getApplicationContext(), "no refresh", Toast.LENGTH_LONG).show();
				}
			}
		});
		
		
		lv.setAdapter(fa);
		
	}
}