监测database的改变--notifyChange
我们在ContentProvider的insert,update,delete等改变之后调用getContext().getContentResolver().notifyChange(uri, null);这样就通知那些监测databases变化的observer了，而你的observer可以在一个service里面注册。
以Downloadmanger为例子：
定义ContentObserver，并且在onChange里做你想做的事情。
/** * Receives notifications when the data in the content provider changes */ private class DownloadManagerContentObserver extends ContentObserver { public DownloadManagerContentObserver() { super(new Handler()); } /** * Receives notification when the data in the observed content * provider changes. */ public void onChange(final boolean selfChange) { if (Constants.LOGVV) { Log.v(Constants.TAG, "Service ContentObserver received notification"); } updateFromProvider(); } } public void onCreate() { super.onCreate(); if (Constants.LOGVV) { Log.v(Constants.TAG, "Service onCreate"); } mDownloads = Lists.newArrayList(); mObserver = new DownloadManagerContentObserver(); getContentResolver().registerContentObserver(Downloads.CONTENT_URI, true, mObserver);......} /** * Cleans up when the service is destroyed */ public void onDestroy() { getContentResolver().unregisterContentObserver(mObserver); if (Constants.LOGVV) { Log.v(Constants.TAG, "Service onDestroy"); } super.onDestroy(); }