如何观察内容提供者的变化？安卓

概述我创建了一个Contentprovide,并实现了这样的update()方法： @Override public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) { final SQLiteDatabase db = mHelper.getWr 我创建了一个ContentprovIDe,并实现了这样的update()方法：

@OverrIDe   public int update(Uri uri,ContentValues values,String selection,String[] selectionArgs) {      final sqliteDatabase db = mHelper.getWritableDatabase();      int count = db.update(InslIDeDB.FolDER_table,values,selection,selectionArgs);      /* To notify the observer */      this.getContext().getContentResolver().notifyChange(URI,null);        return count;}

如何在我的appWidget中获得通知？谢谢！

我正在尝试这个Resolver,但没有日志(——————–更改日期)打印：

class DataProvIDerObserver extends ContentObserver {    private AppWidgetManager mAppWidgetManager;    private Componentname mComponentname;    DataProvIDerObserver(AppWidgetManager mgr,Componentname cn,Handler h) {        super(h);        mAppWidgetManager = mgr;        mComponentname = cn;    }    @OverrIDe    public voID onChange(boolean selfChange) {        super.onChange(selfChange);  //NOTE: Have to call this. DWy.        // The data has changed,so notify the Widget that the collection vIEw needs to be updated.        // In response,the factory's onDataSetChanged() will be called which will requery the        // cursor for the new data.        Log.d("PresenterWidgetProvIDer","--------------------Date Changed");        mAppWidgetManager.notifyAppWidgetVIEwDataChanged(                mAppWidgetManager.getAppWidgetIDs(mComponentname),R.ID.inslIDe_grID);    }}public class PresenterWidgetProvIDer extends appwidgetprovider{    private static final String AUTHORITY = "com.apps.slIDe";    static final Uri CONTENT_URI = Uri.parse("content://" + AUTHORITY + "/folder");    public static final String EXTRA_INSLIDE_PATH = "EXTRA_Widget_PATH";    private static HandlerThread sWorkerThread;    private static Handler sWorkerQueue;    private static DataProvIDerObserver sDataObserver;    public PresenterWidgetProvIDer () {        // Start the worker thread to update Content ProvIDer.        sWorkerThread = new HandlerThread("PresenterWidgetProvIDer worker");        sWorkerThread.start();        sWorkerQueue = new Handler(sWorkerThread.getLooper());    }    @OverrIDe    public voID onEnabled(Context context) {        // Register for external updates to the data to trigger an update of the Widget.  When using        // content provIDers,the data is often updated via a background service,or in response to        // user interaction in the main app.  To ensure that the Widget always reflects the current        // state of the data,we must Listen for changes and update ourselves accordingly.        final ContentResolver r = context.getContentResolver();        if (sDataObserver == null) {            final AppWidgetManager mgr = AppWidgetManager.getInstance(context);            final Componentname cn = new Componentname(context,PresenterWidgetProvIDer.class);            sDataObserver = new DataProvIDerObserver(mgr,cn,sWorkerQueue);            r.registerContentObserver(CONTENT_URI,true,sDataObserver);            Log.d("PresenterWidgetProvIDer","--------------------onEnabled. sDataObserver = " + sDataObserver);        }    }

所以,我终于通过4个步骤解决了：

>添加
this.getContext().getContentResolver().notifyChange(URI,null);

到ContentProvIDer的updat()insert()delete()回调.

>创建一个新的观察者和新的线程来处理它.
>在Observer的onChange()中调用notifyAppWidgetVIEwDataChanged().
>删除小部件并放置一个新的.

而已.

解决方法 您可以使用 ContentObserver类.您只需要实现该类,并使用getContentResolver().registerContentObserver()方法来注册观察者. 总结

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