小编Tur*_*1ng的帖子

我正在为我的新项目使用android房间持久性库.我想更新一些表的字段.我试过像我一样Dao-

// Method 1:

@Dao
public interface TourDao {
    @Update
    int updateTour(Tour tour);
}

但是当我尝试使用此方法进行更新时,它会更新实体中与tour对象的主键值匹配的每个字段.我用过@Query

// Method 2:

@Query("UPDATE Tour SET endAddress = :end_address WHERE id = :tid")
int updateTour(long tid, String end_address);

它正在工作,但在我的案例中会有很多查询,因为我的实体中有很多字段.我想知道如何更新某些字段(不是全部),例如Method 1id = 1; (id是自动生成主键).

// Entity:

@Entity
public class Tour {
    @PrimaryKey(autoGenerate = true)
    public long id;
    private String startAddress;
    private String endAddress;
    //constructor, getter and setter
}

我创建了一个Contentprovide并实现了它的update()方法,如下所示:

@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appwidget中收到通知？谢谢!

我正在尝试这个解析器,但没有Log(-------------------- Date Changed)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.

        // …

我每天都会重复闹钟.但它会有几秒或几分钟的错误.我怎样才能让它更准确？

PendingIntent pendingIntent = PendingIntent.getBroadcast(getActivity(), notificationId, myIntent, PendingIntent.FLAG_UPDATE_CURRENT);
AlarmManager alarmManager = (AlarmManager)getActivity().getSystemService(Context.ALARM_SERVICE);
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 12);
calendar.set(Calendar.MINUTE, 30);
long startUpTime = calendar.getTimeInMillis();
if (System.currentTimeMillis() > startUpTime) {
    startUpTime = startUpTime + 24*60*60*1000;
}
alarmManager.setRepeating(AlarmManager.RTC_WAKEUP, startUpTime,  24*60*60*1000 , pendingIntent);