Question

我通过填充“imageFilesArray”并告诉UICollectionViewCells使用其数据来加载“Rooms”UICollectionView，其中包含登录用户在之前的视图控制器中选择的特定图像：

-(void) retrieveSelectedImagesForRooms
{
//parse query where we search the selectedImage array column and return any entry where the array contains the logged in user objectid

   PFQuery *getRooms = [PFQuery queryWithClassName:@"collectionViewData"];
   [getRooms whereKey:@"selectedImage" equalTo:[PFUser currentUser].objectId];

   [getRooms findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error)
    {
        imageFilesArray = [[NSArray alloc] initWithArray:objects];
        [roomsCollection reloadData];
    }
}];
}

下一页必须显示用户为之前选择的房间图像选择的特定灯光。因此，当我选择房间时，我将刚刚选择的行的目标添加到Parse上的新列，名为“clickedRoom”：

-(void)selectedRoom:(PFObject*)object
{
    [object addUniqueObject:object.objectId forKey:@"clickedRoom"]; //put object id into clickedRoom column on Parse to save what room you specifically chose so that the light images correspond to only that room

    [object saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error)
    {
    if (!error){}
    else{}
}];
}


- (void)collectionView:(UICollectionView*)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {

   [self selectedRoom:[imageFilesArray objectAtIndex:indexPath.row]];
   [self performSegueWithIdentifier:@"myLights" sender:self];

}

现在，在“灯光”页面中，我只需要在“clickedRoom”列中显示具有所选房间的光照图像。我相信它与我如何检索房间图像的原理相同，但我无法弄清楚我应该查询的内容，例如：

-(void) retrieveCorrespondingImagesForLights
{
   PFQuery *getLights = [PFQuery queryWithClassName:@"collectionViewData"];
   [getLights whereKey:@"clickedRoom" equalTo:**MY-PREVIOUSLY-SELECTED-ROW**.objectid];
   [getLights findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error)
    {
        imageFilesArray = [[NSArray alloc] initWithArray:objects];
        [myLightsCollection reloadData];
    }
}];

}

有什么建议吗？！

Answer 1

retrieveCorrespondingImagesForLights与您的roomsCollection在不同的视图控制器中，对吗？如果是这样，那么您将需要将所选房间的对象ID传递给在[self performSegueWithIdentifier:@"myLights" sender:self];

处进行伪装的新视图控制器

看看Pass Index Number between UITableView List segue

在您的情况下，您应该向目标视图控制器添加一个属性（我称之为LightsViewController）以捕获对象，或者如果查询需要的话，则为objectId。我会建议这样的事情：

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{   
  if ([segue.identifier isEqualToString:@"myLights"]) {

    // note that "sender" will be the cell that was selected
    UICollectionViewCell *cell = (UICollectionViewCell*)sender;
    NSIndexPath *indexPath = [roomsCollection indexPathForCell:cell];

    LightsViewController *vc = (LightsViewController*)[segue destinationViewController];
    vc.selectedObject = indexPath.row;
  }
}

然后，在retrieveCorrespondingImagesForLights：

中

PFQuery *getLights = [PFQuery queryWithClassName:@"collectionViewData"];
[getLights whereKey:@"clickedRoom" equalTo:self.selectedObject.objectid];

编辑*

如果您不了解确切的实施细节，那么您似乎正在尝试使用Parse在您的视图控制器之间传递数据，而您更适合在应用中本地执行此操作。也许我误解了你的问题。

如何从Parse.com检索某些图像

1 个答案: