Question

我对如何从选定的行获取特定列感到困惑。

我的第一个View是一个UICollectionView，它可以查找Class中的所有对象。选择一个单元格后，您将被一个包含另一个UICollectionView的DetailView拦截，该另一个UICollectionView将显示该选定行的文件。

如何设置查询以便第二个CollectionView显示特定行的特定列？

请看图片。我需要在第二个CollectionView中显示image_1，image_2，image_3 ......等等。

My Data Browser

已编辑代码：

VestimentaViewController.m

#import "VestimentaViewController.h"
#import "VestimentaDetailViewController.h"

@interface VestimentaViewController ()

@end

@implementation VestimentaViewController

@synthesize imagesCollection, activityIndicator;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
    // Custom initialization
}
return self;
}

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.

[self queryParseMethod];

}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}


- (void)queryParseMethod {

[activityIndicator startAnimating];

PFQuery *query = [PFQuery queryWithClassName:@"VestimentaView"];

[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {
        vestimentaFilesArray = [[NSArray alloc] initWithArray:objects];

        [imagesCollection reloadData];
    }


}];
}

#pragma mark Collection data source

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {

return 1;

}

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:    (NSInteger)section {

return [vestimentaFilesArray count];

}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView  cellForItemAtIndexPath:(NSIndexPath *)indexPath {

static NSString *cellIdentifier = @"Cell";
VestimentaCell *cell = (VestimentaCell *) [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];

PFObject *infoObject = [vestimentaFilesArray objectAtIndex:indexPath.row];

cell.storeName.text = [infoObject objectForKey:@"cellTitle"];

cell.storeDescription.text = [infoObject objectForKey:@"descriptionTitle"];

[activityIndicator stopAnimating];

    }

return cell;

}


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

    NSIndexPath *indexPath = [self.imagesCollection indexPathForCell:sender];

    PFObject *object = [vestimentaFilesArray objectAtIndex:indexPath.item];

    VestimentaDetailViewController *detailViewController = segue.destinationViewController;

    detailViewController.vestimenta = object;
}
}


@end

VestimentaViewController.h

#import <UIKit/UIKit.h>
#import "VestimentaCell.h"
#import <Parse/Parse.h>


@interface VestimentaViewController : UIViewController {

NSArray *vestimentaFilesArray;
NSMutableArray *tiendasArray;
}

@property (weak, nonatomic) IBOutlet UICollectionView *imagesCollection;
@property (weak, nonatomic) IBOutlet UIActivityIndicatorView *activityIndicator;

@end

VestimentaDetailViewController.m

#import "VestimentaDetailViewController.h"
#import "VestimentaViewController.h"


@interface VestimentaDetailViewController ()

@end

@implementation VestimentaDetailViewController

@synthesize imagesCollection;


- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
    // Custom initialization
}
return self;
}

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.

[self queryParseMethod];

}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

#pragma mark Collection data source

-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView {

return 1;

}

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {

return [filesArray count];

}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath {

static NSString *cellIdentifier = @"Cell";
VestimentaDetailCell *cell = (VestimentaDetailCell *) [collectionView dequeueReusableCellWithReuseIdentifier:cellIdentifier forIndexPath:indexPath];

PFFile *imageFile = [self.vestimenta objectForKey:@"image_1"];

[imageFile getDataInBackgroundWithBlock:^(NSData *data, NSError *error) {
if (!error) {
cell.imageFile.image = [UIImage imageWithData:data];

}
}];

return cell;

}

@end

VestimentaDetailViewController.h

#import <UIKit/UIKit.h>
#import "VestimentaDetailCell.h"
#import <Parse/Parse.h>


@interface VestimentaDetailViewController : UIViewController {

NSArray *filesArray;

}

@property (weak, nonatomic) PFObject *vestimenta;

@property (weak, nonatomic) IBOutlet UICollectionView *imagesCollection;

@end

这将显示每个单元格的图像Clicked但仅显示image_1 ...如何构建将显示任何单击单元格的image_1，image_2，image_3的数组或字典（在第二个或详细视图控制器中）？

Answer 1

您可以编写一个函数，该函数在选择行时调用，该函数将触发查询并在第二个ViewController中放置在imageview（PFImageView）上，如

-(void)settingAllImageView
{
 PFQuery *query = [PFQuery queryWithClassName:@"ImageClassName"];

 /*Could put up condition if require specific row*/

 [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error)
 {
     if (!error && objects.count != 0)
     {
         NSLog(@"Successfully retrieved: %@", objects);

         for(int *i=0;i<=[objects count];i--)
         {
           NSDictionary *dict = [objects objectAtIndex:i];
           PFFile *file = [object objectForKey:@"image"];
           imageView.file = file;
           /*imageView is  PFImageView*/

           /*For more than 1 images in a row you could store PFFiles in a array den use that array to load up imageView*/
         }      

   // Now tell PFImageView to download the file asynchronously
   [imageView loadInBackground];
  }
 }];
}

Answer 2

您不从Parse获取特定列。您始终将整行作为PFObject获取，然后从该对象获取特定属性。

在您的集合视图中，您已经显示了cellTitle。这意味着您已经拥有包含图像的PFObject。您应该使用PFImageView来显示图像。这些文件尚未下载，因此您需要做的是将PFImageView文件设置为image_1文件等，如下所示：

PFImageView *firstImage = [[PFImageView alloc] init];
firstImage.file = theObjectFromPreviousCollectionView[@"image_1"];
[firstImage loadInBackground];

“theObjectFromPreviousCollectionView”是与您单击的单元格对应的对象。在prepareForSegue方法中，将此对象传递给详细信息视图。

从Parse.com获取特定文件

2 个答案: