Question

我目前正在开发一款应用程序，即家庭视图控制器显示所有用户朋友，他们的名字和他们的个人资料图片（如果他们有一个）的显示，每个都在UICollectionView的单元格内。我使用标签来识别每个单元格中的UI元素，并使用Parse作为后端。每个用户及其关系都存储在班级＆＃34;用户＆＃34;然后他们的个人资料图片（如果他们选择了一个/一个）存储在另一个名为＆＃34; UserImage＆＃34;的类中。我设法将他们的用户名设置为单元格但是图像有困难。基本上每个单元格都在下载整个图像阵列，我认为这会导致应用程序因此错误而崩溃。此外，一旦用户添加没有个人资料图片的朋友，该应用程序似乎行为奇怪..

[__NSArrayM objectAtIndex:]: index 8 beyond bounds [0 .. 1]

这是我如何保存图像以解析..这是在用户配置文件视图控制器中。

-(void)uploadImage {

    NSData *fileData;
    NSString *fileName;
    NSString *fileType;

    UIImage *newImage = [self scaleImage:self.image toSize:CGSizeMake(340.0,340.0)];
    fileData = UIImagePNGRepresentation(newImage);
    fileName = @"profileimage.png";
    fileType = @"profileimage";

    PFFile *file = [PFFile fileWithName:fileName data:fileData];

    [file saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {

        PFUser *user = [PFUser currentUser];
        PFObject *userImage = [PFObject objectWithClassName:@"UserImage"];

        [userImage setObject:file forKey:@"file"];
        [userImage setObject:fileType forKey:@"fileType"];
        [userImage setObject:user forKey:@"user"];
        [userImage saveInBackgroundWithBlock:^(BOOL succeeded, NSError *error) {
            if (error) {
                NSLog(@"Error saving image");
            }
            else {
                NSLog(@"Image Saved");
            }
        }];
    }];

}

然后我在HomeViewController的 viewWillAppear：方法中查询当前用户关系。

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];

    [self.navigationController.navigationBar setHidden:NO];

    self.friendsRelation = [[PFUser currentUser] objectForKey:@"friendsRelation"];

    self.friends = [[NSMutableArray alloc] init];

    PFQuery *query = [self.friendsRelation query];
    [query orderByAscending:@"username"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (error) {
            NSLog(@"Error %@ %@", error, [error userInfo]);
        }
        else {
            [self.friends addObjectsFromArray:objects];
            [self.collectionView reloadData];
        }
    }];
}

将单元格数量设置为用户朋友的数量..

- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{
    return [self.friends count];
}

最后在 cellForItemAtIndexPath：方法中设置单元格

- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{
    static NSString *identifier = @"Cell";

    UICollectionViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:identifier forIndexPath:indexPath];

    PFUser *user = [self.friends objectAtIndex:indexPath.row];

    if (cell.tag == 0) {

        UILabel *cellLabel = (UILabel *)[cell viewWithTag:25];
        cellLabel.text = user.username;

        PFImageView *homeImageView = (PFImageView *)[cell viewWithTag:50];
        [homeImageView setContentMode:UIViewContentModeScaleAspectFill];
        homeImageView.clipsToBounds = YES;
        homeImageView.layer.cornerRadius = 7;

        self.friendImages = [[NSMutableArray alloc] init];

        PFQuery *imageQuery = [PFQuery queryWithClassName:@"UserImage"];
        [imageQuery whereKey:@"user" containedIn:self.friends];
        [imageQuery findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
            if (!error) {

                //need a statement that defines whether a friend has an image or not, if they do then load that image into their cell, if not then set default image

                [self.friendImages addObjectsFromArray:objects];
                PFObject *imageObject = [self.friendImages objectAtIndex:indexPath.row];
                PFFile *imageFile = [imageObject objectForKey:@"file"];
                homeImageView.file = imageFile;
                [homeImageView loadInBackground];

                NSLog(@"Retrieved %d images", [self.friendImages count]);
            }
            else {
                NSLog(@"Error: %@ %@", error, [error userInfo]); 
            }

        }];

    return cell;
}

任何帮助将不胜感激！请记住，我只需要几周的时间来学习iOS ..

如何将图像数组放入特定的UICollectionViewCells

0 个答案: