Loading imageviews with AFNetworking via JSON hierarchy and objectForKey

问题

Very new to AFNetworking, but after many SO questions... I've concluded that this is the solution to my issue.

I've got a hierarchy of JSON data loading my TableViewController cells dynamically. All of my text strings are loading appropriately but the image from my URL is not making it to my imageview.

Before utilizing the AFNetworking library, I had the images loaded, but I was experiencing some issues with the photos not staying loaded when I scrolled away and returned (they had to load again.)

What am I missing to get my images in there?

TableViewController.m

-(void)viewDidLoad {
    [super viewDidLoad];

    // Set the side bar button action. When it's tapped, it'll show up the sidebar.
    siderbarButton.target = self.revealViewController;
    siderbarButton.action = @selector(revealToggle:);

    // Set the gesture
    [self.view addGestureRecognizer:self.revealViewController.panGestureRecognizer];

    self.tableView.backgroundColor = [UIColor whiteColor];
    self.parentViewController.view.backgroundColor = [UIColor colorWithRed:1.0 green:1.0 blue:1.0 alpha:1];

    self.navigationItem.titleView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"logo_app_white.png"]];

    NSURL *myURL = [[NSURL alloc]initWithString:@"http://domain.com/json2.php"];
    NSData *myData = [[NSData alloc]initWithContentsOfURL:myURL];
    NSError *error;

    jsonArray = [NSJSONSerialization JSONObjectWithData:myData options:NSJSONReadingMutableContainers error:&error];

    [tableView reloadData]; // if tableView is unidentified make the tableView IBOutlet
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.
    return jsonArray.count;
}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

    NeedCardTableViewCell *cell = (NeedCardTableViewCell *) [tableView dequeueReusableCellWithIdentifier:@"needCard"];

    if (cell == nil)
    {
        cell = [[NeedCardTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"needCard"];
    }

    NSDictionary *needs = jsonArray[indexPath.row]; // get the data dict for the row
    cell.textNeedTitle.text = [needs objectForKey: @"needTitle"];
    cell.textNeedPoster.text = [needs objectForKey: @"needPoster"];
    cell.textNeedDescrip.text = [needs objectForKey: @"needDescrip"];

    AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
    [manager GET:@"userImage" parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
        NSLog(@"JSON: %@", responseObject);
        _imageProfPic.image = responseObject;
    } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
        NSLog(@"Error: %@", error);
    }];

    return cell;
}

回答1:

Have you tried using the AFNetworking+UIImageView category? You can then call:

[_imageProfPic setImage:[NSURL URLWithString:@"http://myimageurl.com/imagename.jpg"]];

This will make a request and then set the returned image to your UIImageView's UIImage without you having to do anything else. You should also consider initializing NSURLCache in your AppDelegate:

NSURLCache *cache = [[NSURLCache alloc] initWithMemoryCapacity:4 * 1024 * 1024
                                                  diskCapacity:10 * 1024 * 1024
                                                      diskPath:nil];
[NSURLCache setSharedURLCache:cache];

Take a look at NSHipster's run down on NSURLCache. This will help reload images, and all your requests, much faster the second time around. This is increasingly important when dealing with images and tables.

回答2:

Manage to figure this one out with the use of this tutorial: Networking Made Easy with AFNetworking

I used the final snippet of code to get my desired result:

NSURL *url = [[NSURL alloc] initWithString:[movie objectForKey:@"artworkUrl100"]];
[cell.imageView setImageWithURL:url placeholderImage:[UIImage imageNamed:@"placeholder"]];

I cut the second line of his code because I already have an if statement in my PHP/JSON

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{

    NeedCardTableViewCell *cell = (NeedCardTableViewCell *) [tableView dequeueReusableCellWithIdentifier:@"needCard"];

    if (cell == nil)
    {
        cell = [[NeedCardTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"needCard"];
    }

    NSDictionary *needs = jsonArray[indexPath.row]; // get the data dict for the row
    cell.textNeedTitle.text = [needs objectForKey: @"needTitle"];
    cell.textNeedPoster.text = [needs objectForKey: @"needPoster"];
    cell.textNeedDescrip.text = [needs objectForKey: @"needDescrip"];

    NSURL *url = [[NSURL alloc] initWithString:[needs objectForKey:@"userImage"]];
    [cell.imageProfPic setImageWithURL:url];

    return cell;
}

It worked like a charm, and the tutorial was pretty helpful since I'm a rookie with AFNetworking.

来源：https://stackoverflow.com/questions/23122654/loading-imageviews-with-afnetworking-via-json-hierarchy-and-objectforkey