How to set image path coming from server in uitableviewcell - ios

Question

I am making an app in which i am getting data from server and in data image path is also coming but when i am setting image to my tableview cell app will become too much heavy may b i am not setting image properly below is my sample code thanx in advance :)
(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString *tableviewidentifier = #"cell";
tablecellTableViewCell *cell= [self.activitiesTableView_ dequeueReusableCellWithIdentifier:tableviewidentifier];
if(cell==nil)
{
cell = [[tablecellTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:tableviewidentifier];
}if(indexPath.row == [self tableView:tableView numberOfRowsInSection:indexPath.section] - 1){
// [[cell textLabel] setText:#"Load more records"];
}
UILabel *valuedate = (UILabel *)[cell viewWithTag:21];
UILabel *msg = (UILabel *)[cell viewWithTag:22];
UILabel *date = (UILabel *)[cell viewWithTag:23];
UILabel *time = (UILabel *)[cell viewWithTag:24];
valuedate.text=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:#"offerTitle"];
msg.text=#"How are you?";
NSString *img=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:#"offerPhoto"];// here i am getting image path
UIImage *img1 = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:img]]];
cell.imageView.image=img1;// here i am setting image due to which app is so heavy and stuck
return cell;
}

Answer 1

Dont use imageWithData: for setting images. It is synchronous and will make your app run slow.
Instead of that Use SDWebImage
You just need to do following things:
Dump SDWebImage folder into your project.
Import UIImageView+WebCache.h.
Set the image using: sd_setImageWithURL:
OR
by GCD (Grand Central Dispatch) and sending asynchronous requests. Code copied from HERE.
First implement following method.
- (void)downloadImageWithURL:(NSURL *)url completionBlock:(void (^)(BOOL succeeded, UIImage *image))completionBlock
{
NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
[NSURLConnection sendAsynchronousRequest:request
queue:[NSOperationQueue mainQueue]
completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {
if ( !error )
{
UIImage *image = [[UIImage alloc] initWithData:data];
completionBlock(YES,image);
} else{
completionBlock(NO,nil);
}
}];
}
and then in your cellForRowAtIndexPath
[self downloadImageWithURL:your_url completionBlock:^(BOOL succeeded, UIImage *image) {
if (succeeded) {
// change the image in the cell
cell.imageView.image = image;
}
}];

Answer 2

try this below code, hope this helps u .
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
__block tablecellTableViewCell *cell= [self.activitiesTableView_ dequeueReusableCellWithIdentifier:tableviewidentifier];
if(cell==nil)
{
cell = [[tablecellTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:tableviewidentifier];
}
if(indexPath.row == [self tableView:tableView numberOfRowsInSection:indexPath.section] - 1)
{
// [[cell textLabel] setText:#"Load more records"];
}
UILabel *valuedate = (UILabel *)[cell viewWithTag:21];
UILabel *msg = (UILabel *)[cell viewWithTag:22];
UILabel *date = (UILabel *)[cell viewWithTag:23];
UILabel *time = (UILabel *)[cell viewWithTag:24];
valuedate.text=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:#"offerTitle"];
msg.text=#"How are you?";
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
NSString *img=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:#"offerPhoto"];// here i am getting image path
NSURL *url = [NSURL URLWithString:img];
NSData * imageData = [NSData dataWithContentsOfURL:url];
UIImage *image = [UIImage imageWithData:imageData];
dispatch_sync(dispatch_get_main_queue(), ^{ //in main thread update the image
cell.imageView.image = image;
cell.textLabel.text = #""; //add this update will reflect the changes
});
});
return cell;
}
EDIT
in order to reuse the downloaded image u can either save them on disk or just for save them some where for example in dictionary for temporary using
in below code i took one example dictionary, and strong the download images with row as key
#interface ViewController ()
{
NSMutableDictionary *imagesDictionary; //lets declare a mutable dictionary to hold images
}
in this method just initialise it
- (void)viewDidLoad {
[super viewDidLoad];
// rest of your code
//...........
//
imagesDictionary = [[NSMutableDictionary alloc]init]; //initilise
}
in index this method just add the downloaded images to dictionary for corresponding row as key
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
__block tablecellTableViewCell *cell= [self.activitiesTableView_ dequeueReusableCellWithIdentifier:tableviewidentifier];
if(cell==nil)
{
cell = [[tablecellTableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:tableviewidentifier];
}
if(indexPath.row == [self tableView:tableView numberOfRowsInSection:indexPath.section] - 1)
{
// [[cell textLabel] setText:#"Load more records"];
}
__block NSString *row = [NSString stringWithFormat:#"%d",indexPath.row]; //add this
UILabel *valuedate = (UILabel *)[cell viewWithTag:21];
UILabel *msg = (UILabel *)[cell viewWithTag:22];
UILabel *date = (UILabel *)[cell viewWithTag:23];
UILabel *time = (UILabel *)[cell viewWithTag:24];
// valuedate.text=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:#"offerTitle"];
msg.text=#"How are you?";
if(![[imagesDictionary allKeys] containsObject:row]) //if image not found download and add it to dictionary
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
// NSString *img=[[self.inboxmessagesarray objectAtIndex:indexPath.row]objectForKey:#"offerPhoto"];// here i am getting image path
NSURL *url = [NSURL URLWithString:img];
NSData * imageData = [NSData dataWithContentsOfURL:url];
UIImage *image = [UIImage imageWithData:imageData];
dispatch_sync(dispatch_get_main_queue(), ^{ //in main thread update the image
[imagesDictionary setObject:image forKey:row]; //sorry, while editing to your code i forgot to add this
cell.imageView.image = image;
cell.textLabel.text = #""; //add this update will reflect the changes
NSLog(#"loading and addig to dictionary");
});
});
}
else
{
cell.imageView.image = [imagesDictionary objectForKey:row];
NSLog(#"retriving from dictioary");
}
return cell;
}

Answer 3

First of all you are calling dataWithContentsOfURL: function which will make the app non responsive because you are calling it on main thread. To make it responsive you need to create a custom cell YourCell and declare a method in YourCell.h
#interface YourCell : UITableViewCell
{
UIImage *_cImage;
}
- (void)downloadImageFromURL:(NSURL *)imageUrl;
#end
Now in YourCell.m you need to do like this:
- (void)downloadImageFromURL:(NSURL *)imageUrl
{
if (_cImage != nil)
{
self.imageView.image = _cImage;
}
else
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
_cImage = [UIImage imageWithData:[NSData dataWithContentsOfURL:imageUrl]];
dispatch_sync(dispatch_get_main_queue(), ^{
self.imageView.image = _cImage;
});
});
}
}
Now from cellForRowAtIndexPath: you just need to call downloadImageFromURL: function of YourCell and pass the imageUrl to it and its the cell responsibility to download and show the image.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier= #"YourCell";
YourCell *cell = (YourCell *)[self.activitiesTableView_ dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[[NSBundle mainBundle] loadNibNamed:#"YourCell" owner:self options:nil] objectAtIndex:0];
}
// Set your UILabels as before.....
NSString *imagePath=[[self.inboxmessagesarray objectAtIndex:indexPath.row] objectForKey:#"offerPhoto"];
[cell downloadImageFromURL:[NSURL URLWithString:imagePath]];
return cell;
}
Let me know if you have any questions.

Answer 4

UIImageView *img1 = (UIImageView *)[cell viewWithTag:104];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
dispatch_async(dispatch_get_main_queue(), ^{
img1.image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:img]]];
});
});
Send async requests for images. Doing this would not block your UI until the image gets loaded.