How to populate JSON data in UITableView using NSUrlConnection? [duplicate] - ios

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This question already has answers here:
populating a tableview with data using JSON and AFNetworking NSDictionary
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JSON data is not loading in slow internet connection? [closed]
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Closed 8 years ago.
I'm building an article reading app.I'm parsing JSON data using NSData in UITableView.
I'm facing an issue that is data is not load in slow internet speed(2g or 3g)means UI is empty.I want to implement NSUrlConnection
but i'm new in iOS development unable to implement NSUrlConnection in my code.
this is my code:
- (void)viewDidLoad
{
[super viewDidLoad];
BOOL myBool = [self isNetworkAvailable];
if (myBool)
{
#try {
// for table cell seperator line color
self.tableView.separatorColor = [UIColor colorWithRed:190/255.0 green:190/255.0 blue:190/255.0 alpha:1.0];
UIBarButtonItem *backbutton1 = [[UIBarButtonItem alloc] initWithTitle:#"" style:UIBarButtonItemStyleBordered target:nil action:nil];
[[self navigationItem] setBackBarButtonItem:backbutton1];
_Title1 = [[NSMutableArray alloc] init];
_Author1 = [[NSMutableArray alloc] init];
_Images1 = [[NSMutableArray alloc] init];
_Details1 = [[NSMutableArray alloc] init];
_link1 = [[NSMutableArray alloc] init];
_Date1 = [[NSMutableArray alloc] init];
NSData* data = [NSData dataWithContentsOfURL:ysURL];
NSArray *ys_avatars = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
if(ys_avatars){
for (int j=0;j<ys_avatars.count;j++)
{
if( ys_avatars[j][#"title"]==[NSNull null] ){
[_Title1 addObject: #""];
}
else{
[_Title1 addObject:ys_avatars[j][#"title"]];
}
if( ys_avatars[j][#"author"]==[NSNull null] ){
[_Author1 addObject: #""];
}
[_Author1 addObject: ys_avatars[j][#"author"]];
if( ys_avatars[j][#"featured_img"]==[NSNull null] ){
[_Images1 addObject: #""];
}
else{
[_Images1 addObject: ys_avatars[j][#"featured_img"]];
}
if( ys_avatars[j][#"content"]==[NSNull null] ){
[_Details1 addObject: #""];
}else{
[_Details1 addObject:ys_avatars[j][#"content"]];
}
if( ys_avatars[j][#"permalink"]==[NSNull null] ){
[_link1 addObject: #""];
}
else{
[_link1 addObject:ys_avatars[j][#"permalink"]];
}
if( ys_avatars[j][#"date"]==[NSNull null] ){
[_Date1 addObject: #""];
}
else{
NSString *newStr=[ys_avatars[j][#"date"] substringToIndex:[ys_avatars[j][#"date"] length]-3];
[_Date1 addObject:newStr];
}
}
}
else
{
NSLog(#"asd");
}
}
#catch (NSException *exception) {
}
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *Cellidentifier1 = #"ysTableViewCell";
ysTableViewCell *cell1 = [tableView dequeueReusableCellWithIdentifier:Cellidentifier1 forIndexPath:indexPath];
long row = [indexPath row];
cell1.TitleLabel1.text = _Title1[row];
cell1.AuthorLabel1.text = _Author1[row];
NSString *StoryUrl = [_Images1[indexPath.row] stringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding];
if(StoryUrl) {
NSArray *subStringsUrl = [yourStoryUrl componentsSeparatedByString:#"/"];
NSString *stripedName = [subStringsUrl lastObject];
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString* filePath =[documentsDirectory stringByAppendingPathComponent: [NSString stringWithFormat:#"%#",stripedName]];
if(filePath) {
UIImage *image = [UIImage imageWithContentsOfFile:filePath];
if(image) {
ysTableViewCell *updateCell =(id)[tableView cellForRowAtIndexPath:indexPath];
if(updateCell)
updateCell.ThumbImage1.image=image;
cell1.ThumbImage1.image=image;
} else {
dispatch_queue_t taskQ = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_async(taskQ, ^{
NSURL *Imageurl = [NSURL URLWithString:yourStoryUrl];
NSData *data = [NSData dataWithContentsOfURL:Imageurl];
UIImage *images1 = [[UIImage alloc] initWithData:data];
NSData *imageData = UIImagePNGRepresentation(images1);
if (![imageData writeToFile:filePath atomically:NO])
{
NSLog((#"Failed to cache image data to disk"));
}
else
{
NSLog(#"the cachedImagedPath is %#",filePath);
}
dispatch_sync(dispatch_get_main_queue(), ^{
ysTableViewCell *updateCell =(id)[tableView cellForRowAtIndexPath:indexPath];
if(updateCell)
updateCell.ThumbImage1.image=images1;
cell1.ThumbImage1.image=images1;
});
});
}
return cell1;
}
Help is appreciated.
Thanks in advance.

Answer 1

This looks really messy, and i suggest you change your whole design.
A basic and cleaner way (but probably not the best/cleanest way) :
Create class to handle outside-of-view related work (JSON parsing here)
Call that class in viewDidLoad to start parsing
Call a method that refreshes your table view with the newly parsed data when the parsing is done (in the JSON class).
That way, the table view will load your placeholders first and then reload itself when it has the data.
In my opinion, a better way would be to populate it before loading it so there is no wait time.
Can you find what you need yourself, or code it alone? or do you need help? If so, with what?
EDIT : You could/should also use the AFNetworking framework that will make your life 10 times easier with JSON/Internet related code.

Answer 2

I usually create a class that handles the load of my data, whether from a URL or local store. You could use AFNetworking, but there is a ton of extra stuff you might not need. The basics of using NSUrlConnection is really easy.
Try this tutorial, it will help you to understand how Apple's implementation works before you add a third party library that masks it for you.
NSUrlConnection Tutorial