Nishanth Nishanth - 9 days ago 6
iOS Question

data from server is not getting displayed in tableview

i have 2 screens ,in 1 st when i click a button it should go to 2 nd screen get data from server and display in table view in 2 nd screen.but with following code i am unable to display data in table view

#import "FirstTableViewController.h"

@interface FirstTableViewController ()<NSXMLParserDelegate>
@property(nonatomic,strong)NSXMLParser*xmlparse;
@property(nonatomic,strong)NSMutableString*tempstr;
@property(nonatomic,strong)NSMutableArray*arr;

@end

@implementation FirstTableViewController

- (void)viewDidLoad {
[super viewDidLoad];

NSMutableURLRequest*req=[[NSMutableURLRequest alloc]init];
NSURL*url=[NSURL URLWithString:@"http://www.thomas-bayer.com/sqlrest/CUSTOMER/"];
[req setURL:url];
[[[NSURLSession sharedSession]dataTaskWithRequest:req completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
// SMXMLDocument *document = [SMXMLDocument documentWithData:data error:&error];

NSString*str=[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
_xmlparse=[[NSXMLParser alloc]initWithData:data];
_xmlparse.delegate=self;
[_xmlparse parse];
}] resume];
[_table reloadData];
}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{
_tempstr=[[NSMutableString alloc]initWithString:string];
}

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

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(nullable NSString *)namespaceURI qualifiedName:(nullable NSString *)qName attributes:(NSDictionary<NSString *, NSString *> *)attributeDict;{
if([elementName isEqualToString:@"CUSTOMER"]){
self.tempstr=[[NSMutableString alloc]init];

}
if([elementName isEqualToString:@"CUSTOMERList"]){
self.arr=[[NSMutableArray alloc]init];

}

}
- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(nullable NSString *)namespaceURI qualifiedName:(nullable NSString *)qName;{

if([elementName isEqualToString:@"CUSTOMER"]){
[_arr addObject:self.tempstr];
self.tempstr=nil;
}
// NSLog(@"arr is %@",self.arr);
}
#pragma mark - Table view data source

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return self.arr.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cel" forIndexPath:indexPath];

cell.textLabel.text=[self.arr objectAtIndex:indexPath.row];
return cell;
}

@end

Answer

do two things

First

- (void)viewDidLoad {
[super viewDidLoad];

arr = [NSMutableArray array]; // initilize the memory of array 

NSMutableURLRequest*req=[[NSMutableURLRequest alloc]init];
NSURL*url=[NSURL URLWithString:@"http://www.thomas-bayer.com/sqlrest/CUSTOMER/"];
[req  setURL:url];
[[[NSURLSession sharedSession]dataTaskWithRequest:req completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
    // SMXMLDocument *document = [SMXMLDocument documentWithData:data error:&error];

    NSString*str=[[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
    _xmlparse=[[NSXMLParser alloc]initWithData:data];
    _xmlparse.delegate=self;
    [_xmlparse parse];
}] resume];

}

Second

 - (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(nullable NSString *)namespaceURI qualifiedName:(nullable NSString *)qName;{

if([elementName isEqualToString:@"CUSTOMER"]){
   [_arr addObject:self.tempstr];
    self.tempstr=@"";
}

 if(arr.count >0)
 {
   dispatch_async(dispatch_get_main_queue(), ^{
             [_table reloadData];
        });

  }

 }