由于未捕获的异常'NSInvalidArgumentException 4而终止应用程序

Question

I am new to ios. I am making first app in which i am calling data from server and showing in table view cell but it is giving an exception which is mentioned. data is coming correctly but when i populate my table view cell exception is shown. thanx in advance above below is my code

    - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
        static NSString *tableviewidentifier = @"cell";
        UITableViewCell *cell= [tableView dequeueReusableCellWithIdentifier:tableviewidentifier];
        if(cell==nil){
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:tableviewidentifier];
        }
        NSMutableArray *jsonresultarr=[NSMutableArray new];

        NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://magmasysdev.com/ddc/getAllCompanies.php"]];  // this is your request url

        [request setHTTPMethod:@"GET"];

        [request setValue:@"application/json;charset=UTF-8" forHTTPHeaderField:@"content-type"];

        NSError *err;
        NSURLResponse *response;
        NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];

        NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData:responseData options: NSJSONReadingMutableContainers error: &err];     // here parsing the array

        NSArray *firstArry=[[jsonArray objectAtIndex:1]objectForKey:@"company_data"];

        for (int i=0; i<[firstArry count]; i++)
        {
            NSMutableDictionary *getjsonresponse= [firstArry objectAtIndex:i];

            NSString *Company_Id=[getjsonresponse objectForKey:@"Company_Id"];
            NSString *Company_Name=[getjsonresponse objectForKey:@"Company_Name"];
            NSString *Company_Address=[getjsonresponse objectForKey:@"Company_Address"];
            NSString *Company_Email=[getjsonresponse objectForKey:@"Company_Email"];
            NSString *Company_Tel_Num=[getjsonresponse objectForKey:@"Company_Tel_Num"];
            NSString *Company_Website=[getjsonresponse objectForKey:@"Company_Website"];
            NSString *Company_Fax_Num=[getjsonresponse objectForKey:@"Company_Fax_Num"];
            [jsonresultarr addObject:Company_Id];
            [jsonresultarr addObject:Company_Name];
            [jsonresultarr addObject:Company_Address];
            [jsonresultarr addObject:Company_Email];
            [jsonresultarr addObject:Company_Tel_Num];
            [jsonresultarr addObject:Company_Website];
            [jsonresultarr addObject:Company_Fax_Num];
            cell.textLabel.text=[[jsonresultarr objectAtIndex:indexPath.row]objectForKey:@"Company_Id"]; // getting exception in this line..

        }




            return cell;
    }

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    // Return the number of rows in the section.
    NSMutableArray *jsonresultarr=[NSMutableArray new];

    NSMutableURLRequest *request=[NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"http://magmasysdev.com/ddc/getAllCompanies.php"]];  // this is your request url

    [request setHTTPMethod:@"GET"];

    [request setValue:@"application/json;charset=UTF-8" forHTTPHeaderField:@"content-type"];

    NSError *err;
    NSURLResponse *response;
    NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];

    NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData:responseData options: NSJSONReadingMutableContainers error: &err];     // here parsing the array

    NSArray *firstArry=[[jsonArray objectAtIndex:1]objectForKey:@"company_data"];

    for (int i=0; i<[firstArry count]; i++)
    {
        NSMutableDictionary *getjsonresponse= [firstArry objectAtIndex:i];

        NSString *Company_Id=[getjsonresponse objectForKey:@"Company_Id"];
        NSString *Company_Name=[getjsonresponse objectForKey:@"Company_Name"];
        NSString *Company_Address=[getjsonresponse objectForKey:@"Company_Address"];
        NSString *Company_Email=[getjsonresponse objectForKey:@"Company_Email"];
        NSString *Company_Tel_Num=[getjsonresponse objectForKey:@"Company_Tel_Num"];
        NSString *Company_Website=[getjsonresponse objectForKey:@"Company_Website"];
        NSString *Company_Fax_Num=[getjsonresponse objectForKey:@"Company_Fax_Num"];
        [jsonresultarr addObject:Company_Id];
        [jsonresultarr addObject:Company_Name];
        [jsonresultarr addObject:Company_Address];
        [jsonresultarr addObject:Company_Email];
        [jsonresultarr addObject:Company_Tel_Num];
        [jsonresultarr addObject:Company_Website];
        [jsonresultarr addObject:Company_Fax_Num];



}
    return jsonresultarr.count;
}

Answer 1

the approach, which you've followed is not a good way . For every cell, it calls the web services so that it effects the performance .

 cell.textLabel.text=[[jsonresultarr objectAtIndex:indexPath.row]objectForKey:@"Company_Id"];

Here jsonresultarr has hols the object of NSString not an NSDictionary , So change to like the below

cell.textLabel.text=[jsonresultarr objectAtIndex:indexPath.row];