UITableView and alphabetical order - iphone

Question

In my app I parse an XML file then I would like to show the entry of this file in a UITableView. I found on the web how to make section in alphabetical order (like iPhone contacts), it works fine with my app. When i tap on a row in my tableview I want to display another ViewController, in which I will find some information about the row I tapped, but I'm having some problem: when I tap on a row the variable indexPath.row refers to the section and the information in new view controller aren't right. I will post here some screenshot to show you want I'm trying to explain.
In the following pictures you can see how the app should work:
In the following pictures you can see the error of my app:
You can see that in picture 1 the name is the same and in picture 2 you can see that the name it's wrong. I guess it depend on the variable indexPath.row. I will post here the code to create and populate the tableview:
#import "TableWasteViewController.h"
#import "WasteXmlParser.h"
#import "WasteDetailViewController.h"
#interface TableWasteViewController ()
#property(nonatomic,strong)NSArray *arrayWastes;
#property(nonatomic,strong)NSMutableArray *typeOfWaste;
#property(nonatomic,strong)NSMutableArray *typeOfBin;
#property(nonatomic,strong)NSMutableArray *indexWastes;
#property(nonatomic,strong)NSMutableArray *typeOfWasteBackup;
#end
#implementation TableWasteViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
WasteXmlParser *parser = [[WasteXmlParser alloc]init];
[parser parseWasteXml];
self.arrayWastes = [[NSArray alloc]init];
self.arrayWastes = [parser.arrayWastes mutableCopy];
self.indexWastes = [[NSMutableArray alloc]init];
self.typeOfWaste = [[NSMutableArray alloc]init];
self.typeOfBin = [[NSMutableArray alloc]init];
for (int i = 0; i < [self.arrayWastes count]; i++) {
[self.typeOfWaste addObject:[[self.arrayWastes objectAtIndex:i] objectForKey:#"type"]];
[self.typeOfBin addObject:[[self.arrayWastes objectAtIndex:i]objectForKey:#"place"]];
}
for (int i = 0; i < [self.typeOfWaste count]-1; i++) {
char alphabet = [[self.typeOfWaste objectAtIndex:i] characterAtIndex:0];
NSString *uniChar = [NSString stringWithFormat:#"%c", alphabet];
if (![self.indexWastes containsObject:uniChar]) {
[self.indexWastes addObject:uniChar];
}
}
self.typeOfWasteBackup = [self.typeOfWaste mutableCopy];
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return [self.indexWastes count];
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
return [self.indexWastes objectAtIndex:section];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSString *alphabet = [self.indexWastes objectAtIndex:section];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF beginswith[c] %#",alphabet];
NSArray *wastes = [self.typeOfWaste filteredArrayUsingPredicate:predicate];
return [wastes count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
UIFont *myFont = [UIFont fontWithName:#"Arial" size:14.0];
if (cell == nil) {
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
NSString *alphabet = [self.indexWastes objectAtIndex:[indexPath section]];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF beginswith[c] %#", alphabet];
NSArray *wastes = [self.typeOfWaste filteredArrayUsingPredicate:predicate];
if ([wastes count] > 0) {
NSString *cellValue = [wastes objectAtIndex:indexPath.row];
cell.textLabel.font = myFont;
cell.textLabel.numberOfLines = 2;
cell.textLabel.text = cellValue;
}
return cell;
}
- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {
return self.indexWastes;
}
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
NSIndexPath *indexPath = [self.tableWaste indexPathForSelectedRow];
WasteDetailViewController *vc = segue.destinationViewController;
vc.typeOfWaste = [self.typeOfWaste objectAtIndex:indexPath.row];
vc.typeOfBin = [self.typeOfBin objectAtIndex:indexPath.row];
vc.urlPic = [self.arrayWastes[indexPath.row]objectForKey:#"imgUrl"];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
}
- (IBAction)backToHome:(id)sender {
[self dismissViewControllerAnimated:YES completion:nil];
}
#end
I hope you can help me to fix this issue. Thank you

Answer 1

Rows are indexed by section, i.e. the first item in each section has indexPath.row == 0. So in order to look up values in your flattened vc.typeOfWaste and vc.typeOfBin arrays, you're going to need to do something along the lines of your numberOfRowsInSection method, where you filter the flattened array by the alphabet character and then get the item of the filtered array using indexPath.row.
Overall, this approach seems rather messy, having to filter your data repeatedly. Your data structures don't map well to the problem being solved. I would recommend using the TLIndexPathTools data model TLIndexPathDataModel because it's specifically designed for tables and collection views, can organize your data into sections, and can look up items by index path. Would be happy to walk you through a refactor if you like.

Answer 2

It's because the arrays that you're using to pass the data to the WasteDetailViewController, which are "typeOfWaste, typeOfBin, and urlPic" aren't sorted. The sorted array is called "wastes", but it is only available within the numberOfRowsInSection and the cellForRowAtIndexPath methods. You need to be passing the data in the wastes array forward, so rather than sorting the wastes array all the time, just sort it once after you've loaded it.
Add this property:
#interface TableWasteViewController ()
#property (strong, nonatomic) NSArray *sortedWastes;
#end
Now in viewDidLoad
NSString *alphabet = [self.indexWastes objectAtIndex:section];
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF beginswith[c] %#",alphabet];
self.sortedWastes = [self.typeOfWaste filteredArrayUsingPredicate:predicate];
Finally, in prepareForSegue
vc.typeOfWaste = [self.sortedWastes objectAtIndex:indexPath.row];
Your problems all stem from the fact that you are displaying a sorted array, but the array that you are using to pass the data forward is the unsorted array, so the indexPath is completely useless.
Furthermore, your typeOfBin and urlPic are going to be wrong as well. You need to find some way to link all three of your arrays together, so that when you sort one, you sort them all. The method above only keeps your typeOfWaste array sorted.

Answer 3

I also faced this issue few days ago...u need to make one class set properties whatever you want and then add that object in one array after that u can sort array on one property then whole array will be sorted
#import <Foundation/Foundation.h>
#interface HomeFeed : NSObject
#property (nonatomic, copy) UIImage *ItemImage;
#property (nonatomic, copy) NSString *ItemTitle;
#property (nonatomic, copy) NSString *ItemDate;
#property (nonatomic, copy) NSString *ItemDescription;
#property (nonatomic, copy) NSString *ItemHours;
#property (nonatomic, copy) NSString *ItemID;
#property (nonatomic, copy) NSString *itemDetailUrl;
#property (nonatomic, copy) NSString *itemPerson;
#property (nonatomic, copy) NSString *itemThumbUrl;
#property (nonatomic, assign) int ItemDuration;
#end
#import "HomeFeed.h"
#implementation HomeFeed
#synthesize ItemTitle=_ItemTitle, ItemDate=_ItemDate, ItemImage=_ItemImage,ItemID=_ItemID,ItemDuration=_ItemDuration,ItemDescription,ItemHours=_ItemHours,itemDetailUrl,itemPerson,itemThumbUrl;
#end
NSArray*arr=[responseString JSONValue];
NSLog(#"Json Dictionary speakersss : %#",arr);
NSLog(#"Json arr count speaker : %i",arr.count);
for (int i=0; i<arr.count; i++) {
NSDictionary *dict=[[ NSDictionary alloc]init];
dict=[arr objectAtIndex:i];
HomeFeed *feed = [[HomeFeed alloc] init];
feed.ItemTitle = [NSString stringWithFormat:#"%#%#%#",[dict objectForKey:#"firstName"],#" ",[dict objectForKey:#"lastName"]];
feed.ItemDuration = [[NSString stringWithFormat:#"%#", [dict objectForKey:#"count"]] intValue];
feed.itemDetailUrl=[dict objectForKey:#"detailsUrl"];
[self.itemsDataArray addObject:feed];
[itemTitle addObject:feed.ItemTitle];
}
HomeFeed *feed = [[HomeFeed alloc] init];
NSSortDescriptor *sorter = [[NSSortDescriptor alloc] initWithKey:#"ItemTitle" ascending:YES];
[self.itemsDataArray sortUsingDescriptors:[NSArray arrayWithObject:sorter]];
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"SpeakersCustomCell"];
cell.selectionStyle = NO;
cell.accessoryType = NO;
HomeFeed *feed = [self.itemsDataArray objectAtIndex:indexPath.row];
UIImageView *arrow = (UIImageView *)[cell viewWithTag:3];
arrow.image = [UIImage imageNamed:#"accessory.png"];
UILabel *lblLeft = (UILabel *)[cell viewWithTag:1];
UILabel *lblRight = (UILabel *)[cell viewWithTag:2];
lblLeft.text=feed.ItemTitle;
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
HomeFeed *feed=(HomeFeed*)[self.itemsDataArray objectAtIndex:indexPath.row];
self.onlinDetail.strUrl=feed.itemDetailUrl;
NSString *key = #"OrientationStringValue";
NSDictionary *dictionary = [NSDictionary dictionaryWithObject:feed.itemDetailUrl forKey:key];
[[NSNotificationCenter defaultCenter] postNotificationName:#"NotifSpeaker1" object:nil userInfo:dictionary];
}