Table View Indexing or Sorting Image Array, Description Array According to Name Array

Introduction

In this article, we will explore how to achieve indexing or sorting of image array, description array according to name array in a table view. We will cover the common pitfalls and solutions for this issue.

Understanding the Problem

The problem arises when we are trying to display multiple arrays (description array and image array) along with the name array in a table view. The issue is that the images and descriptions are repeating themselves for new sections, whereas we want them to be sorted according to the name array.

For example, let’s say we have three arrays: nameArray, imageArray, and descriptionArray. We want to display these arrays in a table view with indexing or sorting based on the nameArray.

Reusing UITableViewCell

The issue is often caused by reusing UITableViewCell for each row in the table view. This means that the old values of the labels and images are not being cleared, resulting in the repetition of data.

To fix this issue, we need to clear the values of the labels and images as the first line of the cellForRowAtIndexPath function.

Clearing Label Values

Let’s take a closer look at how we can clear the label values:

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefaultreuseIdentifier:CellIdentifier];
    }

    // Clear the label values
    cell.textLabel.text = nil;
    cell.detailTextLabel.text = nil;

    // ... rest of the code ...
}

Creating Custom Table View Cell Class

We can create a custom UITableViewCell class to make it easier to manage the labels and images.

// MyCustomTableViewCell.h

#import <UIKit/UIKit.h>

@interface MyCustomTableViewCell : UITableViewCell

@property (nonatomic, strong) UILabel *nameLabel;
@property (nonatomic, strong) UIImageView *imageLabel;

@end

Creating Custom Table View Cell Class (continued)

We can then create an instance of this custom cell class and set its labels and images:

// MyCustomTableViewCell.m

#import "MyCustomTableViewCell.h"

@implementation MyCustomTableViewCell

- (instancetype)initWithStyle:(UITableViewCellStyle)style
    reuseIdentifier:(NSString *)reuseIdentifier
      onTap:(void (^)(void))onTap {
    self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
    if (self) {
        // Initialize the labels and images
        self.nameLabel = [[UILabel alloc] init];
        self.imageLabel = [[UIImageView alloc] init];

        // Set up the labels and images
        self.nameLabel.frame = CGRectMake(95, 2, 225, 25);
        self.imageLabel.frame = CGRectMake(95, 27, 225, 15);

        [self.contentView addSubview:self.nameLabel];
        [self.contentView addSubview:self.imageLabel];

        // Set up the tap gesture recognizer
        UITapGestureRecognizer *tapGestureRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(onTap)];
        self.addGestureRecognizer(tapGestureRecognizer);
    }
    return self;
}

- (void)onTap {
    onTap();
}

@end

Table View Data Source and Delegate

We need to update the tableView:cellForRowAtIndexPath: function to use our custom table view cell class.

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

{

    static NSString *CellIdentifier = @"Cell";

    MyCustomTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        cell = [[MyCustomTableViewCell alloc] initWithStyle:UITableViewCellStyleDefaultreuseIdentifier:CellIdentifier];
    }

    // Clear the label values
    cell.nameLabel.text = nil;
    cell.imageLabel.image = nil;

    // Set up the data for the labels and images
    NSArray *listData =[self.tableContents objectForKey:[self.sortedKeys objectAtIndex:indexPath.section]];
    NSString *name = [listData objectAtIndex:indexPath.row];
    NSString *imageURL = [listData objectAtIndex:indexPath.row + 1];

    // ... rest of the code ...

    return cell;
}

Conclusion

In this article, we covered how to achieve indexing or sorting of image array, description array according to name array in a table view. We discussed the common pitfalls and solutions for this issue, including reusing UITableViewCell and creating custom table view cell classes.

By following these steps, you should be able to display your data in a sorted and indexed manner.

Example Use Case

Here is an example use case for the above code:

// MyViewController.h

#import <UIKit/UIKit.h>

@interface MyViewController : UIViewController

@property (nonatomic, strong) UITableView *tableView;

@end

// MyViewController.m

#import "MyViewController.h"

@implementation MyViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    self.tableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 0, 300, 400)];
    self.tableView.dataSource = self;
    self.tableView.delegate = self;

    [self.view addSubview:self.tableView];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    NSArray *listData =[self.tableContents objectForKey:[self.sortedKeys objectAtIndex:section]];
    return listData.count;
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellIdentifier = @"Cell";

    MyCustomTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {
        cell = [[MyCustomTableViewCell alloc] initWithStyle:UITableViewCellStyleDefaultreuseIdentifier:CellIdentifier];
    }

    // Clear the label values
    cell.nameLabel.text = nil;
    cell.imageLabel.image = nil;

    // Set up the data for the labels and images
    NSArray *listData =[self.tableContents objectForKey:[self.sortedKeys objectAtIndex:indexPath.section]];
    NSString *name = [listData objectAtIndex:indexPath.row];
    NSString *imageURL = [listData objectAtIndex:indexPath.row + 1];

    cell.nameLabel.text = name;
    cell.imageLabel.image = [UIImage imageNamed:imageURL];

    return cell;
}

@end

This code creates a table view with custom cells that display the data in a sorted and indexed manner.

Last modified on 2023-06-23