iOS - Reload element from table view cell - ios

Question

I'd like to implement a "like" functionality in a table view. Each row has a like button and a like counter.
When the user taps "like" the like counter should be increased by one. If the same user taps again, the like counter is decreased by one.
I have implemented this using reloadRowsAtIndexPaths. However, this reloads the whole cell and it is bad in terms of usability.
Would you know a simple mechanism to implement such a functionality? The main requirement is that only the like counter is updated, not the whole cell or table.
Thanks in advance,
Tiago

Answer 1

U don't need to reload a whole cell, simply change the title/image for your like button.
Smth. like this:
#pragma mark - custom table cell
#interface TableCellWithLikeButton : UITableViewCell
#property (weak, nonatomic) IBOutlet UIButton *userLikeButton;
#end
#implementation TableCellWithLikeButton
#end
#pragma mark - User modal
#interface User:NSObject
#property (assign, nonatomic) BOOL wasLiked;
#property (assign, nonatomic) NSInteger likesCounter;
#end
#implementation User
#end
#implementation VC1
{
IBOutlet UITableView *_tableView;
NSMutableArray *_users;
}
- (id)initWithCoder:(NSCoder*)aDecoder
{
if(self = [super initWithCoder:aDecoder]) {
_users = [NSMutableArray array];
for (int i=0;i<100;i++) {
User *user = [User new];
[_users addObject:user];
}
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
}
#pragma mark - UITableViewDataSource
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return _users.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = #"CellWithLikeButton";
TableCellWithLikeButton *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
[cell.userLikeButton addTarget:self action:#selector(changeLikeStatus:) forControlEvents:UIControlEventTouchUpInside];
User *user = _users[indexPath.row];
[cell.userLikeButton setTitle:user.wasLiked?#"Liked":#"Like" forState:UIControlStateNormal];
cell.userLikeButton.tag = indexPath.row;
return cell;
}
- (void)changeLikeStatus:(UIButton *)likeButton
{
User *user = _users[likeButton.tag];
user.likesCounter += user.wasLiked?-1:1;
user.wasLiked = !user.wasLiked;
[likeButton setTitle:user.wasLiked?#"Liked":#"Like" forState:UIControlStateNormal];
}
#end