How to save button selection on UITableViewCell? - ios

Question

My app has a favourite button, on clicking it is converting into red heart and if I click againg then it is back to gray heart. Its working correct. But problem is reuseIdentifier,After scrolling, button just coming to original state because its resusing cell here.
How can I save selection of button so that they remain selected(if selected)
Code of tableViewCell class(.h file):
#import <UIKit/UIKit.h>
#interface favBTNTableViewCell : UITableViewCell
#property(nonatomic)UIButton *faVbtn;
#end
Code of tableViewCell class(.m file)
#import "favBTNTableViewCell.h"
#implementation favBTNTableViewCell
#synthesize faVbtn;
-(id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(nullable NSString *)reuseIdentifier
{
self=[super initWithStyle:style reuseIdentifier:reuseIdentifier];
if(self)
{
faVbtn=[UIButton new];
[faVbtn setFrame:CGRectMake(10, 10, 25, 25)];
[faVbtn setBackgroundImage:[UIImage imageNamed:#"unsel"] forState:UIControlStateNormal];
[faVbtn addTarget:self action:#selector(clickOnfav) forControlEvents:UIControlEventTouchUpInside];
[faVbtn setSelected:YES];
[self.contentView addSubview:faVbtn];
}
return self;
}
-(void)clickOnfav
{
if ([faVbtn isSelected]) {
[faVbtn setBackgroundImage:[UIImage imageNamed:#"sel.jpg"] forState:UIControlStateNormal];
[faVbtn setSelected:NO];
}
else
{
[faVbtn setSelected:YES];
[faVbtn setBackgroundImage:[UIImage imageNamed:#"unsel"] forState:UIControlStateNormal];
}
}
Code of ViewContrller.m
#import "ViewController.h"
#import "favBTNTableViewCell.h"
#interface ViewController ()<UITableViewDataSource,UITableViewDelegate>
{
NSString *ci;
}
#property (strong, nonatomic) IBOutlet UITableView *tv;
#end
#implementation ViewController
-(NSInteger)tableView:(nonnull UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 30;
}
-(UITableViewCell*)tableView:(nonnull UITableView *)tableView cellForRowAtIndexPath:(nonnull NSIndexPath *)indexPath
{
favBTNTableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:ci];
if(!cell)
{
cell=[[favBTNTableViewCell alloc]init];
cell.faVbtn.tag=indexPath.row;
}
return cell;
}
- (void)viewDidLoad {
_tv.delegate=self;
_tv.dataSource=self;
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}

Answer 1

You need corresponding data source for your cells. For this purpose you can, for example, create one more class and you will use it like an item for data source. Take a look:
#interface DataSourceItem : NSObject
#property (nonatomic, assign) BOOL isFavorite;
#end
#implementation DataSourceItem
#end
Then in view controller's code you need to populate array of data source items and manage your table view depending on this array:
#interface ViewController ()<UITableViewDataSource,UITableViewDelegate>
{
NSString *ci;
}
#property (strong, nonatomic) IBOutlet UITableView *tv;
#property (strong, nonatomic) NSArray *dataSourceArray;
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
_tv.delegate=self;
_tv.dataSource=self;
NSMutableArray *temp = [NSMutableArray new];
// actually how many rows you table view need to have
for (NSUInteger i = 0; i < 30; i++)
{
[temp addObject:[DataSourceItem new]];
}
self.dataSourceArray = [temp copy];**
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// change dataSource item state
DataSourceItem *item = [self.dataSourceArray objectAtIndex:indexPath.row];
item.isFavorite = !item.isFavorite;
// change cell state
favBTNTableViewCell *cell = [self tableView:tableView cellForRowAtIndexPath:indexPath];
cell.faVbtn.selected = item.isFavorite;
}
-(NSInteger)tableView:(nonnull UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [self.dataSource count];
}
-(UITableViewCell*)tableView:(nonnull UITableView *)tableView cellForRowAtIndexPath:(nonnull NSIndexPath *)indexPath
{
favBTNTableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:ci];
if(!cell)
{
cell=[[favBTNTableViewCell alloc]init];
cell.faVbtn.tag=indexPath.row;
}
// decision based on data source item state
cell.favBtn.selected = self.dataSource[indexPath.row];
return cell;
}

Answer 2

You can fix it like this:
Implement - (void)layoutSubviews method in your custom cell.
In - (void)layoutSubviews, check button state and then set the
right image on it:
->
- (void)layoutSubviews {
[super layoutSubviews];
UIImage *buttonImage = [faVbtn isSelected] ? [UIImage imageNamed:#"sel.jpg"] : [UIImage imageNamed:#"unsel"];
[faVbtn setBackgroundImage:buttonImage forState:UIControlStateNormal];
}

Answer 3

if you are using custom cell
register class/nib for your tableview in did load
[tblName registerNib:[UINib nibWithNibName:#"customCell" bundle:nil] forCellReuseIdentifier:#"customCell"];
henceforth in datasource method
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
customCell *cell =(customCell*) [tableView dequeueReusableCellWithIdentifier:#"customCell" forIndexPath:indexPath];
// your code here
return cell;
}
Do not forget to assign your cell identifier as "customCell" in cell attribute
Happy coding..
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