Multi-select cell in UITableView in sequence - ios

Question

I have a UITableView with numerous cells. I'm able to multi select cells but what I want is that user only can select multiple cells in sequence. ie if user has selected 2nd row then he/she only can select 3rd cell then 4th in sequence, doesn't allow to select random cells.
Here is what I've done:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return arrPackages.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
PurchaseListTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"PurchaseListTableViewCell" forIndexPath:indexPath];
NSDictionary *dict = [arrPackages objectAtIndex:indexPath.row];
cell.lblPackageName.text = [dict valueForKey:#"package_name"];
cell.lblDiscount.text = [NSString stringWithFormat:#"You save: %#%%",[dict valueForKey:#"discount"]];
cell.lblLastAmount.text = [NSString stringWithFormat:#"%#",[dict valueForKey:#"package_price"]];
NSString *strPaymentStatus = [NSString stringWithFormat:#"%#",[dict valueForKey:#"payment_status"]];
if ([strPaymentStatus isEqualToString:#"2"]) {
cell.contentView.userInteractionEnabled = NO;
}
else{
cell.contentView.userInteractionEnabled = YES;
}
/*
NSMutableAttributedString *attributeString = [[NSMutableAttributedString alloc] initWithString:#"Your String here"];
[attributeString addAttribute:NSStrikethroughStyleAttributeName
value:#2
range:NSMakeRange(0, [attributeString length])];
*/
return cell;
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return 100;
}
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// NSDictionary *dict = [_arrModuleData objectAtIndex:indexPath.row];
}
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
return YES;
}
- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath {
return UITableViewCellEditingStyleDelete | UITableViewCellEditingStyleInsert;
}

Answer 1

You can implement the tableview delegate method tableView(_:willSelectRowAt:) and return nil if you don't want to select the current index path, else you just return the given index path.
Objective-C:
-(NSIndexPath*)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSArray<NSIndexPath *> *selectedIndexPaths = [tableView indexPathsForSelectedRows];
if (selectedIndexPaths == nil || selectedIndexPaths.count == 0) {
return indexPath;
}
NSArray<NSIndexPath *> *sortedIndexPaths = [[selectedIndexPaths sortedArrayUsingComparator:^NSComparisonResult(NSIndexPath * _Nonnull index1, NSIndexPath * _Nonnull index2) {
return index1.row < index2.row;
}] filteredArrayUsingPredicate:[NSPredicate predicateWithFormat: #"section = %d", indexPath.section]];
if (indexPath.row >= sortedIndexPaths[0].row &&
indexPath.row <= sortedIndexPaths[sortedIndexPaths.count-1].row) {
return indexPath;
}
return nil;
}
Swift:
func tableView(_ tableView: UITableView, willSelectRowAt indexPath: IndexPath) -> IndexPath? {
guard let selectedIndexPaths = tableView.indexPathsForSelectedRows,
selectedIndexPaths.count > 0 else {
return indexPath
}
let indexes = selectedIndexPaths
.filter { $0.section == indexPath.section }
.sorted()
if let first = indexes.first,
let last = indexes.last,
indexPath.row >= first.row - 1 && indexPath.row <= last.row + 1 {
return indexPath
}
return nil
}
Of course you should code a similar behavior for tableView(_:willDeselectRowAt:)