CODEWITHSUNDEEP
iosobjective-cuitableview
syedfa
syedfa

Reputation: 2809

Not saving data for some reason after call to insertRowToIndexPath in iOS

I have a UITableView in my app where I have the user add rows to the table. I do this by calling "insertRowAtIndexPath":

- (IBAction)addRow:(id)sender {

    NSString *theObjectToInsert = [NSString stringWithFormat:@"Row #: %lu", (unsigned long)[self.tableData count]];
    [self.tableData addObject:theObjectToInsert];
    NSLog(@"What is the count of the collection? %lu", self.tableData.count-1);
    NSIndexPath *newPath=[NSIndexPath indexPathForRow:self.tableData.count-1 inSection:0];
    [self.myTable insertRowsAtIndexPaths:@[newPath] withRowAnimation:UITableViewRowAnimationAutomatic];
    [self.myTable scrollToRowAtIndexPath:newPath atScrollPosition:UITableViewScrollPositionBottom animated:YES];


}

My problem that I've discovered is that after adding the necessary rows, I am not saving the data as I think I should. Here is the method that is supposed to store the data:

- (void)saveAction {

    //I iterate through my entire UITableView to tally up the data from all of the rows
    NSMutableArray *cells = [[NSMutableArray alloc] init];
    for (NSInteger j = 0; j < [self.myTable numberOfSections]; ++j) {
        for (NSInteger i = 0; i < [self.myTable numberOfRowsInSection:j]; ++i) {
            if ([self.myTable cellForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:j]]) {
                [cells addObject:[self.myTable cellForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:j]]];
            }
        }
    }

    NSLog(@"The number of table rows are: %lu", (unsigned long)[cells count]);  

}

For some reason, this only prints out "4", even though I've added much more. Can anyone see what it is I'm doing wrong?

Upvotes: 0

Views: 71

Answers (3)

Abhinav
Abhinav

Reputation: 38162

This is not the right way to find out how many rows have been created by far. I believe you must be using dequeueing feature of table views in your cellForRowAtIndexPath: method. This features allows only visible cells in memory and not all. So, even if you have 50 data sets in your model you will feel 50 cells existing but NO - at any point in time, you shall get only visible cells count. Key here is - Cells which are not visible on screen are discarded by iOS.

Your model count (self.tableData.count) is the right way to know how many cells you may have.

Upvotes: 1

Ramaraj T
Ramaraj T

Reputation: 5230

Why would u save the UITableViewCell in the cells array? while u already have all the datas in the self.tableData array. Never store/access the UI object, just use the datamodel.

And coming to the point, from UITableView docs, the cellForRowAtIndexPath returns nil if the cell is not visible. So even though you have 10 cells, if only 4 cells are visible, then this method will return nil for the remaining 6 cells.

- (nullable __kindof UITableViewCell *)cellForRowAtIndexPath:(NSIndexPath *)indexPath;   
// returns nil if cell is not visible or index path is out of range

Upvotes: 2

Tj3n
Tj3n

Reputation: 9933

Why don't you do the reverse, make a copy of your dataArray as table datasource, on the addRow then add it into the datasource array, reload table, when hit save then make the dataArray = dataArrayCopy, it will be much easier if you modify the datasource than the table itself

Upvotes: 1

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