NSMutableArray in UITableView - ios

Question

I am just stuck here, I cannot figure it out what I am doing wrong here. I am pretty new to objective c. In my application I am using a UITableView and NSMutableArray to parse data from RSS feed. I want to refresh the whole table with new data when user click on the segment control in the tableview. I have added the segment control in table header section and it works fine with changing the value when segment index changed.
The problem is now when I click on the segment control it adds the new rows in the tableview instead of refreshing the whole table. Here is the code:
- (void)addEarthquakesToList:(NSArray *)earthquakes
{
//NSInteger startingRow = [self.earthquakeList count];
NSInteger earthquakeCount = [earthquakes count];
NSMutableArray *indexPaths = [[NSMutableArray alloc] initWithCapacity:earthquakeCount];
NSLog(#"%d",earthquakeCount);
for (NSInteger row = 0; row < (earthquakeCount); row++)
{
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:row inSection:0];
[indexPaths addObject:indexPath];
}
[self.earthquakeList addObjectsFromArray:earthquakes];
[self.tableView insertRowsAtIndexPaths:indexPaths
withRowAnimation:UITableViewRowAnimationAutomatic];
}
I have tried many other things like [self.tableView reloadData];
I have also tried the following to remove all objects from the array and remove rows from table but it does not display correct number of rows:
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
NSMutableArray *indexPathsToDelete = [[NSMutableArray alloc] init];
for(unsigned int i = 0; i < [self.earthquakeList count]; i++)
{
[indexPathsToDelete addObject:[NSIndexPath indexPathForRow:i inSection:0]];
}
//[self.tableView beginUpdates];
[self.earthquakeList removeAllObjects];
[self.tableView deleteRowsAtIndexPaths:indexPathsToDelete
withRowAnimation:UITableViewRowAnimationFade];
//[self.tableView endUpdates];
//[self.tableView reloadData];
}
And these are my tableView DataSource methods:
- (NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section
{
// The number of rows is equal to the number of earthquakes in the array.
return [self.earthquakeList count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *kEarthquakeCellID = #"EarthquakeCellID";
citsTableViewCell *cell = (citsTableViewCell *)[tableView dequeueReusableCellWithIdentifier:kEarthquakeCellID];
//Get the specific earthquake for this row.
citsFuelFinder *earthquake = (self.earthquakeList)[indexPath.row];
[cell configureWithEarthquake:earthquake];
return cell;
}
In fact when try to include the following in the segment control:
- (void)segmentedControlHasChangedValue
{
int product;
product = fuelType.selectedSegmentIndex;
switch (product)
{
case 0:
productName=1;
[locationManager startUpdatingLocation];
break;
case 1:
productName=2;
//[self.earthquakeList removeLastObject];
if (![self.earthquakeList count])
{
[self.tableView deleteSections:[NSIndexSet indexSetWithIndex:0]
withRowAnimation:UITableViewRowAnimationRight];
}
else
{
NSMutableArray *indexPathsToDelete = [[NSMutableArray alloc] init];
for(unsigned int i = 0; i < [self.earthquakeList count]; i++)
{
[indexPathsToDelete addObject:[NSIndexPath indexPathForRow:i
inSection:0]];
}
//[self.tableView beginUpdates];
//[self.earthquakeList removeAllObjects];
[self.tableView deleteRowsAtIndexPaths:indexPathsToDelete
withRowAnimation:UITableViewRowAnimationFade];
//[self.tableView endUpdates];
[self.tableView reloadData];
//[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES];
}
[locationManager startUpdatingLocation];
break;
case 2:
productName=4;
[locationManager startUpdatingLocation];
break;
case 3:
productName=5;
[locationManager startUpdatingLocation];
break;
default:
break;
}
}
I get this error:
Terminating app due to uncaught exception
'NSInternalInconsistencyException', reason: 'Invalid update: invalid
number of rows in section 0. The number of rows contained in an
existing section after the update (15) must be equal to the number of
rows contained in that section before the update (15), plus or minus
the number of rows inserted or deleted from that section (0 inserted,
15 deleted) and plus or minus the number of rows moved into or out of
that section (0 moved in, 0 moved out).'
* First throw call stack: (0x2e332e83 0x3868f6c7 0x2e332d55 0x2ecdb0af 0x30c8a34d 0x30cb083f 0x6d2d9 0x30aebda3 0x30aebd3f
0x30aebd13 0x30ad7743 0x30bf7c59 0x30bf7a27 0x30cbca25 0x30aaf1a1
0x30ae69fd 0x30ae63ab 0x30abbd79 0x30aba569 0x2e2fdf1f 0x2e2fd3e7
0x2e2fbbd7 0x2e266471 0x2e266253 0x32fa02eb 0x30b1b845 0x6948d
0x38b88ab7)
Any help much appreciated!

Answer 1

Update the source array of tableview, No need to insert new rows.
[self.earthquakeList addObjectsFromArray:earthquakes];
[self.tableView reloadData];

Answer 2

If you add elements to the data source array, no. of rows in the table view will update automatically. You don't need to insert rows. Just insert elements. Implement your method as:
- (void)addEarthquakesToList:(NSArray *)earthquakes
{
[self.earthquakeList addObjectsFromArray:earthquakes];
[self.tableview reloadData];
}

Answer 3

erm, instead of
[self.tableView insertRowsAtIndexPaths:indexPaths
withRowAnimation:UITableViewRowAnimationAutomatic];
try
[self.tableView reloadRowsAtIndexPaths:indexPaths
withRowAnimation:UITableViewRowAnimationAutomatic];
anyways.... your code snippets are still insufficient, for me atleast, to locate your problem.
But since you said:
I want to refresh the whole table with new data when user click on the segment control in the tableview.
If i had to make a segmented tableView with 4 segments that displays different data for different segments, i'd do this:
NOTE: this is a basic example. it doesn't adhere to your specific code but should give you an idea to drop the logic of playing with indexPaths or that manual adding/removing objects from the array and instead use the tableView reloadData appropriately.
- (void)viewDidLoad
{
[super viewDidLoad];
//declare NSArray *arrFirst, *arrSecond, *arrThird, *arrFourth, *arrSelected
//in the .h file
arrFirst = [[NSArray alloc] initWithObjects:#"eins",#"zwei",#"drei",#"vier",#"fünf",#"sechs", nil];
arrSecond = [[NSArray alloc] initWithObjects:#"one",#"two",#"three",#"four",#"five",#"six",#"seven",#"eigth",#"nine", nil];
arrThird = [[NSArray alloc] initWithObjects:#"uno",#"dos",#"tres",#"cuatro",#"cinco", nil];
arrFourth = [[NSArray alloc] initWithObjects:#"ek",#"do",#"teen",#"chaar",#"paach",#"che",#"saat", nil];
arrSelected = arrFirst;
}
- (IBAction)mySegmentsAct:(UISegmentedControl *)sender
{
switch (sender.selectedSegmentIndex)
{
case 0:
arrSelected = arrFirst;
break;
case 1:
arrSelected = arrSecond;
break;
case 2:
arrSelected = arrThird;
break;
case 3:
arrSelected = arrFourth;
break;
default:
arrSelected = nil;
break;
}
[myTableView reloadData];
}
-(NSInteger)tableView:(UITableView *)tableView
numberOfRowsInSection:(NSInteger)section
{
return [arrSelected count];
}
-(UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell == nil)
{
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault
reuseIdentifier:CellIdentifier];
}
cell.textLabel.text = (arrSelected)[indexPath.row];
return cell;
}
I could also do this using a single array as well, by flushing the old array contents first:
arrSelected = nil
and then put the new elements in this array (from some source using some logic)
and finally:
myTableView reloadData.

Answer 4

It looks like when you selected the second segment and the crash came out?
So the following codes cause the error.
[self.tableView deleteRowsAtIndexPaths:indexPathsToDelete
withRowAnimation:UITableViewRowAnimationFade];
When you use deleteRowsAtIndexPaths or insertRowAtIndexPaths, you must insure the length of the datasource matches the current row of tableView.
For example: your tableView already has 10 rows, now you need to delete 2 rows, you should remove 2 data objects from your datasource array first, then call deleteRowsAtIndexPaths.

Answer 5

Try these replacements, and give us some feedback later (specially if any NSAssert "crashed" your app):
- (void)addEarthquakesToList:(NSArray *)earthquakes
{
// data checking
NSAssert(self.earthQuakeList != nil, #"earthQuakeList cannot be nil!");
NSAssert(self.tableView != nil, #"tableView cannot be nil!");
NSAssert(earthquakes != nil, #"earthquakes cannot be nil!");
// relevant implementation
[self.earthquakeList addObjectsFromArray:earthquakes];
[self.tableView reloadData];
}
- (void)segmentedControlHasChangedValue
{
// data checking
NSAssert(self.earthQuakeList != nil, #"earthQuakeList cannot be nil!");
NSAssert(self.tableView != nil, #"tableView cannot be nil!");
NSAssert(fuelType != nil, #"fuelType cannot be nil!");
NSAssert(locationManager != nil, #"locationManager cannot be nil!");
// relevant implementation
switch (fuelType.selectedSegmentIndex)
{
case 0:
productName=1; // what is this?
[locationManager startUpdatingLocation];
break;
case 1:
productName=2;
[self.earthquakeList removeAllObjects];
[locationManager startUpdatingLocation];
break;
case 2:
productName=4;
[locationManager startUpdatingLocation];
break;
case 3:
productName=5;
[locationManager startUpdatingLocation];
break;
default:
break;
}
[self.tableView reloadData]; // if you want to change the data whenever the user changes the UISegmentedControl to any new value, leave this here.
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
// data checking
NSAssert(self.earthQuakeList != nil, #"earthQuakeList cannot be nil!");
NSAssert(self.tableView != nil, #"tableView cannot be nil!");
// relevant implementation
[self.earthquakeList removeAllObjects];
[self.tableView reloadData];
}