Application crashing after an attempt to delete row from UITableView - ios

Question

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
[self.effectsTableView beginUpdates];
Effect *effectToBeDeleted =self.effectsArray[indexPath.row];
[self deleteEffectWithName:effectToBeDeleted.name];
[self.effectsTableView deleteRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, nil] withRowAnimation:UITableViewRowAnimationTop];
[self.effectsArray removeObjectAtIndex:indexPath.row];
[self.effectsTableView endUpdates];
}
}
The above function should in theory delete the rows as they are slided and the delete button is pressed. However the row does not delete instead is visible even after the
[self.effectsTableView deleteRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, nil] withRowAnimation:UITableViewRowAnimationTop];
is called. And after the user scrolls to the bottom of the UITableView, while loading the last row, the app obviously crashes with "*** -[__NSArrayM objectAtIndex:]: index 9 beyond bounds [0 .. 8]" error since one of the objects has been deleted from the array.
the cellForRowAtIndexPath is as follows:
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (!self.effectsArray)
{
[self loadEffectsInArray];
}
static NSString *cellIdentifier = #"EffectsCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
}
Effect *effectCellEffect = [self.effectsArray objectAtIndex:indexPath.row];
NSString *effectCellText = effectCellEffect.name;
[cell.textLabel setText:effectCellText];
cell.textLabel.font = [UIFont systemFontOfSize:[UIFont labelFontSize]];
return cell;
}
Below is the entire .m file for better context:
#import "EffectsManagementTableViewController.h"
#import "Effect+Manage.h"
#import "VLOGAppDelegate.h"
#import "AddEffectViewController.h"
#import "EffectFilterProperty+Manage.h"
#import "Effect.h"
#interface EffectsManagementTableViewController ()
#property (strong, nonatomic) IBOutlet UITableView *effectsTableView;
#property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;
#property (nonatomic, strong) NSMutableArray *effectsArray;
#property (nonatomic, strong) NSString *currSelectedRowTitle;
#end
#implementation EffectsManagementTableViewController
-(NSString *)currSelectedRowTitle
{
if(!_currSelectedRowTitle)
{
_currSelectedRowTitle = #"";
}
return _currSelectedRowTitle;
}
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
VLOGAppDelegate* appDelegate = [UIApplication sharedApplication].delegate;
self.managedObjectContext = appDelegate.managedObjectContext;
self.effectsTableView.dataSource = self;
self.effectsTableView.delegate = self;
}
-(void)viewWillAppear:(BOOL)animated
{
[self loadEffectsInArray];
[self.effectsTableView reloadData];
[self.effectsTableView setNeedsDisplay];
[self.effectsTableView setNeedsLayout];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return 1;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if (!self.effectsArray)
{
[self loadEffectsInArray];
}
return [self.effectsArray count];
}
//4
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (!self.effectsArray)
{
[self loadEffectsInArray];
}
static NSString *cellIdentifier = #"EffectsCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
}
//6
Effect *effectCellEffect = [self.effectsArray objectAtIndex:indexPath.row];
NSString *effectCellText = effectCellEffect.name;
//7
[cell.textLabel setText:effectCellText];
//[cell.detailTextLabel setText:#"5 stars!"];
cell.textLabel.font = [UIFont systemFontOfSize:[UIFont labelFontSize]];
//cell.backgroundColor = [UIColor blackColor];
//cell.textLabel.textColor = [UIColor whiteColor];
//cell.detailTextLabel.textColor = [UIColor grayColor];
//cell.textLabel.highlightedTextColor = self.effectsTableView.tintColor;
return cell;
}
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
// Return YES if you want the specified item to be editable.
return YES;
}
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
[self.effectsTableView beginUpdates];
Effect *effectToBeDeleted =self.effectsArray[indexPath.row];
[self deleteEffectWithName:effectToBeDeleted.name];
[self.effectsTableView deleteRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, nil] withRowAnimation:UITableViewRowAnimationTop];
[self.effectsArray removeObjectAtIndex:indexPath.row];
//[self loadEffectsInArray];
[self.effectsTableView endUpdates];
//[self.effectsTableView reloadData];
//[self.effectsTableView setNeedsLayout];
//[self.effectsTableView setNeedsDisplay];
}
}
-(void)deleteEffectWithName:(NSString *)effectName
{
NSArray *efpForEffectToBeDeleted = [EffectFilterProperty getEffectFilterPropertiesForEffectName:effectName forImmediateEngagement:NO forManagedObjectContext:self.managedObjectContext];
Effect *effectToBeDeleted = [Effect getEffectWithName:effectName forManagedObjectContext:self.managedObjectContext];
for (int i = 0; i < efpForEffectToBeDeleted.count; i++)
{
EffectFilterProperty *currEFP = efpForEffectToBeDeleted[i];
currEFP.relatedEffect = nil;
currEFP.relatedFilterProperty = nil;
[self.managedObjectContext deleteObject:currEFP];
}
[self.managedObjectContext deleteObject:effectToBeDeleted];
NSError *err = nil;
[self.managedObjectContext save:&err];
if (err != nil) {
//Problem while saving
}
}
-(void)loadEffectsInArray
{
self.effectsArray = [[Effect getAllEffectsForManagedObjectContext:_managedObjectContext] mutableCopy];
}
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
Effect *effectCellEffect = [self.effectsArray objectAtIndex:indexPath.row];
self.currSelectedRowTitle = effectCellEffect.name;
[self performSegueWithIdentifier:#"PushedByTableView" sender:self];
}
/*
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:<##"reuseIdentifier"#> forIndexPath:indexPath];
// Configure the cell...
return cell;
}
*/
/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the specified item to be editable.
return YES;
}
*/
/*
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source
[tableView deleteRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationFade];
} else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
*/
/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath
{
}
*/
/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the item to be re-orderable.
return YES;
}
*/
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
// Make sure your segue name in storyboard is the same as this line
if ([[segue identifier] isEqualToString:#"PushedByTableView"])
{
AddEffectViewController *destinationViewController = segue.destinationViewController;
NSString *selectedRowText = self.currSelectedRowTitle;
destinationViewController.effectToManage = [Effect getEffectWithName:selectedRowText forManagedObjectContext:self.managedObjectContext];
}
}
#end
What am I doing wrong here?

Answer 1

where are you beginning your updates, please add
[self.effectsTableView beginUpdates];
before deleting your row and no need of reloading the table when you are writing the begin updates and end updates.
Please don't remove the object from array before deleting the row.

Answer 2

IT'S WORKING
At end of your commitEditingStyle method add this line this will help you
[TableViewForFirstView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];

Answer 3

try this code to add beginUpdatesmethod before delete called
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
[self.effectsTableView beginUpdates];
Effect *effectToBeDeleted =self.effectsArray[indexPath.row];
[self deleteEffectWithName:effectToBeDeleted.name];
[self.effectsTableView deleteRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath, nil] withRowAnimation:UITableViewRowAnimationTop];
[self.effectsArray removeObjectAtIndex:indexPath.row];
[self loadEffectsInArray];
[self.effectsTableView endUpdates];
}

Answer 4

Try this code:
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
Effect *effectToBeDeleted =[self.effectsArray objectAtIndex:indexPath.row];
[self deleteEffectWithName:effectToBeDeleted.name];
[self.effectsArray removeObjectAtIndex:indexPath.row];
[self loadEffectsInArray];
[self.effectsTableView reloadData];
}

Answer 5

As this message, it's crash for reason out of bound, so try check the array index before assign:
Effect *effectToBeDeleted = self.effectsArray > indexPath.row ? self.effectsArray[indexPath.row] : nil;
And
if(self.effectsArray.count > indexpath.row)
[self.effectsArray removeObjectAtIndex:indexPath.row];
else
NSlog("out of bound");