I want to delete a row in my table view cell. At the moment, the code will look like this:
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath{
// Remove the row from data model
[listOfAllOpenChats removeObjectAtIndex:indexPath.row];
[tableView reloadData];
}
The problem: I will become an error:
No visible #infterface "NSArray" declares the selector
"removeObjectAtIndex:"
Replace your NSArray listOfAllOpenChats with NSMutableArray,you cannot remote object from NSArray
Your listOfAllOpenChats is probably a NSArray type, which has NOT support to remove or add objects. Change your listOfAllOpenChats array type to NSMutableArray and your problem will be gone.
You can't add or remove objects from an NSArray(immutable). You have to use an NSMutableArray.
Related
I received a memory error while working on a project with Table View.
I replicated the storyboard on a new project and received the same error.
Here's the storyboard layout:
01 - The Storyboard
If the "Back" button is pressed while the Delete button is shown then I get a memory error as below:
02 - Running app and Memory error
The code used for deletion is:
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the specified item to be editable.
return YES;
}
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
// Remove the row from data model
[tableData removeObjectAtIndex:indexPath.row];
// Request table view to reload
[tableView reloadData];
}
I'm posting this question in order to learn more about Xcode and Objective-C.
Has anyone experienced something similar?
What process should I follow to debug this error?
Is there a Apple procedure to report this kind of errors?
This appears to be a bug. Using Instruments, I found that a _canEditRowAtIndexPath: message is being sent to a deallocated instance of CDUTableViewController (after it gets popped off the stack by hitting the back button). This message is never sent when the table is in a UITableViewController instead of a UIViewController -- I have no idea why that would be.
You can get around the problem by either using a UITableViewController, or by creating a strong property for the CDUTableViewController in the CDUViewController, and pushing in code rather than using a segue (that way your CDUTableViewController isn't deallocated on the pop).
Remove this line: [tableView reloadData]; - its implied.
And in the future you don't need to post a screenshot of Xcode just give us the error.
Please do the following. Use a modern property for your ivar, remove the declaration in curly braces in the implementation, and refer to that property as self.tableData everywhere in the class. See comments within:
// 1) add a private interface
#interface CDUTableViewController ()
#property(strong, nonatomic) NSMutableArray *tableData;
#end
#implementation CDUTableViewController
// 2) delete the declaration in braces here
- (void)viewDidLoad
{
[super viewDidLoad];
// 3) refer to self.tableData everywhere in this class
self.tableData = [NSMutableArray arrayWithObjects:#"Egg Benedict", // ...
}
The big fix comes at the time of delete. Update your table to match your model after the delete. Do this only for the delete editing style:
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
if (editingStyle == UITableViewCellEditingStyleDelete) {
[self.tableData removeObjectAtIndex:indexPath.row];
[tableView deleteRowsAtIndexPaths:#[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
}
}
I try to manage to delete a row from an UITable which is part on an UIViewController. I use the Edit button in the navigation bar. Hitting it will put the table rows in edit mode. But when a delete button in a row is pressed I get an error ...'Invalid update: invalid number of rows in section 0…. when using the following:
- (void)setEditing:(BOOL)editing animated:(BOOL)animated {
[super setEditing:editing animated:animated];
[self.tableView setEditing:editing animated:YES];
}
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
NSMutableArray *work_array = [NSMutableArray arrayWithArray:self.inputValues];
[work_array removeObjectAtIndex:indexPath.row];
[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
}
}
What do I miss here? The Apple documentation seems to be outdated somehow.
Thanks
The problem is simple. You are not updating your data model properly before deleting the row from the table.
All you do is create some new array and delete a row from that. That's pointless. You need to update the same array used by the other data source methods such as numberOfRowsInSection:.
The issue you are having is that you are not directly updating your table's data source. You first create a completely new array called work_array based on your data source (I'm assuming it's self.inputValues) and then you remove an item from it, and then try to delete a row, but your tableView's data source still contains the item you intended to remove.
All you need to do is ensure that self.inputValues is a mutable array and directly remove the object at the index for that array, like this:
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
[self.inputValues removeObjectAtIndex:indexPath.row];
[self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
}
}
I hope that helps!
I want to delete a row from my tableview. I cannot find a solution that works from the other simialr questions here.
I know I need to use the following code, But I cant seem to figure out how to properly finish this line of code to make it work.
[dailyIncomeArray removeObjectAtIndex:indexPath.row];
But what goes where is says "dailyIncomeArray"?
[what-goes-here removeObjectAtIndex:indexPath.row];
I have a getData method that populates my tableview. Next I want to be able to swipe to the left and hit that red delete button. Thanks in advance for your help!
Heres the rest of the method
// 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
[dailyIncomeArray removeObjectAtIndex:indexPath.row];
[self.tableView reloadData];
//[tableView deleteRowsAtIndexPaths:[NSMutableArray arrayWithObject:results] 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
}
}
Here's the error I'm receiving. I don't understand what this means.
No visible #interface for 'NSArray' declares the selector 'removeObjectAtIndex:'
I am building an iPhone application that is using a table cell. I set up this code to try to delete cells from the table, but it does not seem to work because I am not using a NSMutableArray. When I swipe I get the delete button but the delete button does not do anything. My question is if I am not using NSMutableArray with my table cell ho can this line: [self.dataArray removeObjectAtIndex:indexPath.row]; work?
Code Used
(BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
return YES; }
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
//remove the deleted object from your data source.
//If your data source is an NSMutableArray, do this
[self.dataArray removeObjectAtIndex:indexPath.row];
} }
Here is the link to the apple doc's on table view programming guide. Table view programming guide It has a easy delegate method that uses NSArray and has an example code you can use for deleting and inserting. The code you have shown above is missing the delegate part in order to perform the delete. Take a look at listing 7.3 that maybe what your looking for.
.
Hello,
I have the following code to set the re-ordering of the tableView.
#pragma mark Row reordering
// Determine whether a given row is eligible for reordering or not.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath {
return YES;
}
// Process the row move. This means updating the data model to <span id="IL_AD6" class="IL_AD">correct</span> the item indices.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath
toIndexPath:(NSIndexPath *)toIndexPath {
NSString *item = [arr objectAtIndex:fromIndexPath.row];
[arr removeObject:item];
[arr insertObject:item atIndex:toIndexPath.row];
}
But when I reload the TableView (note not a TableViewController) The order is set back to what it was before I changed anything.
Now when I setup the editing for this view (the delete buttons) I had to add this line:
[self.mainTableView setEditing:YES animated:YES];
before it appeared in my view.
Is there a similar thing I need to set with the re-ordering of the table view for it to save?
The data is fetched from a Core Data database.
In order to persist the order of the objects I'm afraid you will need to add an attribute for that to your data model. Just use an int / [NSNumber] and recompute them in a loop when a table view row is moved.
When you reload the data, are you re-populating that array with the result of a fetch from your Core Data entity? If so, the changes you made to the array (which I assume is the data source for the TV) will be blown away. If you want those changes to stick, you would need to update the model somehow to make sure the re-population of the array results in the array being indexed the way you need.