TableView duplicating and overwriting previous data?

ChrisYates · May 2012

Hi,

I'm new to saving data etc so bear with me.

I have a textView and a tableView. I'm just testing something at the moment to ensure I can execute my idea.

It's pretty simple, here's how it works. User types text into textview and when clicking the close button of the textView the text is added to the tableView.

I've got that working but every time I add some more text to the textView and click the close button, the previous stuff gets overwritten in the tableView and a duplicate record shows...can someone advise what I might be doing wrong...thanks.

This is the code I'm using to get the string into the table:

-(IBAction)closeButtonMethod:(id)sender
{
    
    NSString *notes;
    notes = [[textView textStorage] string];
    
    NSMutableDictionary *newItem = [NSMutableDictionary dictionary];
	[newItem setValue:notes forKey:@\"itemNotesKey\"];
    
    [notesArray addObject:newItem];
	[notesTable reloadData];
    
}

BrianSlick · May 2012

Every time you hit the button, you create a new dictionary and add it to your array. What do you want it to do?

ChrisYates · May 2012

That's kind of what I want! But not to overwrite the previous entry with the one just saved.

For example user types this in the textView:
"Test 1"

The button is clicked and "Test 1" pops up in the first table cell...groovy!!

The user then types this in the textView:
"Test 2"

The button is clicked and 'Test 2" appears in the first table cell (over writing Test 1) and also appears in the 2nd table cell....Not so groovy!!

BrianSlick · May 2012

Then the problem isn't here, it's where you put data into the table.

ChrisYates · May 2012

Okay I went over my code again but still cannot find any issues, I thought it would be best to add my code here!

-(NSInteger)numberOfRowsInTableView:(NSTableView *)tableView
{
	return [notesArray count];
}

-(void)tableView:(NSTableView *)tableView setObjectValue:(id)anObject tableColumn:(NSTableColumn *)tableColumn row:(NSInteger)rowIndex
{
	NSDictionary *itemDictionary = [notesArray objectAtIndex:rowIndex];
	if (tableColumn == notesColumn)
		return [itemDictionary setValue:anObject forKey:@\"itemNotesKey\"];
    
    else {
        
    }
    
}

-(id)tableView:(NSTableView *)tableView objectValueForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)rowIndex
{
	NSDictionary *itemDictionary = [notesArray objectAtIndex:rowIndex];
		return [itemDictionary valueForKey:@\"itemNotesKey\"];
	
}

Once the close button is clicked, this code fires:

-(IBAction)closeButtonMethod:(id)sender
{
    
    NSString *notes;
    notes = [[textView textStorage] string];
    
    NSMutableDictionary *newItem = [NSMutableDictionary dictionary];
	[newItem setValue:notes forKey:@\"itemNotesKey\"];
    
        [notesArray addObject:newItem];
	[notesTable reloadData];

BrianSlick · May 2012

-(void)tableView:(NSTableView *)tableView setObjectValue:(id)anObject tableColumn:(NSTableColumn *)tableColumn row:(NSInteger)rowIndex
{
	NSDictionary *itemDictionary = [notesArray objectAtIndex:rowIndex];
	if (tableColumn == notesColumn)
		return [itemDictionary setValue:anObject forKey:@\"itemNotesKey\"];
    
    else {
        
    }
    
}

I suspect this code works, but it doesn't make sense to be returning something in a void method. Although I'm not sure why you care about the column in this method but you don't in the other one.

I'd suggest just commenting out this method altogether until you get the immediate issue sorted out.

I'm not seeing the issue yet.

ChrisYates · May 2012

Okay so I'm making some progress with this albeit incredibly slowly...can't believe this is causing such a headache!!

Basically I changed the NSTextView to an NSTextField and it resolves the duplicate issue! Doesn't help much as I still don't know why it's happening but at least something has changed!

So now the code looks like this when adding to the table:

- (IBAction)saveNotesMethod:(id)sender
{
    //NSString *notes = [[notesTextField textStorage] string];
    
    NSString *notes = [testTextField stringValue];
    
    NSMutableDictionary *newItem = [NSMutableDictionary dictionary];
    [newItem setValue:notes forKey:@\"itemNotesKey\"];
    
    [notesArray addObject:newItem];
    [table reloadData];
}

Bear with the method change title as I created a new project to see if that resolved the issue so am currently working with the new project at present. As you can see I was using:

NSString *notes = [[notesTextField textStorage] string];

to get the TextView value but am now using:

NSString *notes = [testTextField stringValue];

To get the TextField value. Maybe this has something to do with it? Clutching at straws I know!

BrianSlick · May 2012

I think I know what the issue is. I was not familiar with the text storage part.

Go back to what you had before, but make this change:

NSString *notes = [[notesTextField textStorage] string] copy];

I'll bet it works. If so, I'll explain what I think is happening.

ChrisYates · May 2012

BrianSlick;434321 said:
I think I know what the issue is. I was not familiar with the text storage part.

Go back to what you had before, but make this change:
NSString *notes = [[notesTextField textStorage] string] copy];
I'll bet it works. If so, I'll explain what I think is happening.

THANK YOU BRIAN :D

Finally it's working. Now I'm going to hazard a guess at what I think the problem was! Because I wasn't copying the TextField data but rather storing the first piece of data available it constantly had that in memory and so was overwriting all the other data and therefore duplicating?

BrianSlick · May 2012

Right idea, I guess. NSTextStorage is a subclass of NSMutableAttributedString, mutable being the important part. I do not see any indication that any of the methods you were using created a copy of the object. So when you added the string to your dictionary again, it was actually the same instance. Thus, there was only one string object, not two, so changing one caused a change in both places. By making a copy, you break that cycle.

I might have been bitten by this myself, but I'm typically shoving strings into copy properties. I don't think the text storage part is strictly necessary, as I have been pulling stuff out using [textView string], but again it does not appear to copy the value.

Watch out for a leak if you are not using ARC.

ChrisYates · May 2012

Thanks for your help on this Brian...really appreciate it. It's enough to make you want to tear your hair out spending 3 days on it!!

You're absolutely right about the textStorage part, there's no need so I have removed it.

Now onto saving the data using CoreData...could be fun! :rolleyes:

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