Question

I’m writing a small project time management program for myself and have run into a problem which has confounded me.

They way it’s set up is that I have an object called TCObject which I use in another object called ProjectTimerController. ProjectTimerController is a NSWindowController and it has it’s own NIB file.

What I’m doing is pretty straight forward. When you click a line in a NSTableView ProjectTimerController finds a TCObject which corresponds to that line. It then loads info from that TCObject into an interface where you can view and edit some stuff.
Here’s a screenshot of what it looks like:

Now when I change the text in NSTextView and then press the Add button the -saveString function is called and currentSelection (which is a TCObject and represents the currently selected line) and it’s notes variable is set. I know that _notes is set as the new value as NSLog function logs the correct string being in _notes when setString is run. The same, correct, string is logged in -tableViewSelectionDidChange: just before currentSelection is set as the newly selected object.

But if I select the line where I just changed the notes it just loads the same text, “Initial String” and checking _notes tells me it’s “Initial String”.

Thing I don’t have this problem with isFinished. When the Finished check box is toggled I set the corresponding TCObjects‘ isFinished Boolean value to the same value as the checkbox. This the object remembers and correctly changes depending on what line I have selected.

[EDIT]
*I’ve added a clearer explanation here.

1. I click a line in the NSTableView (lets say the top one)

2. This loads a corresponding TCObject from the myProjects array and that object’s variable are added to the Notes NSTextView box and Finished is toggled on or off.

3. If I now write into The Notes box and press “Add” the text there is set into that TCObject’s _notes variable.

4. So If I click another line some other text is loaded into the Notes box. Clicking back on the top line should give me the string I just wrote into Notes in step 3. But it doesn’t. _notes always seems to contain the string I set when I initialize it in the -init method.

5. The “Finished” checkbox works fine. When I click that the state is saved and loaded correctly when I click a line.

6. I know that _notes is correctly set when I press the Add button as the NSLog method in setString logs the string I have written into Notes when I press the Add button.

[/EDIT]

Here below is a barebones version of TCObject and ProjectTimerController.

//TCObject.h
@interface TCObject : NSObject
{
    NSString *_notes;
    Boolean _isFinished;
}

@property (retain, nonatomic) NSString *notes;
@property (nonatomic) Boolean isFinished;

@end

//TCObject.m
#import "TCObject.h"

@implementation TCObject
@synthesize notes = _notes, isFinished = _isFinished;

-(id)init{
    if (self = [super init]) {
        self.notes = @"Initial string";
        self.isFinished = NO;
    }
    return self;
}

- (void)dealloc {   
    [_notes release]; _notes = nil;
    [super dealloc];
}


-(void)setNotes:(NSString *)notes {
    [notes retain];
    [_notes release];
    _notes = notes;
    NSLog(@"Setting _notes as: %@", _notes);

}


-(NSString *)notes {

    NSLog(@"Getting _notes, which is: %@", _notes);
    return _notes;
}

@end

//ProjectTimerController.m
- (id)initWithWindow:(NSWindow *)window {
    self = [super initWithWindow:window];
    if (self)
    {
        myProjects = [[NSMutableArray alloc]init];
        currentSelection = nil;

        TCObject *newProject = [[TCObject alloc] init];
        TCObject *newProject2 = [[TCObject alloc] init];
        TCObject *newProject3 = [[TCObject alloc] init];
        TCObject *newProject4 = [[TCObject alloc] init];

        [myProjects addObject:newProject];
        [myProjects addObject:newProject2];
        [myProjects addObject:newProject3];
        [myProjects addObject:newProject4];
    }
    return self;
}


-(IBAction)isFinishedToggle:(id)sender {
    if(currentSelection != nil){
        currentSelection.isFinished = finishedCheckBtn.state;
    }
}


-(IBAction)saveString:(id)sender {
    if(currentSelection != nil){
        currentSelection.notes = [[notesField textStorage] string];
    }
}

//delegate function for NSTableView
- (void)tableViewSelectionDidChange:(NSNotification *)aNotification {
    NSInteger selectedIndex = [table selectedRow];

    if(selectedIndex == -1){
        return;
    }
    //here the correct notes string is printed
    NSLog(@"curr: %i", currentSelection.notes);

    currentSelection = [myProjects objectAtIndex:selectedIndex];

    NSString *notesInfo = currentSelection.notes;
    Boolean isFinishedInfo = currentSelection.isFinished;

    [notesField setString:notesInfo];
    [finishedCheckBtn setState:isFinishedInfo];
}

Answer 1

Finally found the problem. Seems that changing notes in this way:

-(IBAction)saveString:(id)sender {
    if(currentSelection != nil){
        currentSelection.notes = [[notesField textStorage] string];
    }
}

causes some problems. Everything works fine if I do it this way:

-(IBAction)saveString:(id)sender{
    if(currentSelection != nil){
        NSString *temps = [NSString stringWithFormat:@"%@", [[notesField textStorage] string]];
        currentSelection.notes = temps;
    }
}

So I’m guessing what was going on is that _notes was pointing to the text contained in my NSTextView. So when I changed the text there _notes also changed or something like that…