I'm getting a warning in the following method:
- (void)tableView:(NSTableView *)aTableView
setObjectValue:(id)anObject
forTableColumn:(NSTableColumn *)aTableColumn
row:(int)rowIndex
{
NSString *identifier = [aTableColumn identifier];
Person *person = [employees objectAtIndex:rowIndex];
NSUndoManager *undo = [self undoManager];
[[undo prepareWithInvocationTarget:self] tableView:aTableView setObjectValue:[person valueForKey:identifier] forTableColumn:aTableColumn row:rowIndex];
if(![undo isUndoing])
{
[undo setActionName:#"Edit Person"];
}
[person setValue:anObject forKey:identifier];
[tableView reloadData];
}
I'm trying to implement undo so I figure I would call the same method and just pass the old value. The error I'm getting is "warning: multiple methods named '-tableView:setObjectValue:forTableColumn:row:' found". Any idea why?
The method on NSTableViewDataSource is declared as:
- (void)tableView:(NSTableView *)aTableView setObjectValue:(id)anObject forTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex
Your method uses int as the type of the rowIndex variable. Change that to NSInteger and all will be fine.
The underlying issue is that Objective-C does not support co-variance or contra-variance in method argumentation, leading to the warning.
Note also that you are colluding data model with view layer. Undo in this fashion is going to be very very tricky; if you don't also manage the undo stack in the context of every sort of the table and/or addition/removal of rows, undo is going to apply the value to the wrong row.
You would be far better off reworking your app such that you have a proper separation of model view and controller.
Well, here's what got rid of the warning:
[((MyDocument *)[undo prepareWithInvocationTarget:self]) tableView:aTableView setObjectValue:[person valueForKey:identifier] forTableColumn:aTableColumn row:rowIndex];
Casting to the class that I was in cleared up the ambiguity I suppose.
Related
I'm having trouble with Columns in NSTableview. I want to add an item to a specific column in an instance of NSTableView. (Note that data is a pointer to an instance of NSMutableArray, which is a property of AppDelegate, which is the dataSource)
-(IBAction)addTask:(id)sender
{
[self.data addObject:#""];
[self tableView:_tableView setObjectValue:#"Hello World" forTableColumn: self.column row:0];
[self.tableView reloadData];
}
A tutorial I went through showed me how to edit a single-column NSTableView. However, using the same implementation of the NSTableViewDataSource methods causes tableView to populate both columns. The pertinent implementation from the tutorial:
-(void)tableView:(NSTableView *)tableView
setObjectValue:(id)object
forTableColumn:(NSTableColumn *)tableColumn
row:(NSInteger)row
{
[self.data replaceObjectAtIndex:row withObject:object];
}
I reason part of the issue is that the above method doesn't do anything with the tableColumn parameter, but I'm still learning and have no idea how to proceed. (It's especially hard to find help because many modern tutorials involve view-based NSTableViews, and well I know that is best practice, I don't want to run away from this.) I hope my explanation was clear enough, and any help would be much appreciated.
The reason you are seeing the data populated in multiple columns is you are not differentiating what values go in what columns.
You should think of each item in your array as a row in your table view. If you wish to display different values in columns of that row you need a way to store those different values in the data source object. This can be done by using a concrete model object class that has multiple properties defined or by using a NSDictionary with different keys with their corresponding values.
For adding a row:
-(IBAction)addTask:(id)sender
{
NSMutableDictionary *newRow = [NSMutableDictionary dictionary];
[newRow setObject:#"Hello World" forKey:#"salutation"];
[self.data addObject:newRow];
[self.tableView reloadData];
}
So for the display code:
- (id)tableView:(NSTableView *)aTableView objectValueForTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex
{
NSDictionary *row = [self.data objectAtIndex:rowIndex];
NSString *columnIdentifier = [aTableColumn identifier];
return [row objectForKey:columnIdentifier];
}
You'll notice we are using the column identifier here. Normally you set this value in Interface Builder on the table column. In the case above the identifier needs to be the same as the key in the dictionary for which you wish to display information.
Finally allowing the user to set a value of a column in the table view:
-(void)tableView:(NSTableView *)aTableView setObjectValue:(id)anObject forTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger) rowIndex
{
NSDictionary *row = [self.data objectAtIndex:rowIndex];
NSString *columnIdentifier = [aTableColumn identifier];
[row setValue:anObject forKey:columnIdentifier];
}
I have a program that changes the data of a table (among other things). In a function (specifically when triggered by a button), I have the code below, but it says, "use of undeclared identifier 'tableView' ". However, outside of this, I have this run when I start the program, and it works.
- (id)tableView:(NSTableView *)aTableView objectValueForTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex {
if ([aTableColumn.identifier isEqualToString:#"row1"]){
return everything2[rowIndex];
}
return everything[rowIndex];
}
I was watching a tutorial and I don't remember everything I did, so do I have to declare, delegate, link the function, or something else?
This is the declaration of everything(2):
NSString *everything[115];
NSString *everything2[115];
I am currently going through the 3rd Edition of the Mac OSX Cocoa book from the Big Nerd Ranch guys and I am editing my program to include table views. Here the code from the AppController.m file where I have to implement the required protocol methods from the TableView:
-(id)init{
self = [super init];
voiceArray = [NSSpeechSynthesizer availableVoices];
speechSynth = [[NSSpeechSynthesizer alloc] initWithVoice:nil];
[speechSynth setDelegate:self];
return self;
}
-(int)numberOfRowsInTableView:(NSTableView *)tv{
NSLog(#"Getting number of rows in table view: %lu", [voiceArray count]);
return [voiceArray count];
}
-(id)tableView:(NSTableView *)tv objectValueForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row{
NSString *v = [voiceArray objectAtIndex:row];
NSDictionary *dict = [NSSpeechSynthesizer attributesForVoice:v];
NSLog(#"Voice Name %#", [dict objectForKey:NSVoiceName]);
return [dict objectForKey:NSVoiceName];
}
-(void)tableViewSelectionDidChange:(NSNotification *)notification{
int row = [tableView selectedRow];
NSLog(#"row selected %d", row);
if(row == 1){
return;
}
NSString *selectedVoice = [voiceArray objectAtIndex:row];
[speechSynth setVoice:selectedVoice];
NSLog(#"new voice %# ", selectedVoice);
}
When the app first loads I get the following output:
2012-05-27 15:02:29.040 Speakline[42836:f03] Getting number of rows in
table view: 24 2012-05-27 15:02:29.042 Speakline[42836:f03] row
selected 2 2012-05-27 15:02:29.043 Speakline[42836:f03] new voice
com.apple.speech.synthesis.voice.Alex 2012-05-27 15:02:29.162
Speakline[42836:f03] Voice Name Agnes 2012-05-27 15:02:29.163
Speakline[42836:f03] Voice Name Albert
I want to make sure I understand fully what is going on here. In order to do this I have a couple of questions.
It looks like the numberOfRowsInTableView: method was automatically called after the init method. Is this correct?
How often does objectValueForTableColumn: get called? What events prompt that method to get called? Also, in the code there, the return statement confused me. Where exactly does this return value go?
As a side note they wanted me to connect the Outlets and the AppController via control+clicking (via the connections panel) and linking them in that way. What alternatives are there avaialble for connecting delegates and datasources to different kinds of views without doing this? I am assuming that adding NSTableViewDelegate in the controller header file might be one way. If you have the option of control+click connecting all your views to outlets and so on vs programmatically setting it all up is it just a matter of preference at this point? It just seems to me that in order to understand what is going on it might be better to just write the code yourself.
1) Both numberOfRowsInTableView and objectValueForTableColumn:Row: get called soon after the nib is unarchived (I'm not sure of the exact order of things), so the table view can be populated with data.
2) The loading of the table and reloading or adding new data as well as scrolling will cause objectValueForTableColumn:row: to be called (by the table view). It gets called for each row that is populated. The value goes to the table view, that's how it gets its data.
3) The other way to connect delegates is to do it in code with setDelegate:, but putting NSTableViewDelegate in the .h file does not do that -- that's just a promise to the compiler that you will implement some or all of the delegate messages.
I have a simple NSTableView which I have loaded with data from a NSMutableArray. When I select a row (entry) in the tableView and modify it, I can find the row index, what I cannot get is the edited entry out as a string so I can modify the array. I can find lots of information on selecting rows, etc., but not on how to get the actual modified string. I keep thinking this should be real simple. Help please.
Part of my code:
- (IBAction)toDoEdit:(id)sender // Accept the edited data
{
NSString *toDoItem = [[toDoTableCell:toDoTableView dataCellFoTableColumn:0 row:rowToBeEdited] stringValue];
// I get the error "dataCellForTableColumn' method cannot be found.
[toDoArray replaceObjectAtIndex:rowToBeDeleted withObject:toDoItem];
[toDoTableView reloadData];
[toDoTableView deselectRow:rowToBeDeleted];
}
~~~~~~~~~~~
// This method should return the cell value of the selected row
- toDoTableCell:(NSTableView *)tableView dataCellForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row
{
return toDoTableCell; // No errors here but toDoTableCell is nil.
}
The 'Add' data to tableView works, 'Delete' data from tableView works, I just cannot get the edited data out of tableView so I can reload the data with the corrections.
What you are looking for is an NSTableView Delegate method:
- (NSCell *)tableView:(NSTableView *)tableView dataCellForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row
This will return the NSCell that is in the row and column that you specify. From the NSCell you should be able to extract the value that you need. Depending on how you are using your NSCell you would either call [cell stringValue] or [cell objectValue].
Try this:
– tableView:setObjectValue:forTableColumn:row:
in - NSTableViewDataSource Protocol Reference
--- Edited based on comment ---
Above method is called whenever user tries to edit a table row, it also provides user with changed value as parameter. If you are trying to edit the row in table itself then it should serve your purpose. You can simply check the objectValue obtained as parameter and verify if it is correct or not. In case it is incorrect you can modify the obtained value and set it in todoArray.
Briefly:
- (void)tableView:(NSTableView *)aTableView setObjectValue:(id)anObject forTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex
{
// below case is an example, you can add your own
if([anObject isEqualToString:#"Incorrect"])
{
anObject = #"Correct";
}
// Considering todoArray is array of dictionary items containing keys as table-column identifiers
NSMutableDictionary *originalData = [todoArray objectAtIndex:rowIndex];
[originalData setValue:anObject forKey:[aTableColumn identifier]];
[toDoTableView reloadData];
}
To get the value being edited you can simply use this code in above method, before setting the new value:
NSString *editedValue = [[todoArray objectAtIndex:rowIndex] valueForKey:[aTableColumn identifier]];
Hope this helps :)
It is simple. Read up on Cocoa Bindings and NSArrayController.
Take a look at the NSTableView methods selectedColumn, selectedColumnIndexes, selectedRow and selectedRowIndexes. I guess they should provide you with the needed information.
Now you can query the model, i.e. the array, for the data you need.
I have a NSMutableDictionary as the datasource for my UITableView. I am trying to implement the delete mode and having an issue.
I am logging the key I am trying to remove as well as the object that it corresponds to as this issue seems like it might be related to my trying to access unallocated memory or something. Here is my implementation of tableView:commitEditionStyle:forRowAtIndexPath:
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source.
NSArray * keys = [userList allKeys];
NSNumber *keyToRemove = [keys objectAtIndex:indexPath.row];
NSLog(#"Key to remove: %#",keyToRemove);
NSLog(#"Object at key: %#",[userList objectForKey:keyToRemove]);
[userList removeObjectForKey:keyToRemove];
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
[keys release];
[keyToRemove release];
}
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.
}
}
This method runs and then I get the error. The two NSLog statements output the correct key and it's corresponding value.
Can someone tell me what I'm doing wrong?
Thanks
You don't own keys or keysToRemove, so you should not be releasing them. I strongly suggest reading up on the Cocoa memory management rules.
Here's your problem:
[keys release];
[keyToRemove release];
You are releasing keys and keyToRemove, even though you never allocated it, retained it, or copied it, so it's reference count is decreasing more than it should.
As a general rule, you should only release an object if you called alloc, retain (not init, sorry) or copy on it, I recommend you read on reference counting here: Practical Memory Management