CheckBox in tableview

Question

Hai all, I am facing a trouble in putting check boxes into a table view. I am posting a part of my code here..

- (NSCell *)tableView:(NSTableView *)tableView dataCellForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row
{
    NSButtonCell *cell=[[NSButtonCell alloc] init];
    NSString *strDisplayPlaylistName;
    strDisplayPlaylistName=[playListNameArray objectAtIndex:row];
    [cell setTitle:strDisplayPlaylistName];
    [cell setAllowsMixedState:YES];
    [cell setButtonType:NSSwitchButton];
    return cell; 
}


- (void)tableView:(NSTableView *)aTableView setObjectValue:(id)anObject forTableColumn:(NSTableColumn *)aTableColumn row:(NSInteger)rowIndex {       
    NSCell *aCell = [aTableColumn dataCellForRow:rowIndex];
    [aCell setNextState];
    //NSCell *aCell=[aAddedCells objectAtIndex:rowIndex];
    //[aCell setNextState];
}

I got the checkboxes inside the tableview..But the problem is that I cant uncheck the buttons . Is trhere anything more to do ..I am new in cocoa Programming..Please any one give me a solution..

Answer 1

You're missing a couple important peices. You need to update you're model (data stcuture) in response to the tableValue:setObjectValue:forTableColumn:row: message, so that you can correctly return the new value from tableView:objectValueForTableColumn:row: method.

Here are some table data source methods assuming you have a 'myRows' array filled with objects with a 'booleanAttribute' property.

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

- (id)tableView:(NSTableView *)tableView objectValueForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row {
    BOOL value = [[myRows objectAtIndex:row] booleanAttribute];
    return [NSNumber numberWithInteger:(value ? NSOnState : NSOffState)];
}

- (void)tableView:(NSTableView *)tableView setObjectValue:(id)value forTableColumn:(NSTableColumn *)column row:(NSInteger)row {          
    [[myRows objectAtIndex:row] setBooleanAttribute:[value booleanValue]];
}

You should also setup your table cell in interface builder. You can drag a button cell configured like a standard check box directly onto one of your table columns.

Answer 2

I'm not sure why you're creating the cell in code. You can just drag the cell onto the table column in Interface Builder.

Also, setObjectValue: is where you respond to the change in the cell's state. The user has already changed the cell's state to off; then you send setNextState and change it back. That's why the cell doesn't appear to uncheck: you keep re-checking it.

What you need to do is not touch the cell at all, but set the object value (which, for this column, will probably be a Boolean NSNumber containing either YES or NO) as the new value of the appropriate property in your model.

Also, of course, make sure the column is set as editable.