Question

I’m working on learning Objective-C/Coaoa, but I’ve seem to have gotten a bit stuck with getting the NSTableView object to work for me. I’ve followed all the directions, but for some reason I still get this error:

Class 'RobotManager' does not implement the 'NSTableViewDataSource' protocol

Here’s my source, tell me what you see is wrong here, I’m about to tear my face off.

RobotManager.h

@interface RobotManager : NSObject {
 // Interface vars
 IBOutlet NSWindow *MainWindow;
 IBOutlet NSTableView *RobotTable;
 NSMutableArray *RobotList;
}

- (int) numberOfRowsInTableView: (NSTableView*) tableView;
- (id) tableView:(NSTableView *) tableView objectValueForTableColumn:(NSTableColumn *)tableColumn row:(int)rowIndex;
@end

RobotManager.m

#import "RobotManager.h"

@implementation RobotManager

-(void) awakeFromNib {
 // Generate some dummy vals
 [RobotList addObject:@"Hello"];
 [RobotList addObject:@"World"];
 [RobotTable setDataSource:self]; // This is where I'm getting the protocol warning
 [RobotTable reloadData];
}

-(int) numberOfRowsInTableView: (NSTableView *) tableView {
 return [RobotList count];
}

-(id) tableView:(NSTableView *) tableView objectValueForTableColumn:(NSTableColumn *)tableColumn row:(int)rowIndex {
 return [RobotList objectAtIndex:rowIndex];
}

@end

I’m running OS X 10.6.1 if that makes any difference. Thanks in advance.

Answer 1

Try changing the declaration of the @interface to the following:

@interface RobotManager : NSObject <NSTableViewDataSource> {

This will tell the compiler that the RobotManager class follows the NSTableViewDataSource protocol.

Edit:

In addition, it’s probably likely that the RobotList is not being initialized before the two methods of NSTableViewDataSource are being called. In otherwords, awakeFromNib is not being called.

Unless there is an explicit call to the awakeFromNib from some caller, the RobotList won’t be initialized, so rather than populating the RobotList in that method, try populating it when the RobotManager is first instantiated.