非法的NSTableView数据源-我错了什么？

Question

我有一个应用程序，在其中添加了带有电影名称的简单图像（海报）。但是运行后，我只能在控制台中看到一个空表和一个错误：

  

非法的NSTableView数据源（）。必须实现numberOfRowsInTableView：和tableView：objectValueForTableColumn：row：

现在，在我的.xib文件中，我具有dataSource和delegate链接到File's Owner的表视图。这是代码：

MasterViewController.m

#import "MasterViewController.h"
#import "NSObject+IntengineMovieData.h"
#import "NSObject+IntengineMovieDoc.h"

@interface MasterViewController ()

@end

@implementation MasterViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do view setup here.
}

- (NSView *)tableView:(NSTableView *)tableView objectValueForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row {
    NSTableCellView *cellView = [tableView makeViewWithIdentifier:tableColumn.identifier owner:self];

    if([tableColumn.identifier isEqualToString:@"MoviesColumn"]) {
        IntengineMovieDoc *movieDoc = [self.movies objectAtIndex:row];
        cellView.imageView.image = movieDoc.thumbImage;
        cellView.textField.stringValue = movieDoc.data.title;
        return cellView;
    }
    return cellView;
}

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

@end

该问题是什么意思，我该如何解决？

---

编辑1：我有MasterViewController.xib作为我的主界面。我是这样加载的：

AppDelegate.m

#import "AppDelegate.h"
#import "NSObject+IntengineMovieDoc.h"
#include "MasterViewController.h"

@interface AppDelegate ()
@property (nonatomic, strong) IBOutlet MasterViewController *masterViewController;
@property (assign) IBOutlet NSWindow *window;
@end

@implementation AppDelegate

- (void)applicationDidFinishLaunching:(NSNotification *)aNotification {
    self.masterViewController = [[MasterViewController alloc]
                                 initWithNibName:@"MasterViewController" bundle:nil];

    IntengineMovieDoc *movie1 = [[IntengineMovieDoc alloc] initWithTitle:@"The Godfather" rating:5 thumbImage:[NSImage imageNamed:@"TheGodfatherThumb.jpg"] fullImage:[NSImage imageNamed:@"TheGodfather.jpg"]];

    IntengineMovieDoc *movie2 = [[IntengineMovieDoc alloc] initWithTitle:@"Tree of Life" rating:4 thumbImage:[NSImage imageNamed:@"TreeOfLifeThumb.jpg"] fullImage:[NSImage imageNamed:@"TreeOfLife.jpg"]];

    IntengineMovieDoc *movie3 = [[IntengineMovieDoc alloc] initWithTitle:@"Taxi Driver" rating:5 thumbImage:[NSImage imageNamed:@"TaxiDriverThumb.jpg"] fullImage:[NSImage imageNamed:@"TaxiDriver.jpg"]];

    NSMutableArray *movies = [NSMutableArray arrayWithObjects: movie1, movie2, movie3, nil];
    self.masterViewController.movies = movies;

    [self.window.contentView addSubview:self.masterViewController.view];
    self.masterViewController.view.frame = ((NSView*)self.window.contentView).bounds;
}

- (void)applicationWillTerminate:(NSNotification *)aNotification {
    // Insert code here to tear down your application
}
@end