NSPageController tutorial for Cocoa on OS X

Question

I need to use NSPageController in some project but I have no idea how it works, does anybody have time for some simple tutorial to show me because the documentation isn't helping me.

Forgot to mention: I'm working on Mac project (NOT iOS)

Answer 1

Simple NSPageController book mode tutorial

Create new Cocoa Application-project. Open MainMenu.xib in interface builder and add Image Well and Label objects to your application window. Also add Page Controller object.

Set Page Controller's view to point Image Well.

---

Add some images to Images.xcassets

I used three images in this sample project:

• first.png
• second.png
• third.png

---

MyAppDelegate.h

Add referencing outlets for Page Controller, Label and Image Well. Set MyAppDelegate as NSPageControllerDelegate and add also NSArray for images. After this your MyAppDelegate.h file should look like this:

@interface MyAppDelegate : NSObject <NSApplicationDelegate, NSPageControllerDelegate>

@property (assign) IBOutlet NSWindow *window;
@property (unsafe_unretained) IBOutlet NSPageController *pageController;
@property (weak) IBOutlet NSImageView *imageView;
@property (weak) IBOutlet NSTextField *infoLabel;

@property (nonatomic) NSArray *imageArray;

@end

---

MyAppDelegate.m

Some initialization:

- (void)awakeFromNib {
    _imageArray = @[ [NSImage imageNamed:@"first"],
                     [NSImage imageNamed:@"second"],
                     [NSImage imageNamed:@"third"]];
    
    /* Set delegate for NSPageControl */
    [_pageController setDelegate:self];
    /* Set arranged objects for NSPageControl */
    [_pageController setArrangedObjects:_imageArray];
    /* Set transition style, in this example we use book style */
    [_pageController setTransitionStyle:NSPageControllerTransitionStyleStackBook];
    
    /* Set info label's text */
    NSString *info = [NSString stringWithFormat:@"Image %ld/%ld", ([_pageController selectedIndex]+1), [_imageArray count]];
    [_infoLabel setStringValue:info];
}

Page Controller delegate methods:

- (void)pageController:(NSPageController *)pageController didTransitionToObject:(id)object {
    /* When image is changed, update info label's text */
    NSString *info = [NSString stringWithFormat:@"Image %ld/%ld", ([_pageController selectedIndex]+1), [_imageArray count]];
    [_infoLabel setStringValue:info];
}

- (NSString *)pageController:(NSPageController *)pageController identifierForObject:(id)object {
    /* Returns object's array index as identiefier */
    NSString *identifier = [[NSNumber numberWithInteger:[_imageArray indexOfObject:object]] stringValue];
    return identifier;
}

- (NSViewController *)pageController:(NSPageController *)pageController viewControllerForIdentifier:(NSString *)identifier {
    /* Create new view controller and image view */
    NSViewController *vController = [NSViewController new];
    NSImageView *iView = [[NSImageView alloc] initWithFrame:[_imageView frame]];
    
    /* Get image from image array using identiefier and set image to view */
    [iView setImage:(NSImage *)[_imageArray objectAtIndex:[identifier integerValue]]];
    /* Set image view's frame style to none */
    [iView setImageFrameStyle:NSImageFrameNone];
    
    /* Add image view to view controller and return view controller */
    [vController setView:iView];
    return vController;
}

---

And it's done

---

If your _pageController is null/nil

Connect your Page Controller to _pageController by pressing ctrl and dragging with mouse to _pageController in MyAppDelegate.h file.