Snow Leopard has introduced a new BSD-level infrastructure, with simple and efficient API to do this job. Here a little usage preview.

Block objects are a C-based language feature that you can use in your C, Objective-C, and C++ code. Blocks make it easy to define a self-contained unit of work. Blocks are something like Actions (delegate {}) in C#. Very useful to embed function in loops.

Blocks looks like a “private” function pointer, but you can access to the “parent” vars. (If you’re a Python coder, you’ve exactly the same thing).

/* Blocks in Python...
 * def main():
 *    a = 10
 *    def test(k):
 *        print a, k
 *    test(128)
 */
int main (int argc, const char *argv[]) {
  int a = 12;

  void (^test_block) (int) = ^(int k) {
    printf("A Block: PARENT(%d) ARG(%d)\n", a, k);
  };

  test_block(128);

  return 0;
}

The GCD queue API provides dispatch queues from which threads take tasks to be executed. Because the threads are managed by GCD, Mac OS X can optimize the number of threads based upon available memory, number of currently active CPU cores, and so on. This shifts a great deal of the burden of power and resource management to the operating system itself, freeing your application to focus on the actual work to be accomplished.

#include <dispatch/dispatch.h>
#include <stdlib.h>
#include <stdio.h>

#define ITEM_VMIN       (1)
#define ITEM_VMAX       (200)
#define NR_ITEMS        (100)

static void __fill_item (void *items, size_t n) {
  int *i_items = (int *)items;
  i_items[n] = (ITEM_VMIN + (int)(ITEM_VMAX * ((double)rand() / RAND_MAX)));
}

static void __work_on_item (void *items, size_t n) {
  int *i_items = (int *)items;
  i_items[n] *= 100;  /* Do some Computation on this Item */
}

int main (int argc, const char *argv[]) {
  dispatch_queue_t queue;
  int data[NR_ITEMS];

  /* Get Global Dispatch Queue */
  queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);

  /* Initialize data Elements, and run computation on each element */
  dispatch_apply_f(NR_ITEMS, queue, data, __fill_item);
  dispatch_apply_f(NR_ITEMS, queue, data, __work_on_item);

  /* Brief review of the items */
  dispatch_apply(NR_ITEMS, queue, ^(size_t n) {
    printf("Results: Item %lu = %d\n", n, data[n]);
  });

  return 0;
}

Ok, It’s one week later… but I’ve installed it just right now. Maybe tomorrow morning an usage example of Grand Central Dispatch.

Joel asked me to revise the Sidebar, allowing to add/remove and do other operation at any time.

I’ve rewritten all the code of the Sidebar, and I’ve added a couple of new features, like the default action handler and obviously the ability to add, remove items and badges at any time.

All the past features, like Drag & Drop are still present, but there’s something else to do to improve it. If You’ve suggestions, patches or something else post a comment or send me a mail!

The Source Code is Available Here: Cocoa Sidebar 2 Source Code.

Update 10 March 2008 – Source Updated with Fixes.

You can find the source code here: Drag & Drop Test Source Code.

The interesting part of this example is How to manage WebKit content, and how to add something dynamically.

I use webView:decidePolicyForNavigationAction:request:frame:decisionListener: of WebPolicyDelegate Protocol to handle my custom requests, in this way…

- (void)webView:(WebView *)sender
    decidePolicyForNavigationAction:(NSDictionary *)actionInformation
   request:(NSURLRequest *)request frame:(WebFrame *)frame
   decisionListener:(id)listener
{
    if ([[[request URL] path] isEqualToString:@"PATH to Handle"]) {
        [listener ignore];
        // Handle Request
    } else {
         [listener use];
    }
}

…Then with a little bit of JavaScript I’ll set my dynamic content loaded from Database or somewhere else.

NSArray *args = [NSArray arrayWithObjects:@"Item1Content",
                                  @"Hi, I'm Test 1 Content", nil];
[[webKit windowScriptObject] callWebScriptMethod:@"fillElement"
                               withArguments:args];

The fillElement method is a simple JS function like this document.getElementById(elem).innerHTML = data;

Here you can find the Source Code.

Cocoa Sidebar

You can find the example Source Code Here.

And below you can see hot to add folders, nodes and set badges.

- (void)populateOutlineContents:(id)inObject {
  NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

  [sidebar addRootFolder:@"1" name:@"DEVICES"];
  [sidebar addChild:@"1.1" name:@"Machintosh HD"
               icon:[NSImage imageNamed:NSImageNameComputer]
             action:@selector(buttonPres:) target:self];

  [sidebar addRootFolder:@"2" name:@"PLACES"];
  [sidebar addChild:@"2.1"
                url:NSHomeDirectory()
             action:@selector(buttonPres:) target:self];

  [sidebar addRootFolder:@"3" name:@"OTHER."];
  [sidebar addChild:@"3.1" name:@"Bonjour"
               icon:[NSImage imageNamed:NSImageNameBonjour]
             action:@selector(buttonPres:) target:self];
  [sidebar addChild:@"3.2" name:@"Users"
               icon:[NSImage imageNamed:NSImageNameUserGroup]
             action:@selector(buttonPres:) target:self];

  [sidebar clearSelection];

  // Add Badge to Node with Key
  [sidebar setBadge:@"2.1" count:5];
  [sidebar setBadge:@"3.2" count:7];

  [pool release];
}

- (void)buttonPres:(id)sender {
  NSLog(@"Button Press %@", [sender nodeTitle]);
}

Here you can find the Mac Example Source Code and the iPhone Example Source Code.

This is a simple usage example:

Sqlite *sqlite = [[Sqlite alloc] init];

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                             NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *writableDBPath = [documentsDirectory
                        stringByAppendingPathComponent:@"SQLiteTest.db"];
if (![sqlite open:writableDBPath])
  return;

[sqlite executeNonQuery:@"CREATE TABLE test (key TEXT NOT NULL, value TEXT);"];
[sqlite executeNonQuery:@"DELETE FROM test;"];
[sqlite executeNonQuery:@"INSERT INTO test VALUES (?, ?);",
                        [Sqlite createUuid], @"PROVA"];
[sqlite executeNonQuery:@"INSERT INTO test VALUES (?, ?);",
                         [Sqlite createUuid], @"PROVA 2"];
[sqlite executeNonQuery:@"INSERT INTO test VALUES (?, ?);",
                         [Sqlite createUuid], @"PROVA 3"];

NSArray *results = [sqlite executeQuery:@"SELECT * FROM test;"];
for (NSDictionary *dictionary in results) {
  NSLog(@"Row");
  for (NSString *key in [dictionary keyEnumerator])
      NSLog(@" - %@ %@", key, [dictionary objectForKey:key]);
}

[results release];
[sqlite release];

I’ve made a simple example that you can see below where I’ve used custom NSView that draws an Image and a Bezier Path with some text inside, and around the Bezier Path there’s a Shadow.

Cocoa Drawing Example

…And this is the drawRect method source code of the custom NSView.

- (void)drawRect:(NSRect)frameRect {
  [NSGraphicsContext saveGraphicsState];

  [[NSColor colorWithCalibratedRed:0.64 green:0.66 blue:0.71 alpha:1.0] set];
  NSRectFill(frameRect);

  /* Draw Shadow */
  NSShadow *shadow = [[NSShadow alloc] init];
  [shadow setShadowColor:[[NSColor blackColor] colorWithAlphaComponent:0.5]];
  [shadow setShadowOffset:NSMakeSize(4.0, -4.0)];
  [shadow setShadowBlurRadius:3.0];
  [shadow set];

  /* Draw Control */
  NSRect myRect = NSMakeRect(80, 50, frameRect.size.width - 120, 60);
  NSBezierPath *path = [NSBezierPath bezierPath];
  [path setLineJoinStyle:NSRoundLineJoinStyle];
  [path appendBezierPathWithRoundedRect:myRect xRadius:8.0 yRadius:8.0];    

  [path moveToPoint:NSMakePoint(80, 75)];
  [path lineToPoint:NSMakePoint(65, 85)];
  [path lineToPoint:NSMakePoint(80, 95)];

  NSColor *startingColor = [NSColor colorWithCalibratedRed:0.90
                                             green:0.92 blue:0.85 alpha:1.0];
  NSColor *endingColor = [NSColor colorWithCalibratedRed:0.81
                                           green:0.83 blue:0.76 alpha:1.0];
  NSGradient *gradient = [[[NSGradient alloc] initWithStartingColor:startingColor
                                 endingColor:endingColor] autorelease];
  [path fill];
  [gradient drawInBezierPath:path angle:90];

  [NSGraphicsContext restoreGraphicsState];

  [shadow release];

  NSImage *image = [NSImage imageNamed:NSImageNameUser];
  [image drawInRect:NSMakeRect(15, 50, 50, 50) fromRect:NSZeroRect
                operation:NSCompositeSourceOver fraction:1.0];

  NSString *string = [NSString stringWithString:@"Text\nMore Text"];
  [string drawInRect:NSMakeRect(90, 60, frameRect.size.width - 140, 45)
                        withAttributes:nil];
}

Cocoa Filterbar Demo

Below, I’ve added a movie… but it doesn’t [sizeToFit] the page… so here is the link of Cocoa Filterbar Demo. And here you can find the Cocoa Filterbar Souce.

Example: Cocoa Horizontal Box

This is the HBox Source…

@interface HBox : NSView {
    NSUInteger hspace;
}

@property (readwrite, assign) NSUInteger space;

- (id)initWithFrame:(NSRect)frameRect;

- (void)clearItems;

- (void)addItem:(NSControl *)itemView;
- (void)removeItemAtIndex:(NSUInteger)index;

- (void)moveItem:(NSView *)view space:(NSInteger)space;
- (void)moveItems:(NSInteger) space fromIndex:(NSUInteger)index;
@end

@implementation HBox

@synthesize space = hspace;

- (id)initWithFrame:(NSRect)frameRect {
    if ((self = [super initWithFrame:frameRect])) {
        hspace = 4;
    }
    return self;
}

- (void)dealloc {
    [super dealloc];
}

- (void)clearItems {
    NSArray *subviewArray = [self subviews];
    NSUInteger subviewCount = [subviewArray count];

    while (subviewCount-- > 0) {
        NSView *view = [subviewArray objectAtIndex:0];
        [view removeFromSuperview];
        [view release];
    }

    [self setNeedsDisplay:YES];
}

- (void)removeItemAtIndex:(NSUInteger)index {
    NSView *view = [[self subviews] objectAtIndex:index];
    int viewWidth = -1 * [view frame].size.width - hspace;
    [view removeFromSuperview];
    [view release];

    [self moveItems:viewWidth fromIndex:index];
    [self setNeedsDisplay:YES];
}

- (void)moveItem:(NSView *)view space:(NSInteger)space {
    NSRect rect = [view frame];
    rect.origin.x += space;
    [view setFrame:rect];
}

- (void)moveItems:(NSInteger) space fromIndex:(NSUInteger)index {
    NSArray *subviewArray = [self subviews];
    NSUInteger subviewCount = [subviewArray count];

    for (; index < subviewCount; ++index)
        [self moveItem:[subviewArray objectAtIndex:index] space:space];
}

- (void)addItem:(NSControl *)itemView {
    [itemView sizeToFit];

    NSRect itemFrame = [itemView frame];
    NSView *lastView = [[self subviews] lastObject];
    if (lastView != nil) {
        itemFrame.origin.x = [lastView frame].origin.x +
                             [lastView frame].size.width +
                             hspace;
    } else {
        itemFrame.origin.x = [self bounds].origin.x + hspace;
    }
    itemFrame.origin.y = [self bounds].origin.y;
    [itemView setFrame:itemFrame];

    [self addSubview:itemView];
    [self setNeedsDisplay:YES];
}

@end

And This is a simple “Main” to test the HBox.

- (NSTextField *)createTextField:(NSString *)text {
    NSTextField *field = [[NSTextField alloc] init];
    [field setStringValue:text];
    return [field retain];
}

- (NSButton *)createButton:(NSString *)caption {
    NSButton *button = [[NSButton alloc] init];
    [button setBezelStyle:NSRecessedBezelStyle];
    [button setButtonType:NSPushOnPushOffButton];
    [[button cell] setHighlightsBy:(NSCellIsBordered | NSCellIsInsetButton)];
    [button setShowsBorderOnlyWhileMouseInside:YES];
    [button setButtonType:NSOnOffButton];
    [button setTitle:caption];

    return [button retain];
}

- (void)awakeFromNib {
    [box addItem:[self createTextField:@"Label 1"]];
    [box addItem:[self createButton:@"Button 1"]];
    [box removeItemAtIndex:0];
    [box addItem:[self createTextField:@"Label 2"]];
    [box addItem:[self createButton:@"Say"]];
}

Download Here the Test Cocoa HBox Source.

Quick Look Example

Here you can Find the source code example: TestQuickLook.zip

So, I don’t have some code to publish now, but i’ve made a couple of screenshots that contain some of Cocoa’s Controls.

Cocoa Controls

Ok… thanks for this Gallery, but it will be helpful have olso Objects Type….

Cocoa Controls - Interface Builder

And… last thing, different types of Windows.

Cocoa (HUD, Textured, Panel) Window