What's interesting is that cells actually have references to separator views. Just open UITableViewCell.h file and look at cell's ivars; it has

    UIView *_separatorView;
    UIView *_topSeparatorView;

which are clearly bottom and top separator views for the cell. I don't know why Apple does not expose them or does not allow to customize them in some way—it could have saved so much time…

So what could be done to alleviate this? How could we provide our own custom separators? The easiest solution (and I guess that's what most devs do) is to set separatorStyle to 'no separators' and add custom separator views to the content view of every cell. It works, but not that well. First you have to hide top separator view for each cell except the one at the bottom and what's most important these views are resized when table is being edited.

Another solution which I provide here is to add separators as cells. I've written a special table provider that wraps your provider (data source + delegate) and inserts these cells. Below is an API of this provider:

enum {
	BACellSeparatorPositionNone = 0,
	BACellSeparatorPositionTop = 1 << 0,
	BACellSeparatorPositionBottom = 1 << 1
};

typedef NSUInteger BACellSeparatorPositions;

@protocol BASeparatedTableProviderDelegate
    <NSObject, UITableViewDataSource, UITableViewDelegate>

- (BACellSeparatorPositions)tableView:(UITableView *)tableView
    separatorPositionsForRow:(NSIndexPath *)indexPath;

- (UITableViewCell *)tableView:(UITableView *)tableView
    topSeparatorCellForRowAtIndexPath:(NSIndexPath *)indexPath;

- (UITableViewCell *)tableView:(UITableView *)tableView
    bottomSeparatorCellForRowAtIndexPath:(NSIndexPath *)indexPath;

- (CGFloat)tableView:(UITableView *)tableView
    heightForTopSeparatorRowAtIndexPath:(NSIndexPath *)indexPath;

- (CGFloat)tableView:(UITableView *)tableView
    heightForBottomSeparatorRowAtIndexPath:(NSIndexPath *)indexPath;

@end

@interface BASeparatedTableProvider : NSObject
    <UITableViewDataSource, UITableViewDelegate>

@property(nonatomic, assign) id<BASeparatedTableProviderDelegate> delegate;

- (NSIndexPath *)separatedIndexPathForIndexPath:(NSIndexPath *)indexPath;
- (NSArray *)separatedIndexPathsForIndexPaths:(NSArray *)indexPaths;

@end

So all that you have to do is to implement five methods that provide separator positions for the cell, their views and heights. In most cases top and bottom separators are the same so effectively you have to add code just to create the custom separator cell.

Class BASeparatedTableProvider is part of the BaseAppKit framework but does not depend much on other classes so you can just copy it into your project. Not all methods are implemented yet; you should be able to show table contents and edit it but some delegate methods just won't be called.

I was not sure about performance of this approach and its feasibility but so far it works well. I'm using this code in production and there seems to be no issues with it.

I have two daughters (2 and 4 years old) and actually many of the UI decisions were made by watching them using the app. For example the biggest issue with many apps for kids is that they have on-screen controls to change preferences or share something and children often get stuck with this. I made a decision to remove any such buttons; you have to make a pinch gesture to show bars with navigation and other controls.

[ DOWNLOAD APP ]

I also have some promo codes to share:

• WF9KRMJFPENK
• HMF63K66PJLY
• F34L4K9H79RK
• JMLY7YJ4MTLP
• KXJR33RFWAY9

Here is also the first review of the app.

P.S.

If you are an artist and interested in publishing your drawings or story for iPad please drop me a letter. I'm looking for more content for the project.

It looks like Automagic Coding is just doing so. I've just stalked the code and have not used it yet but I guess I'll give it a try on the next occasion. So far it seems pretty powerful and I guess it will save me some routine coding.

It's customizable; you can provide these two images to completely change the theme of the control:

As selected segment got changed the BASequenceControl sends UIControlEventValueChanged event just like the UISegmentedControl.

The first step is to add Twitter framework to the project. You do it as usual but change 'Required' setting to 'Optional' so if the framework is not available the app will be able to start anyway.

Next in your view controller import <Twitter/Twitter.h> and add the following method:

- (IBAction)tweet:(NSString *)text image:(UIImage *)image {
  if ([TWTweetComposeViewController canSendTweet]) {
    TWTweetComposeViewController *controller =
      [[[TWTweetComposeViewController alloc] init] autorelease];
    [controller setInitialText:text];
    if (image) {
      [controller addImage:image];
    }
    [self presentModalViewController:controller animated:YES];
  }
}

It will work on iOS 5 but won't on earlier versions and the reason is that we try to load TWTweetComposeViewController class and fail to do so. What we should do is to remove the direct reference to it and load it in a 'safe' way:

- (IBAction)tweet:(NSString *)text image:(UIImage *)image {
  Class cclass = NSClassFromString(@"TWTweetComposeViewController");
  if (cclass && [cclass canSendTweet]) {
    id controller = [[[cclass alloc] init] autorelease];
    [controller setInitialText:text];
    if (image) {
      [controller addImage:image];
    }
    [self presentModalViewController:controller animated:YES];
  }
}

This second implementation will work on any iOS version. The same approach could be used in all other cases when you have to make use of some new iOS feature and stay compatible with previous releases.

I'm also playing with InstallWall and AppCircle; so far I can't say that they were a great success but let's see how it goes.

If you know some other services to promote or monetize the app I'd be happy to try...

The first class, DataBagX, is the class that I would have written in 2008. Note that there is no special syntax for properties: you have to define instance variables, getters and setters. What you call property is a pure naming convention; you have to analyze public methods to figure out that there are two properties: prop1 and prop2.

What many people really hate about this approach to class definition is that instance variables are exposed in public interface file. It's not just wrong logically because you reveal implementation details but you also have to add forward class definitions for contained objects or include their header files, which are completely irrelevant to the clients of the class being defined.

The positive side of such definition is simplicity—you don't have to know much of the language to understand what's going on. Here are instance variables, and there are methods that work with them.

DataBagX.h

@interface DataBagX : NSObject {
@private
  int _prop1;
  double _prop2m;
}

- (int)prop1;
- (void)setProp1:(int)prop1;
- (double)prop2;
- (void)setProp2:(double)prop2;

@end

DataBagX.m

#import "DataBagX.h"

@implementation DataBagX

- (int)prop1 {
  return _prop1;
}

- (void)setProp1:(int)prop1 {
  _prop1 = prop1;
}

- (double)prop2 {
  return _prop2m / 2;
}

- (void)setProp2:(double)prop2 {
  _prop2m = prop2 * 2;
}

@end

Fast forward to 2011: here is the same class rewritten using the new language features. The most noticeable thing is that interface contains just necessary information in a very compact form. We have two properties? So here they are: just a keyword of property definition, type and name. All the implementation details go into implementation file.

And implementation is quite spectacular too: for ordinary properties it's just enough to synthesize it in one line. Also note how definition of instance variables is possible in implementation file, right where it should be from the beginning.

DataBagY.h

#import 

@interface DataBagY : NSObject

@property int prop1;
@property double prop2;

@end

DataBagY.m

#import "DataBagY.h"

@implementation DataBagY {
@private
  double _prop2m;
}

@synthesize prop1 = _prop1;

- (double)prop2 {
  return _prop2m / 2;
}

- (void)setProp2:(double)prop2 {
  _prop2m = prop2 * 2;
}

@end

These are just several improvements that you will encounter most frequently but change class definitions quite dramatically. I'd recommend you to watch WWDC 2011 videos to learn more about the Objective-C and "Session 322 - Objective-C Advancements in Depth" in particular.

- (void)viewDidAppear:(BOOL)animated {
  [super viewDidAppear:animated];
  [self.tableView deselectRowAtIndexPath:[self.tableView indexPathForSelectedRow]
                                animated:YES];
}

And of course not in - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath. And the reason is that when you return from the details page you see how the cell is being deselected, which hints you about your previous choice and just looks nice.

• Only necessary classes, no sample code. You could do git submodule add https://github.com/dimzzy/FacebookKit.git to add it to your projects.
• Dynamic selection of JSON parser. It uses NSJSONSerialization on iOS 5 and on older versions it tries to load JSONKit.
• Fixed bug where proper delegate method was not called when user cancels post dialog.

Here it is on GitHub: FacebookKit

id result = nil;
if ([NSJSONSerialization self]) {
    NSError *error = nil;
    result = [NSJSONSerialization JSONObjectWithData:data options:0 error:&error];
    if (error) {
        NSLog(@"%@", error);
    }
} else if ([data respondsToSelector:NSSelectorFromString(@"objectFromJSONData")]) {
    result = [data performSelector:NSSelectorFromString(@"objectFromJSONData")];
} else {
    NSLog(@"JSON parser is not available");
}

This code should be compiled with iOS 5 SDK and it will work on earlier iOS versions. It tries to parse data using the new JSON parser and if it's not available it falls back to JSONKit (or actually any other JSON parser which adds -(id)objectFromJSONData method to NSData). I will continue to include JSONKit in all my projects that need a JSON parser but now there is no direct dependency and when iOS 5 becomes the lowest supported version JSONKit could be just safely removed.

Don't get me wrong though; actually it is an amazing piece of software, it is fast, reliable and works great but it's still one more dependency and third party library to manage. So I'm using this post also to thank the author of JSONKit and wish him all the best!

@interface BALabel : UILabel {
@private
    UIEdgeInsets _textInsets;
    BAVerticalAlignment _verticalAlignment;
}

@property(nonatomic, assign) UIEdgeInsets textInsets;
@property(nonatomic, assign) BAVerticalAlignment verticalAlignment;

- (void)sizeToFitInWidth;
- (void)sizeToFitInWidthMaxHeight:(CGFloat)maxHeight;

@end

Text Insets

It may not be obvious why you could need them but if you'd try to use label as a table section header view you will understand ))). So BALabel has textInsets property which is UIEdgeInsets and it offsets text within label bounds and also is used in label size calculation.

Vertical Alignment

Right now it's possible to align text within the UILabel to the left or to the right or have it centered. Somehow vertical alignment is missing but BALabel allows to stick text to the top, to the bottom or have it centered (which is the default). You probably will need it for multiline labels; if text could span several lines you make text bounds large enough to fit these lines, but if in runtime you have just one short line then it will be centered, which may not look great. You could calculate new height which fits just the available lines but it's much easier to tell label to align text to the top.

sizeToFitInWidth[MaxHeight:]

These are two methods to help you layout labels that are stacked on top of each other where some of them could have several lines of text. Typically you would like them to keep their width and maintain certain spacing. So you call this method(s) for all labels and move them to keep the spacing.

Here is a demo page that shows these features. BALabel is part of the BaseAppKit library.

So I'm running a campaign to cross-promote Deviations in other apps, but why, why on Earth they show my ad within my own app??? Now I did setup text filters and app filters for my app, but this all looks crazy for me...

{
image: "http://img.skitch.com/20100423-jepjp1x576hxfii15ixfxyuacr.png",
title: "Don't panic",
url: "http://www.google.com"
}

But there is an easy fix for this, just add double quotes around names and we have a valid JSON. I wrote the following function that you could call before feeding the string to any parser and so far it seems to be working well for me:

+ (NSString *)fixJSON:(NSString *)s {
  NSRegularExpression *regexp = [NSRegularExpression regularExpressionWithPattern:
                                                     @"[{,]\\s*(\\w+)\\s*:"
                                      options:0
                                        error:NULL];
  NSMutableString *b = [NSMutableString stringWithCapacity:([s length] * 1.1)];
  __block NSUInteger offset = 0;
  [regexp enumerateMatchesInString:s
               options:0
                 range:NSMakeRange(0, [s length])
              usingBlock:^(NSTextCheckingResult *result,
                           NSMatchingFlags flags, BOOL *stop)
   {
     NSRange r = [result rangeAtIndex:1];
     [b appendString:[s substringWithRange:NSMakeRange(offset,
                                       r.location - offset)]];
     [b appendString:@"\""];
     [b appendString:[s substringWithRange:r]];
     [b appendString:@"\""];
     offset = r.location + r.length;
  }];
  [b appendString:[s substringWithRange:NSMakeRange(offset,
                                    [s length] - offset)]];
  return b;
}

If you see any way to improve it or I've missed something please let me know.

The first thing that you start to do when you 'get' the blocks is that you use them everywhere. It not only becomes a part of your code but you want to add them to the existing code to follow your new style. So here is the library of such additions: https://github.com/zwaldowski/BlocksKit

At the moment of this writing the library features:

• Performing blocks on an NSObject.
• Key-value observation (<NSKeyValueObserving>) using a block handler
• Associated objects using an Obj-C API. (Not directly block-related.)
• NSArray, NSSet, and NSDictionary filter utilities
• BKMacros, for more quickly typing out the above.
• NSInvocation creation using blocks
• NSTimer block execution
• UIAlertView, UIActionSheet with block callbacks
• Block initializers for UIControl and UIBarButtonItem
• Initializer for UIGestureRecognizer
• On-touch utilities for UIView.
• both delegation and block callbacks on NSURLConnection

The list of contributors is also quite impressive:

• Michael Ash.
• Jiva DeVoe.
• Igor Evsukov.
• Corey Floyd.
• Landon Fuller, Plausible Labs.
• Mirko Kiefer.
• Robin Lu.
• Jake Marsh.
• Andy Matuschak.
• Aleks Nesterow.
• Kevin O'Neill.
• Jonathan Rentzch.
• Peter Steinberger.
• Jon Sterling.
• Martin Schürrer.
• Zach Waldowski.
• Jonathan Wight.

So even if you are not ready to dive into full-scale blocks usage I would still recommend to have a look at this code for educational purposes.

@property (readonly) double averagePower;
@property (readonly) double peakPower;

If you are curious what to do with these values check out avTouch sample project which contains nice views to show power level.

Metadata was a bit harder task. It turns out that I had Shoutcast stream with icy tags for song title. There is a very detailed article that describes metadata in audio streams and I followed it to upgrade AudioStreamer to extract song info.

The first step is actually to ask for the metadata: you send 'Icy-Metadata:1' in HTTP request and get 'icy-metaint:8192' in HTTP response header. The value is the size of audio blocks between which you get the metadata. Metadata itself is a size byte followed by string that looks like this:

StreamTitle='Artist Name - Song Name';

The second step is to extract the string. I just track its next position and shift audio data over it so the sound is not distorted.

So if you want to see metadata you should call the new constructor [[AudioStreamer alloc] initWithURL:[NSURL URLWithString:kLiveAudioLink] extractMetadata:YES] and subscribe to ASMetadataChangedNotification. Then use metadata property or -(NSDictionary *)parseMetadata call to get parsed strings.

You can find the fork of AudioStreamer code with these features here: https://github.com/dimzzy/AudioStreamer

BAEditableCell.h

#import <UIKit/UIKit.h>

@interface BAEditableCell : UITableViewCell

@property(nonatomic, retain) UITextField *textField;
@property(nonatomic, assign) CGFloat textFieldWidth;

+ (void)stopEditing:(UITableView *)tableView;

@end

BAEditableCell .m

#import "BAEditableCell.h"

#define kTextFieldDefaultWidth 180

@implementation BAEditableCell

@synthesize textField, textFieldWidth;

- (void)dealloc {
    self.textField = nil;
    [super dealloc];
}

- (id)initWithStyle:(UITableViewCellStyle)style
    reuseIdentifier:(NSString *)reuseIdentifier {
    if ((self = [super initWithStyle:style reuseIdentifier:reuseIdentifier])) {
        self.selectionStyle = UITableViewCellSelectionStyleNone;
        self.textField = [[[UITextField alloc] initWithFrame:CGRectZero] autorelease];
        self.textField.autoresizingMask = self.detailTextLabel.autoresizingMask;
        self.textField.font = [UIFont systemFontOfSize:17];
        self.textField.textColor = self.detailTextLabel.textColor;
        [self.contentView addSubview:self.textField];
    }
    return self;
}

- (void)layoutSubviews {
    [super layoutSubviews];
    const CGFloat width = self.contentView.bounds.size.width;
    const CGFloat height = self.contentView.bounds.size.height;
    const CGFloat textWidth = self.textFieldWidth > 0 ?
                      self.textFieldWidth : kTextFieldDefaultWidth;
    const CGFloat textHeight = self.textLabel.bounds.size.height;
    const CGFloat spacing = self.textLabel.frame.origin.x;
    self.textField.frame = CGRectMake(width - spacing - textWidth,
                                      (height - textHeight) / 2,
                                      textWidth, textHeight);
}

+ (void)stopEditing:(UITableView *)tableView {
    for (UITableViewCell *cell in [tableView visibleCells]) {
        if ([cell isKindOfClass:[BAEditableCell class]]) {
            BAEditableCell *editableCell = (BAEditableCell *)cell;
            [editableCell.textField resignFirstResponder];
        }
    }
}

@end

Here I just add text field over the details label, make it match the details label style and layout the cell appropriately. Method +stopEditing: is a convenience to hide the keyboard when user has entered all the data and wants to do something with it.

Here is a better way: in modern Objective C runtime (now it's almost everywhere) associated objects is a feature supported for all proper objects. So I've defined a category for UIView that adds 'cookie' property to all views using this runtime feature:

UIView+BACookie.h

#import <UIKit/UIKit.h>

@interface UIView (UIView_BACookie)

@property(retain) id cookie;

@end

UIView+BACookie.m

#import "UIView+BACookie.h"
#import <objc/runtime.h>

static char BAViewCookieKey;

@implementation UIView (UIView_BACookie)

- cookie {
    return objc_getAssociatedObject(self, &BAViewCookieKey);
}

- (void)setCookie:cookie {
    objc_setAssociatedObject(self, &BAViewCookieKey, cookie, OBJC_ASSOCIATION_RETAIN);
}

@end

Note that the cookie is retained when stored with the view and it will be automatically released when view is deallocated.

So now instead of dancing with 'tag' property or maintaining a custom map we could just stick our object into the view and use it when needed. And you could just copy this code to define your own properties for any other objects that you can't modify.

[[[[UIAlertView alloc] initWithTitle:@"Title"
                             message:@"Message"
                            delegate:nil
                   cancelButtonTitle:@"OK"
                   otherButtonTitles:nil] autorelease] show];

To make things even simpler I define the following macro for the project:

#define BAAlert(TITLE,MSG) [[[[UIAlertView alloc] initWithTitle:(TITLE) \
              message:(MSG) \
             delegate:nil \
    cancelButtonTitle:@"OK" \
    otherButtonTitles:nil] autorelease] show]

Which could be used as simple call:

BAAlert(@"Title", @"Message");

That's it.