// do something here

Apparently, there is no way to take a UIButton and set it’s property to “selected” for the purposes of having the UI display the button with the background image as it appears in the UIControlStateSelected state. As a result, I decided that I would just track which of my series of UIButton controls was supposed to be selected, set the background image of all the buttons to nil, and set the UIControlStateNormal background image of the button to an image, and it seemed to work OK.

The code to do this, however, was kind of ugly, and my co-worker on this project pushed me to find a better way. The result is the ExpandoButton class that we created and added to the project. For this class (which of course inherits UIButton), I wanted to be able to initialize it to a particular background image, and I wanted to have a message I could send the button to have it switch back and forth from the unselected background image to the selected background image.

Here are the header and implementation files for the ExpandoButton object class:

//
//  ExpandoButton.h
//
 
#import <Foundation/Foundation.h>
 
@interface ExpandoButton : UIButton {
 
}
 
- (void)setSelectedImage:(BOOL)isSelected;
 
@end

//
//  ExpandoButton.m
//
 
#import "ExpandoButton.h"
 
@implementation ExpandoButton
 
- (id)initWithCoder:(NSCoder *)decoder
{
	if (self = [super initWithCoder:decoder]) {
		UIImage *image = [UIImage imageNamed:@"button_normal.png"];
		UIImage *stretchImage =
					[image stretchableImageWithLeftCapWidth:4.0 topCapHeight:4.0];
		[self setBackgroundImage:stretchImage forState:UIControlStateNormal];
		self.backgroundColor = [UIColor clearColor];
	}
 
	return self;
}
 
- (void)setSelectedImage:(BOOL)isSelected
{
	NSString *file;
 
	if (isSelected)
	{
		file = @"button_selected.png";
	}
	else 
	{
		file = @"button_normal.png";
	}
 
	UIImage *image = [UIImage imageNamed:file];
	UIImage *stretchImage =
				[image stretchableImageWithLeftCapWidth:4.0 topCapHeight:4.0];
	[self setBackgroundImage:stretchImage forState:UIControlStateNormal];
}
 
@end

A few notes here about the implementation file. You will of course need to add the stretchable unselected and selected button images to your project and change the names above, along with changing the cap width and height to your needs. Also, the initWithCoder part took us a few moments to figure out, it wasn’t working at first because we weren’t calling the super’s initWithCoder, just the regular old init. And finally, keep in mind that there is no error checking, optimization, or memory leak checking going on here.

To actually use the ExpandoButton, go into your Interface Builder, and from the Library window, select the Classes option, make sure the choice list right below is set to Library, and you should then be able to scroll the list and see an ExpandoButton, which looks just like a UIButton. Put that object on your view and set the size and title if you wish. VERY IMPORTANT: Make sure to set the button type of your ExpandoButton to Custom instead of the default of Rounded Rect.

Then, in your view controller header file, set up an IBOutlet with type of ExpandoButton (don’t forget the header or @class), along with the corresponding @property, and in the view controller implementation file, set up the @synthesize. After you save the files and build, go back into Interface Builder and set up the connection between the IBOutlet and the ExpandoButton on the view. (I hope you remembered where it was. When you set it to Custom and if you do not have any title text, the button sort of disappears.)

If everything is hooked up and working correctly, in your implementation file code, you can do something like this:

[myExpandoButton setSelectedImage:YES];

And the button should show up with the selected background image.

Justin Munger gave a presentation on some of the new features of the iPad and how to utilize them in the iPhone SDK at the Columbus iPhone Developer User Group on May 25, 2010. The topics he covered were the new modal dialogs, split views, gesture recognizers, and building a universal application for both iPhone and iPad.

His sample code and presentation slides are located on the CIDUG web site at:

http://groups.google.com/group/cidug/files

If you are using Xcode for either Macintosh or iPhone development, please go to one of your implementation files in Xcode right now, hold down Option and Command and press the up arrow. Your life will be much better.

Most applications need data, shockingly enough. I started working on my iPhone application in earnest a couple of years ago, before the availability of CoreData on the iPhone OS. The project is just now picking up some momentum, but I was pretty sure that I wanted to stay with SQLite on the device.

As it turns out, even though using SQLite with Objective-C is not too terribly complicated, I thought that there could have been a better way, and so I found Gus Mueller’s FMDB for iPhone page. He wrote an Objective-C wrapper around the SQLite calls that seems to work very well.

In order to use FMDB, you will still need to follow along with steps in other SQLite tutorials (such as this one) and do things like setting up your database file in Firefox SQLite Manager, copying the database file from the resources to the local file system on the device if needed in applicationDidFinishLaunching, and opening the database using the FMDB open method.

Once you have your database open, you can do nice things such as this:

	FMResultSet *rs = [db executeQuery:@"select * from companies where state = ?",
					   stateToSearchFor, nil];
	while ([rs next])
	{
		NSLog(@"Name: %@", [rs stringForColumn:@"companyname"];
	}

Just make sure that, if you want to hold your database open throughout the life cycle of your application (instead of opening and closing the database each time you read, write, or delete a record), make sure to use retain on the object returned by the FMDB open command, as the code returns an autorelease object. Or you could of course just modify the FMDB code.

I was looking to be able see the data in one of my SQLite3 database tables on the iPhone in the console, but could not find a nice and easy way to do this. Here is my solution to the problem.

This routine is set up to take in an NSMutableArray corresponding to the rows of the tabular data, and each of the elements of the array is an NSMutableArray of the columnar data. All of the items in the column array need to be of type NSString, and the first element of the rows array should be a row of column headers. If you need other types or do not want to use a headers row, please feel free to modify the code as you see fit.

Here is the NSLogTable header and implementation files that I put together for this purpose:

//
//  NSLogTable.h
//
 
#import <Foundation/Foundation.h>
 
@interface NSLogTable : NSObject {
 
}
 
+ (void)dumpTable:(NSMutableArray *)rows;
 
@end

//
//  NSLogTable.m
//
 
#import "NSLogTable.h"
 
@implementation NSLogTable
 
+ (void)dumpTable:(NSMutableArray *)rows
{
	int idx = 0;
	NSMutableArray *rowData;
	int colWidths[100];
	NSString *s;
	NSMutableString *ms = [[NSMutableString alloc] init];
	BOOL firstRow = YES;
 
	for (int i = 0; i < 100; i++) colWidths[i] = 0;
 
	// get the maximum column widths
	for (id row in rows)
	{
		rowData = (NSMutableArray *)row;
		for (int i = 0; i < [rowData count]; i++)
		{
			s = [rowData objectAtIndex:i];
			if ([s length] > colWidths[i])
			{
				colWidths[i] = [s length];
			}
		}
	}
 
	for (id row in rows)
	{
		[ms setString:@""];
		if (firstRow)
		{
			[ms appendString:@"     "];
			firstRow = NO;
		} else {
			[ms appendFormat:@"%4d ", idx];
		}		
 
		rowData = (NSMutableArray *)row;
		for (int i = 0; i < [rowData count]; i++)
		{
			s = [rowData objectAtIndex:i];
			[ms appendString:[s stringByPaddingToLength:colWidths[i] withString:@" " startingAtIndex:0]];
			[ms appendString:@" "];
		}
 
		NSLog(@"%@", ms);
		idx++;
	}
}
 
@end

Once you build your rows array (make sure to import the NSLogTable.h file into your implementation file), you send it to the console like this, where theData is your NSMutableArray:

[NSLogTable dumpTable:theData];

As always, please keep in mind that there is minimal optimization and error checking going on in this code. If you have any suggestions, please let me know.

The biggest problem that I have had over the past 2 years or so of working with the iPhone SDK is the seemingly insurmountable learning curve to have you applications do something reasonably simple. I think this is partly due to my lack of any free time to dive into the whole iPhone SDK/Cocoa Touch/Objective-C world, and partly due to my straight ahead, VB6 development mentality.

For example, in my VB6 applications, if I need to display a dialog to the user to collect some bit of information, the parent code creates the form and shows it, and the child code closes down the child form when the user is done. This reasonably simple task has proven a bit elusive, as it seems like at times, I can’t get this to work for one reason or another.

Alas, I think I have finally figured out a good way to do this very task. Now, all I do in my parent view controller is to run the following code when I need to:

ChildViewController *controller = [[ChildViewController alloc]
					initWithNibName:@"ChildViewController" bundle:nil];
[self presentModalViewController:controller animated:YES];
[controller release];

In the new view that comes up by calling the code above, I use this code to get rid of the new view:

[[self parentViewController] dismissModalViewControllerAnimated:YES];

(Now of course, there is more going on here, as you need a way to pass values back and forth from one view to another. I think I might have a blog post from a few months ago to talk about this process.)

The end result is that I now have a simple way to show and dismiss forms in much the same way that I did with VB6. Does discovering this mean that I will continue to bumble around in the dark when it comes to the mysteries of inheriting from the correct classes in the iPhone SDK? Probably. Am I worried about it? Nope.

Oh, and I hope everyone has a nice Christmas (or insert your own holiday here, Kwanzaa, Festivus, Hanukkah, etc.), and drive safely out there. Grandma still hasn’t recovered after being run over by a reindeer.

The Central Ohio .NET Developers Group held their final meeting of the year last night at the Microsoft office in Polaris. Four people gave short demos of Xbox, Zune HD, Windows Mobile, and iPhone, and talked about developing for each platform.

The highlight of the evening was my name being drawn as winning the year’s final and perhaps most craptastic door prize, which I then gave to my coworker who was attending the meeting with me. He is into free t-shirts.

Lecture 18 from the Stanford University iPhone Application Programming class was the class wrap-up lecture hosted by Evan Doll. He covered unit testing and localization on the iPhone platform, as well as answering some common iPhone SDK questions. The information he presented is somewhat relevant, especially with regards to the localization information, as the iPhone app store is becoming available in more countries.

Thanks to Evan and Alan and the crew, the videos were in general very informative and pertinent.

Oh, and Happy Halloween everyone!

Geoffrey Goetz gave a presentation on iPhone software development at the Columbus iPhone Developer User Group on October 27, 2009. He mostly talked about a lot of different topics, most importantly the creation of an iPhone application that utilized different types of view controllers.

During his demo, he created a new project from scratch based on the window template of the iPhone SDK, even though he was creating an application with a tab bar. I am probably going to revisit one of the applications that I am working on, which is also an application that uses a tab bar. However, I have had some issues with it, and I think that after seeing Geoffrey’s demo, it might be better to create it the way he did it than to use the tab bar application template included in the SDK.

Geoffrey posted his demo code and presentation files to the CIDUG web site.  Here is a link:

http://groups.google.com/group/cidug/files

Thanks to Geoffrey, he did a nice job (even though he ran way way over the time) and his information was super relevant.

I am working on an iPhone application with some regular views and a table view, and I need to have the table view communicate with the main view. Seemingly a simple enough problem, but as I searched and searched, I could not find any concrete examples of how to do this, just a bunch of vague references about how views need to talk to each other and a larger number of folks suggesting the use of singletons.

Now, I have been known to use a global variable or two in my day, but in this instance, I figured I would dig a bit deeper.

As it turns out, the means to accomplish this for my task was easier than I thought. All that I did was to store a reference to the primary view controller in my secondary view controller, and that gave me access to any of the member variables in that class. In addition, this also gives me the ability to send messages to methods in that class.

So, in my primary view controller header file, we have the following:

#import <UIKit/UIKit.h>
 
@interface PassingValuesBetweenViewsViewController : UIViewController {
	IBOutlet UILabel *label;
	int selectedValue;
}
 
@property (nonatomic, retain) UILabel *label;
@property (nonatomic) int selectedValue;
 
- (IBAction)buttonWasTapped;
 
- (void)tableItemWasSelected:(int)itemSelected;
 
@end

And in the primary view controller implementation file:

#import "PassingValuesBetweenViewsViewController.h"
#import "SecondaryViewController.h"
 
@implementation PassingValuesBetweenViewsViewController
 
@synthesize label;
@synthesize selectedValue;
 
- (void)didReceiveMemoryWarning {
	// Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
 
	// Release any cached data, images, etc that aren't in use.
}
 
- (void)viewDidUnload {
	// Release any retained subviews of the main view.
	// e.g. self.myOutlet = nil;
}
 
- (void)dealloc {
    [super dealloc];
}
 
- (IBAction)buttonWasTapped
{
	SecondaryViewController *svc = [SecondaryViewController alloc];
	svc.vc = self;
	[self.view addSubview:svc.view];
}
 
- (void)tableItemWasSelected:(int)itemSelected
{
	NSLog(@"tableItemWasSelected called with %d", itemSelected);
	NSLog(@"The current value of selectedValue is %d", selectedValue);
	label.text = [NSString stringWithFormat: @"You selected #%d", itemSelected];
}
 
@end

The selectedValue member is an integer that gets updated in the table view with the selected cell, and the tableItemWasSelected methods is called from the table view when a cell is selected. In the buttonWasTapped method, the secondary view controller gets a reference to the primary view controller after it is allocated, and this enables the magic to happen.

Here is the secondary view controller header file:

#import <UIKit/UIKit.h>
 
#import "PassingValuesBetweenViewsViewController.h"
 
@interface SecondaryViewController : UITableViewController {
	PassingValuesBetweenViewsViewController *vc;
}
 
@property (nonatomic, retain) PassingValuesBetweenViewsViewController *vc;
 
@end

And the secondary view controller implementation file:

#import "SecondaryViewController.h"
 
@implementation SecondaryViewController
 
@synthesize vc;
 
- (void)didReceiveMemoryWarning {
	// Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];
 
	// Release any cached data, images, etc that aren't in use.
}
 
- (void)viewDidUnload {
	// Release any retained subviews of the main view.
	// e.g. self.myOutlet = nil;
}
 
#pragma mark Table view methods
 
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 1;
}
 
// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return 50;
}
 
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
 
    static NSString *CellIdentifier = @"Cell";
 
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }
 
    // Set up the cell...
	cell.textLabel.text = [NSString stringWithFormat: @"Cell #%d", indexPath.row];
    return cell;
}
 
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
	vc.selectedValue = indexPath.row;
	[vc tableItemWasSelected:indexPath.row];
	[self.view removeFromSuperview];
}
 
- (void)dealloc {
    [super dealloc];
}
 
@end

As you can see here, the primary view controller is references from the didSelectRowAtIndexPath method, both in setting a member variable through standard dot notation, and in sending a message with a parameter to the primary view controller.

I have posted a copy of this code if you would like to download the entire project and work with it:

PassingValuesBetweenViews.zip

Please keep in mind this is not finished or production quality code.