main.m

/*
 Erica Sadun, http://ericasadun.com
 iPhone Developer's Cookbook, 3.0 Edition
 BSD License, Use at your own risk
 */

#import <UIKit/UIKit.h>
#import <MediaPlayer/MediaPlayer.h>
#import "MPMediaItem-Properties.h"

#define COOKBOOK_PURPLE_COLOR	[UIColor colorWithRed:0.20392f green:0.19607f blue:0.61176f alpha:1.0f]
#define BARBUTTON(TITLE, SELECTOR) 	[[[UIBarButtonItem alloc] initWithTitle:TITLE style:UIBarButtonItemStylePlain target:self action:SELECTOR] autorelease]

@interface TestBedViewController : UIViewController
{
	NSMutableString *log;
	IBOutlet UITextView *textView;
}
@property (retain) NSMutableString *log;
@end

@implementation TestBedViewController
@synthesize log;

- (void) doLog: (NSString *) formatstring, ...
{
	va_list arglist;
	if (!formatstring) return;
	va_start(arglist, formatstring);
	NSString *outstring = [[[NSString alloc] initWithFormat:formatstring arguments:arglist] autorelease];
	va_end(arglist);
	[self.log appendString:outstring];
	[self.log appendString:@"\n"];
	textView.text = self.log;
}

- (void) action: (UIBarButtonItem *) bbi
{
	self.log = [NSMutableString string];
	MPMediaQuery *query = [MPMediaQuery songsQuery];
	MPMediaPropertyPredicate *mpp = [MPMediaPropertyPredicate 
									 predicateWithValue:@"road" 
									 forProperty:MPMediaItemPropertyTitle     
									 comparisonType:MPMediaPredicateComparisonContains];
	[query addFilterPredicate:mpp];
	
	NSArray *collections = query.collections;
	[self doLog:@"You have %d matching tracks in your library\n", collections.count];
	
	for (MPMediaItemCollection *collection in collections)
	{
		for (MPMediaItem *item in [collection items])
            [self doLog:@"%@, %@", item.title, item.artist];
		
		NSPredicate *pred = [NSPredicate predicateWithFormat:@"artist contains[cd] %@", @"Joel"];
		NSArray *array = [[collection items] filteredArrayUsingPredicate:pred];
		for (MPMediaItem *item in array)
			[self doLog:@"Filtered: %@ %@", item.title, item.artist];
	}
}

- (void) viewDidLoad
{
	self.navigationController.navigationBar.tintColor = COOKBOOK_PURPLE_COLOR;
	self.navigationItem.rightBarButtonItem = BARBUTTON(@"Action", @selector(action:));
}
@end

@interface TestBedAppDelegate : NSObject <UIApplicationDelegate>
@end

@implementation TestBedAppDelegate
- (void)applicationDidFinishLaunching:(UIApplication *)application {	
	UIWindow *window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
	UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:[[TestBedViewController alloc] init]];
	[window addSubview:nav.view];
	[window makeKeyAndVisible];
}
@end

int main(int argc, char *argv[])
{
	NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
	int retVal = UIApplicationMain(argc, argv, nil, @"TestBedAppDelegate");
	[pool release];
	return retVal;
}