Mac Forum / Programming / Mac Programming / April 2008

In article
<14922686-3e10-47ef-9c99-cda6ae2c3bed@a23g2000hsc.googlegroups.com>,

I replied privately off list.

Table of Contents:
  //  AppDelegate.h
  //  AppDelegate.m
  //  AddAction.h
  //  AddAction.m
  //  Item.h
  //  Item.m

//  AppDelegate.h
#import <Cocoa/Cocoa.h>

@class Item;
@class AddAction;

@interface AppDelegate : NSObject {
 NSMutableArray *addActions_;
 NSMutableArray *model_;
}
- (NSMutableArray *)model;
- (void)setModel:(NSMutableArray *)model;
- (IBAction)addItem:(id)sender;
- (void)appendItem:(Item *)item;

- (void)addActionWillClose:(AddAction *)action;
@end

//  AppDelegate.m
#import "AppDelegate.h"
#import "AddAction.h"
#import "Item.h"

@implementation AppDelegate
- (id)init {
 self = [super init];
 if (self) {
   addActions_ = [[NSMutableArray alloc] init];
   model_ = [[NSMutableArray alloc] init];
 }
 return self;
}

// Note: the app's delegate isn't actually ever dealloced. [app
terminate] will
//  just call exit() without cleaning up.
- (void)dealloc {
 [addActions_ makeObjectsPerformSelector:@selector(close)];
 [addActions_ release];
 [model_ release];
 [super dealloc];
}

#pragma mark -
#pragma mark Accessors

- (NSMutableArray *)model {
 return model_;
}

- (void)setModel:(NSMutableArray *)model {
 [model_ autorelease];
 model_ = [model retain];
}

- (void)appendItem:(Item *)item {
// we call setter to trigger bindings. There are many ways to trigger
bindings.
 NSMutableArray *a = [self model];
 [a addObject:item];
 [self setModel:a];
}

#pragma mark -
#pragma mark Actions

- (IBAction)addItem:(id)sender {
 AddAction *action = [[[AddAction alloc] initWithOwner:self]
autorelease];
 [addActions_ addObject:action];
}

- (void)addActionWillClose:(AddAction *)action {
 [addActions_ removeObject:action];
}

#pragma mark -
#pragma mark I/O

- (NSString *)filePath {
 // NSACE stands for NSArrayControllerExample
 NSString *folderPath = [@"~/Library/Application Support/NSACE"
stringByExpandingTildeInPath];
 NSFileManager *fm = [NSFileManager defaultManager];
 BOOL isDir = NO;
 if ( ! ([fm fileExistsAtPath:folderPath isDirectory:&isDir] && isDir))
{
   if( ! [fm createDirectoryAtPath:folderPath attributes:nil]) {
     // if couldn't make dir, fall back on:
     folderPath = [@"~/Documents" stringByExpandingTildeInPath];
   }
 }
 return [folderPath stringByAppendingPathComponent:@"NSACE.nsace"];
}

// for this example, we always write.
-(BOOL)hasModelChanged {
 return YES;
}

- (NSMutableArray *)initialDummyModel {
 NSMutableArray *m = [NSMutableArray array];
 [m addObject:[Item itemWithName:@"John Smith" address:@"Smith Town"
email:@"Smith@example.com"]];
 [m addObject:[Item itemWithName:@"Jim Jones" address:@"Jones Town"
email:@"Jones@example.com"]];
 [m addObject:[Item itemWithName:@"James Kirk" address:@"Kirk City"
email:@"Kirk@example.com"]];
 [m addObject:[Item itemWithName:@"Lena Horn" address:@"Hornville"
email:@"Horn@example.com"]];
 return m;
}

// you can use the command line tool plutil to convert the data file to
a text, XML format
- (BOOL)readFile:(NSString *)filePath error:(NSError **)error {
 NSFileManager *fm = [NSFileManager defaultManager];
 // OK for file not to exist.
 if ( ! [fm fileExistsAtPath:filePath]) {
   // generic initial model.
   [self setModel:[self initialDummyModel]];
   return YES;
 }
 NSData *data = [NSData dataWithContentsOfFile:filePath options:0
error:error];
 if (data) {
   NSMutableArray *m = [NSKeyedUnarchiver unarchiveObjectWithData:data];
   if (m) {
     [self setModel:m];
     return YES;
   }
   NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:
     NSLocalizedString(@"CouldntDecode", @""),
NSLocalizedDescriptionKey,
     nil];
   *error = [NSError errorWithDomain:@"appDomain" code:-2
userInfo:dict];
 }
 return NO;
}

- (BOOL)writeFile:(NSString *)filePath error:(NSError **)error {
 NSData *data = [NSKeyedArchiver archivedDataWithRootObject:model_];
 if (nil == data) {
   NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:
     NSLocalizedString(@"CouldntMakeEncode", @""),
NSLocalizedDescriptionKey,
     nil];
   *error = [NSError errorWithDomain:@"appDomain" code:-1
userInfo:dict];
   return NO;
 }
 return [data writeToFile:filePath options:NSAtomicWrite error:error];
}

// Called 'cause we are delegate of main window
#pragma mark -
#pragma mark App Callbacks (this is the app delegate)

- (void)windowWillClose:(NSNotification *)notification {
 [NSApp terminate:nil];
}

- (BOOL)applicationShouldTerminateAfterLastWindowClosed:(NSApplication
*)sender {
 return YES;
}

- (void)applicationDidFinishLaunching:(NSNotification *)notification {
 NSError *error = nil;
 if( ! [self readFile:[self filePath] error:&error] ){
   [NSApp presentError:error];
 }
}

- (NSApplicationTerminateReply)applicationShouldTerminate:(NSApplication
*)sender {
 if ([self hasModelChanged]) {
   NSError *error = nil;
   if( ! [self writeFile:[self filePath] error:&error] ){
     [NSApp presentError:error];
   }
 }
 return NSTerminateNow;
}

@end

//  AddAction.h

#import <Cocoa/Cocoa.h>

@class Item;
@class AppDelegate;

@interface AddAction : NSObject {
 Item *item_;
 AppDelegate *owner_; // WEAK
 IBOutlet NSWindow *window_;
}
- (id)initWithOwner:(AppDelegate *)owner;
- (Item *)item;
- (void)setItem:(Item *)item;
- (NSWindow *)window;
- (IBAction)cancel:(id)sender;
- (IBAction)ok:(id)sender;

- (void)close;

@end

//  AddAction.m

#import "AddAction.h"
#import "AppDelegate.h"
#import "Item.h"

// Feel free to comment out the lines labelled:
//alloc/dealloc testing
// once you are convinced we aren't leaking addActions.

@implementation AddAction
- (id)initWithOwner:(AppDelegate *)owner {
NSLog(@"AddAction initWithOwner"); //alloc/dealloc testing
 self = [super init];
 if (self) {
   owner_ = owner;
   NSNib *itemNib = [[[NSNib alloc] initWithNibNamed:@"itemEdit"
bundle:nil] autorelease];
   [itemNib instantiateNibWithOwner:self topLevelObjects:nil];
   item_ = [[Item alloc] init];
   [window_ makeKeyAndOrderFront:nil];
 }
 return self;
}

- (void)dealloc {
NSLog(@"AddAction dealloc"); //alloc/dealloc testing
 [item_ release];
 owner_ = nil;
 [super dealloc];
}

- (Item *)item {
 return item_;
}

- (void)setItem:(Item *)item {
 [item_ autorelease];
 item_ = [item retain];
}

- (NSWindow *)window {
 return window_;
}

- (void)close {
 [owner_ addActionWillClose:self];
 [window_ orderOut:nil];
// Sketch has a comment about Cocoa bindings creating a retain loop in
Tiger.
// this line fixes that.
 [self unbind:@"item"];
}

- (IBAction)cancel:(id)sender {
 [self close];
}

- (IBAction)ok:(id)sender {
// so we don't need to tab out of last feed for it to be seen.
 [window_ endEditingFor:nil];

 [owner_ appendItem:[self item]];
 [self close];
}

@end

//  Item.h
@interface Item : NSObject<NSCoding> {
@private
 NSString *name_;
 NSString *email_;
 NSString *address_;
 NSColor *color_;
}
+(Item *)itemWithName:(NSString *)name
     address:(NSString *)address
       email:(NSString *)email ;

- (NSString *)name;
- (void)setName:(NSString *)name;

- (NSString *)email;
- (void)setEmail:(NSString *)email;

- (NSString *)address;
- (void)setAddress:(NSString *)address;

- (NSColor *)color;
- (void)setColor:(NSColor *)color;

@end

//  Item.m
#import "Item.h"

@implementation Item

+(Item *)itemWithName:(NSString *)name address:(NSString *)address
email:(NSString *)email {
 Item *val = [[[Item alloc] init] autorelease];
 [val setName:name];
 [val setAddress:address];
 [val setEmail:email];
 [val setColor:[NSColor blackColor]];
 return val;
}

- (id)init{
 self = [super init];
 return self;
}

- (void)dealloc {
 [name_ release];
 [email_ release];
 [address_ release];
 [color_ release];
 [super dealloc];
}

- (NSString *)name {
 return name_;
}

- (void)setName:(NSString *)name {
 [name_ autorelease];
 name_ = [name copy];
}

- (NSString *)email {
 return email_;
}

- (void)setEmail:(NSString *)email {
 [email_ autorelease];
 email_ = [email copy];
}

- (NSString *)address {
 return address_;
}

- (void)setAddress:(NSString *)address {
 [address_ autorelease];
 address_ = [address copy];
}

- (NSColor *)color {
 return color_;
}

- (void)setColor:(NSColor *)color {
 [color_ autorelease];
 color_ = [color retain];
}

- (void)encodeWithCoder:(NSCoder *)aCoder {
 if(name_){ [aCoder encodeObject:name_ forKey:@"name"]; }
 if(email_){ [aCoder encodeObject:email_ forKey:@"email"]; }
 if(address_){ [aCoder encodeObject:address_ forKey:@"address"]; }
 if(color_){ [aCoder encodeObject:color_ forKey:@"color"]; }
}

- (id)initWithCoder:(NSCoder *)aDecoder {
 name_ = [[aDecoder decodeObjectForKey:@"name"] retain];
 email_ = [[aDecoder decodeObjectForKey:@"email"] retain];
 address_ = [[aDecoder decodeObjectForKey:@"address"] retain];
 color_ = [[aDecoder decodeObjectForKey:@"color"] retain];
 return self;
}

@end