NSMutableArray 排序

2009年12月25日 05:17

原文来自:http://iphone.ipsw.info/2009/10/nsmutablearray.html

 - (NSArray *)sortedArrayUsingSelector:(SEL)comparator

Parameters
comparator

A selector that identifies the method to use to compare two elements at a time. The method should returnNSOrderedAscending if the receiver is smaller than the argument, NSOrderedDescending if the receiver is larger than the argument, and NSOrderedSame if they are equal

 

NSArray *sortedArray =
    [anArray sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];

 

 


@property (nonatomicreadwriteretain) NSMutableArray *parameters;

 

[self.parameters sortUsingSelector:@selector(compare:)];


 

 

#pragma mark -

 

- (NSComparisonResult)compare:(id)inObject {

     NSComparisonResult result = [self.name compare:[(MPURLRequestParameter *)inObject name]];

     if (result == NSOrderedSame) {

result = [self.value compare:[(MPURLRequestParameter *)inObject value]];

     }

 

      return result;

}

 

//////////////////////////////////////////////////////////

 

sortedArrayUsingFunction:适合基本类型(支持compare方法)

#pragma mark SORT METHOTDS

NSInteger sortObjectsByLatestTime(id obj1, id obj2, void *context)

{

 

NSDate* d1 = [(MessageGroup*)obj1 latestTime];

NSDate* d2 = [(MessageGroup*)obj2 latestTime];

//sort by desc

return [d2 compare:d1];

}

 

NSInteger dateSort(id obj1, id obj2, void *context)

{

NSDate* d1 = ((Inbox*)obj1).datetime;

NSDate* d2 = ((Inbox*)obj2).datetime;

return [d1 compare:d2];

}

////////////////////////////////////////////////////////////////////

 

 

-(NSArray*)sortedMessages

{

return [[groupMessages allValuessortedArrayUsingFunction:sortObjectsByLatestTimecontext:NULL];

}

//////////////////////////////////////////////////////////

sortUsingDescriptors:适合元素是dict类型,initWithKey既是dict key.

 

NSMutableArray *regions = [NSMutableArray array];

 

 

NSSortDescriptor *sortDescriptor = [[NSSortDescriptor allocinitWithKey:@"name" ascending:YES];

NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor];

[regions sortUsingDescriptors:sortDescriptors];

[sortDescriptor release];


The Original paper come from: http://www.webdesignerdepot.com/2009/11/the-ultimate-toolbox-for-iphone-development/

 

 

iPhone development can be intimidating, especially to someone who’s unfamiliar with Macs, or the way iPhone apps work.

But with currently more than 100,000 apps officially available from the App Store, it’s kind of hard for a developer to ignore the potential market the iPhone provides.

And there are apps for virtually anything you could think of, from games to productivity apps to horoscopes to news and more.

Below are 70 tools, tutorials, and resources to help you get started developing your own iPhone apps. There’s everything from basic tutorials to templates to resource libraries to help you on your way.

 

Tutorials

How to Get Started with iPhone Dev A very thorough article on how to start developing your own iPhone apps.

Learn How to Develop for the iPhone
An excellent tutorial from Tuts+ that covers the development of websites specifically for the iPhone or iPod Touch.

First iPhone Application
This post from iPhone SDK offers an extensive overview of how to develop your first basic iPhone application.

How I Wrote an iPhone Application
This article gives a first-hand account of building an iPhone app, including the thought process behind development and some code snippets.

Cocoa Touch Tutorial: iPhone Application Example
This tutorial covers how to develop Cocoa iPhone apps using Interface Builder to quickly build your first application.

Sliding UITextFields Around to Avoid the Keyboard
This tutorial covers the basics of moving text fields around on an iPhone app so that they don’t interfere with the on-screen keyboard.

Develop iPhone Web Applications with Eclipse
A very comprehensive article from IBM on using Eclipse to develop your iPhone apps.

iPhone Development with PHP and XML
Another article from IBM on developing apps, this time with PHP and XML.

Developing iPhone Applications Using Ruby on Rails and Eclipse
The first in a series of articles from IBM on using Ruby on Rails and Eclipse to develop iPhone apps.

Your First iPhone Application
A tutorial for creating your first app, from the official Apple iPhone OS Reference Library.

How to Make an iPhone Application on XCode
A simple video tutorial that shows you how to build an iPhone app on XCode.

iPhone SDK Development Tutorial – First Step Towards the App Store
Another great video tutorial that shows the first steps in building apps for the app store using XCode.

Make an iPhone App Using the Envato API
A great tutorial from Tuts+ that shows you how to use the Envato Marketplace API to develop your own iPhone apps.

Building PhotoKast: Creating an iPhone App in One Month
This photo tutorial shows you the complete process of building an iPhone app, with illustrations.

Perfect Multi-Column CSS Liquid Layouts: iPhone Compatible
This tutorial shows you how to build liquid CSS layouts that are iPhone compatible.

iPhone Dev Sessions: How to Make an Orientation-Aware Clock
This tutorial covers how to build an orientation-aware clock, which provides great insight into building any app that is orientation-aware.

iPhone SDK: Interface Builder Tutorial
A very short, simple intro to how the Interface Builder works.

Parsing XML Files
This tutorial from iPhone SDK offers all the information you need for parsing XML files within applications on the iPhone.

iPhone Gaming Framework: Stage 1 Tutorial
This tutorial shows you how to get your basic screen management system running so you can start developing iPhone games.

iPhone Game Programming Tutorial: Part 1
Here’s a complete tutorial for creating a Pong-like iPhone game.

So You’re Going to Write an iPhone App…
This tutorial gives a great overview of the app development process and some things to consider while developing.

Advanced iPhone Development
This article looks at some more advanced aspects of iPhone application development.

Building an iPhone App in a Day
A brief look at what it takes to build an iPhone app really quickly.

Build an iPhone Webapp in Minutes with Ruby, Sinatra and iUI
An overview of fast development techniques for iPhone webapps.

Finding iPhone Memory Leaks: A “Leaks” Tool Tutorial
Learn how to find memory leaks in your iPhone apps using the “Leaks” tool.

iPhone Application Development, Step by Step
A great, step-by-step look at the app development process.

iPhone App Development: Where to Start
A great article that talks about iPhone app development from the perspective of someone who’s never done any Apple or Mac development (or even used a Mac) previously.

Parsing XML on the iPhone
Another great look at how to parse XML within iPhone apps.

iPhone Development Central
This site offers a huge variety of video tutorials for iPhone developers, broken down for beginner, intermediate and advanced developers.

iPhone SDK Tutorial: Reading Data from a SQLite Database
A simple tutorial for using SQLite with the iPhone SDK.

iPhone Dev Sessions: Create a Navigation-Based Application
This comprehensive tutorial shows you how to create a navigation-based application from XCode.

iPhone SDK Tutorial: Build a Simple RSS Reader for the iPhone
This tutorial shows you how to build a simple RSS feed reader from the ground up.

Multi Touch Tutorial
This tutorial gives a great introduction to the iPhone’s multi touch interface.

Howto: iPhone Application Development Environment
This tutorial shows how one developer set up their app development environment, with tips for setting up your own.

iPhone Application Programming
Downloadable lectures from Stanford’s iPhone Application Programming class.

Introduction to iPhone Application Development
Downloadable course materials from a one-week MIT course on iPhone app development.

iPhone Programming Tutorial – Using openURL to Send Email from Your App
This tutorial shows you how to use openURL to allow your apps to send email.

How to Create Your first iPhone Appllication
Another comprehensive tutorial for creating your first iPhone app from the ground up.

 

Tools

PhoneGap
PhoneGap speeds up app development for developers who already know HTML and JavaScript but also want to take advantage of the core features of the iPhone SDK.

Morfik
Morfik is a downloadable tool that speeds up development of rich internet apps.

iPhone GUI PSD 3.0
A set of downloadable Photoshop files with iPhone GUI images.

iPhone PSD Vector Kit
A PSD set that comes with several button elements as well as six different iPhone interface options.

iPhone Wire Frames
iPhone Wire Frame stencil files for use with OmniGraffle.

Yahoo! Design Stencil Kit
A downloadable package of UI stencils from Yahoo! that includes iPhone images.

iPhone UI Vector Elements
Downloadable vector images of different iPhone elements.

Three20
A library of open source iPhone app elements and frameworks.

gdata-objectivec-client
The Google Data API’s Objective-C client library.

Are You iPhoned?
A simple site that checks to see if you’re visiting from an iPhone and gives you the code to do the same on your own sites.

31 iPhone Applications with Source Code
A library of more than thirty iPhone apps with their source code available.

iPhone Samples
Sample UI elements for the iPhone.

iUI: iPhone User Interface Framework
A free UI framework for Safari development on the iPhone.

35 Free Icon Sets for your iPhone
35 icon sets you can download and use in your iPhone development.

TestiPhone.com – iPhone Simulator
An iPhone simulator for testing your iPhone web apps.

iPhoney
Another simulator for testing your iPhone web apps.

 

Resources and Articles

iPhone Dev Connection
Apple’s official iPhone development site.

The Darker Side of iPhone App Development
An article that covers some of the restrictions and limitations imposed by Apple for iPhone apps.

Avoiding iPhone App Rejection From Apple
A great article that tells you how to not get rejected by the App Store.

14 Essential XCode Tips, Tricks and Resources for iPhone Devs
A roundup of some great developer resources.

iPhoneDevForums
An iPhone/iPod touch development discussion forum aimed to assist fellow developers as they code in Apple’s SDK. There is also a job board where developers and entrepreneurs can share and discover one another’s services to start projects of their own.

iCodeBlog
The iCodeBlog has tons of great articles, news, and tutorials related to iPhone development.

iPhoneWebDev
An iPhone developer resource center and community.

iPhone Toolbox
A blog that covers news, apps, and more related to the iPhone.

iPhone Open Application Development
O’Reilly Media’s iPhone application development book.

iPhone Web Application Submission
The official place to submit your iPhone web applications.

iPhone Application and Website Development: All Tools and Tutorials You Need
A huge roundup of resources for developing both iPhone apps and optimized websites.

iPhone Dev SDK Forum
A great forum for getting answers to your iPhone SDK development questions.

iPhone Application Developer Interview
An interview with iPhone app developer Darren Andes, the developer of the Baby Tracker: Nursing app.

Seven Things all iPhone Apps Need
An overview of some must-have features for iPhone apps.

5 Free Resources for iPhone App Development
A roundup of some handy, free resources for developing your iPhone apps.

Top 10 Tutorials to Develop iPhone Apps
A ranked listing of great iPhone development tutorials.

100 Free Courses and Tutorials for Aspiring iPhone App Developers
A huge list of iPhone development courses, many from traditional universities.

29 iPhone App & Website Development Resources and Tutorials Places
Another excellent roundup of iPhone development resources.

 

 

Drawing a Grid in a UITableView

2009年12月22日 22:20

The Original paper come from: http://dewpoint.snagdata.com/2008/10/31/drawing-a-grid-in-a-uitableview/

 UITableView is probably the most used view on the iPhone. It’s flexible and the UI is ideally suited to use on the iPhone. There are lots of examples on how to add multiple items to a UITableViewCell. However, I needed to present some data in a more traditional spreadsheet style grid. The results worked well and enabled me to pack a lot of information on the screen that was very hard to follow without the vertical grid. I’ll show a very simplified version here you can use to add vertical lines to your UITableView.

 First we need to create a subclass of UITableViewCell. This is so we can override drawrect and draw our lines and to add an array to hold a list of positions where we’ll draw the lines.

@interface MyTableCell : UITableViewCell {
	NSMutableArray *columns;
}
- (void)addColumn:(CGFloat)position;
@end

 In this simplified example we’ll leave the positioning of the actual text in the cells in the UITableViewController and place it manually (full source code is attached at the end). We’re just providing a mechanism for drawing vertical lines to make a grid. Column locations are added by calling addColumn:

- (void)addColumn:(CGFloat)position {
	[columns addObject:[NSNumber numberWithFloat:position]];
}

 Now lets override drawRect. In it we grab the current graphics context and set the line color and width. Then we iterate over our columns array drawing a line from the top of the cell row to the bottom at each position stored in the array.

- (void)drawRect:(CGRect)rect {
	CGContextRef ctx = UIGraphicsGetCurrentContext();
	// Use the same color and width as the default cell separator for now
	CGContextSetRGBStrokeColor(ctx, 0.5, 0.5, 0.5, 1.0);
	CGContextSetLineWidth(ctx, 0.25);
 
	for (int i = 0; i < [columns count]; i++) {
		CGFloat f = [((NSNumber*) [columns objectAtIndex:i]) floatValue];
		CGContextMoveToPoint(ctx, f, 0);
		CGContextAddLineToPoint(ctx, f, self.bounds.size.height);
	}
 
	CGContextStrokePath(ctx);
 
	[super drawRect:rect];
}

 To add columns to the view just call

[cell addColumn:50];

 when you’re building each cell.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
 
	NSString *MyIdentifier = [NSString stringWithFormat:@"MyIdentifier %i", indexPath.row];
 
	MyTableCell *cell = (MyTableCell *)[tableView dequeueReusableCellWithIdentifier:MyIdentifier];
 
	if (cell == nil) {
		cell = [[[MyTableCell alloc] initWithFrame:CGRectZero reuseIdentifier:MyIdentifier] autorelease];
 
		UILabel *label = [[[UILabel alloc] initWithFrame:CGRectMake(0.0, 0, 30.0,tableView.rowHeight)] autorelease];
		[cell addColumn:50];
		label.tag = LABEL_TAG;
		label.font = [UIFont systemFontOfSize:12.0];
		label.text = [NSString stringWithFormat:@"%d", indexPath.row];
		label.textAlignment = UITextAlignmentRight;
		label.textColor = [UIColor blueColor];
		label.autoresizingMask = UIViewAutoresizingFlexibleRightMargin |
		UIViewAutoresizingFlexibleHeight;
		[cell.contentView addSubview:label]; 
 
		label =  [[[UILabel alloc] initWithFrame:CGRectMake(60.0, 0, 30.0,tableView.rowHeight)] autorelease];
		[cell addColumn:120];
		label.tag = VALUE_TAG;
		label.font = [UIFont systemFontOfSize:12.0];
		// add some silly value
		label.text = [NSString stringWithFormat:@"%d", indexPath.row * 4];
		label.textAlignment = UITextAlignmentRight;
		label.textColor = [UIColor blueColor];
		label.autoresizingMask = UIViewAutoresizingFlexibleRightMargin |
		UIViewAutoresizingFlexibleHeight;
		[cell.contentView addSubview:label];
	}
 
	return cell;
}

 That’s it. Being a bit dense I beat my head on my desk a few days before it become obvious how blindingly simple it really was. A lot was just learning ObjectiveC and how UIKit works in general. I’m now working on a GridTableView library that will add a good bit of functionality and ease of use. I’ll post it here.

 

 怎么在iPhone程序中读取PDF的内容呢?答案是,苹果为我们准备了一个很神奇的framework Q2D(Quartz 2D)。Q2D提供了全套的PDF读取API,接下来我们来看看如果简单的使用Q2D来读取PDF文件:

 我建立了一个工程叫iPhonePDF, 添加了一个UIScrollView(不知道怎么添加UIScrollView? 添加一个UIView然后把interface上的UIView改成UIScrollView就可以啦…)名为PDFView

看看PDFView里面有什么吧

@interface PDFView : UIScrollView {
 NSString *filePath;
 CGPDFDocumentRef pdfDocument;
 CGPDFPageRef page;
 int pageNumber;
}
 
@property (copy, nonatomic) NSString *filePath;
@property int pageNumber;
 
-(CGPDFDocumentRef)MyGetPDFDocumentRef;
-(void)reloadView;
-(IBAction)goUpPage:(id)sender;
-(IBAction)goDownPage:(id)sender;
@end

filePath是储存pdf文件的位置的,得到文件位置就是老话题了:[NSBundle mainBundle]… 后面的会写吧… 不记得了在我博客里面搜索吧

CGPDFDocumentRef是PDF文档索引文件,Q2D是Core Foundation的API,所以没看到那个星星~

CGPDFPageRef是PDF页面索引文件

pageNumber是页码

下面的几个函数其实一看就明了了,翻页的,和刷新页面的。第一个是自定义的getter

然后我们看看m文件里面有用的方法:

@implementation PDFView
@synthesize filePath,pageNumber;
 
- (void)drawRect:(CGRect)rect //只要是UIView都有的绘图函数,基础哟~
{
 if(filePath == nil) //如果没被初始化的话,就初始化
 {
  pageNumber = 10;   //这个其实应该由外部函数控制,不过谁让这个程序特别简单呢
  filePath = [[NSBundle mainBundle] pathForResource:@"zhaomu" ofType:@"pdf"];
                //这里,文件在这里!
  pdfDocument = [self MyGetPDFDocumentRef]; //从自定义getter得到文件索引
 }
 
 CGContextRef myContext = UIGraphicsGetCurrentContext();
        //这个我研究了一段时间呢,不过就照打就可以了
 
 page = CGPDFDocumentGetPage(pdfDocument, pageNumber);
        //便捷函数,告诉人家文档,告诉人家页码,就给你页面索引
 
 CGContextDrawPDFPage(myContext, page);
        //画!
}
 
//此getter可以考虑照打... 都是CF函数,我看到就恶心。
//其实不是很难了,得到文件,转换成URL,然后通过
//CGPDFDocumentCreateWithURL(url)得到文件内容索引
//Ta Daaa~~
- (CGPDFDocumentRef)MyGetPDFDocumentRef
{
 CFStringRef path;
 CFURLRef url;
 CGPDFDocumentRef document;
 path = CFStringCreateWithCString(NULL, [filePath UTF8String], kCFStringEncodingUTF8);
 url = CFURLCreateWithFileSystemPath(NULL, path, kCFURLPOSIXPathStyle, 0);
 CFRelease(path);
 document = CGPDFDocumentCreateWithURL(url);
 CFRelease(url);
 return document;
}
 
-(void)reloadView
{
 [self setNeedsDisplay]; //每次需要重画视图了,就call这个
}
 
-(IBAction)goUpPage:(id)sender
{
 pageNumber++;
 
 [self reloadView];
}
-(IBAction)goDownPage:(id)sender
{
 pageNumber--;
 [self reloadView];
}
@end

 

CoreData实例分析学习(1)

2009年12月15日 23:00

 Core Data是个好东西,在数据储存操作上速度快,容易操作,是一种类似关系数据库的东西。但是有些不那么好学,那到底Core Data是怎么操作的呢?怎么用呢?怎么来编程呢?我们一起来学习吧,接下来使用苹果提供的实例程序Locations来作分析:

 

>程序介绍:

右侧是改程序的截图,基本上来说就是通过使用Core Location来得到当时的位置,然后在点击“+”的时候记录下当时的经纬度。通过UITableViewController的功能来添加,编辑,删除等功能。整体程序使用Core Data来储存数据,实体(Entity)为一个位置,包括以下参数:1,时间(收集数据的时间)2,纬度,3,经度

首先我们看看该程序的AppDelegate.h

  1. @interface LocationsAppDelegate : NSObject  {
  2.     UIWindow *window;
  3.     UINavigationController *navigationController; //导航栏
  4.  
  5.     //以下定义了Core Data的三个决定性组建,等后面m文件里面再多介绍
  6.     NSPersistentStoreCoordinator *persistentStoreCoordinator;
  7.     NSManagedObjectModel *managedObjectModel;
  8.     NSManagedObjectContext *managedObjectContext;
  9. }
  10.  
  11. @property (nonatomic, retain) IBOutlet UIWindow *window;
  12. @property (nonatomic, retain) UINavigationController *navigationController;
  13.  
  14. - (IBAction)saveAction:sender; //这个没找到作用...根本就没用到IB
  15.  
  16. //还记得吧,nonatomic是因为这个程序是单线程
  17. @property (nonatomic, retain, readonly) NSManagedObjectModel *managedObjectModel;
  18. @property (nonatomic, retain, readonly) NSManagedObjectContext *managedObjectContext;
  19. @property (nonatomic, retain, readonly) NSPersistentStoreCoordinator
  20.                               *persistentStoreCoordinator;
  21. @property (nonatomic, readonly) NSString *applicationDocumentsDirectory;
  22. //程序文档目录是主要为了给NSPersistentStoreCoordinator找个存SQLite文件的地方
  23. @end

  

从上面的我们能看出来,该程序是通过一个根Core Data数据管理来管理整个程序的CoreData数据的,接下来看m文件也会对此作更多的理解。

 

  1. #import "LocationsAppDelegate.h"
  2. #import "RootViewController.h" //该程序使用了一个根视图控制器,所以导入了这个类
  3. @implementation LocationsAppDelegate
  4. @synthesize window;
  5. @synthesize navigationController;
  6.  
  7. - (void)applicationDidFinishLaunching:(UIApplication *)application {
  8.         //初始化根视图控制器,它是一个列表视图控制器
  9.         RootViewController *rootViewController = [[RootViewController alloc]
  10.              initWithStyle:UITableViewStylePlain];
  11.  
  12.         //通过下面的自定义getter得到CoreData的“被管理对象内容器”
  13.         NSManagedObjectContext *context = [self managedObjectContext];
  14.         if (!context) {
  15.                 // 如果getter出错,在这里来排错
  16.         }
  17.         rootViewController.managedObjectContext = context;
  18.         //rootViewController有一个本地“被管理对象内容器”,在这里赋值过去
  19.  
  20.         UINavigationController *aNavigationController = [[UINavigationController alloc]
  21.              initWithRootViewController:rootViewController];
  22.         self.navigationController = aNavigationController;
  23.         //初始化导航栏,根视图为rootViewController,并指定该导航栏为程序导航栏
  24.         [window addSubview:[navigationController view]];
  25.         [window makeKeyAndVisible];
  26.  
  27.         //由于导航栏retain了根视图,所以在这里可以release掉它了
  28.         [rootViewController release];
  29.         //由于self已经retain了导航栏,所以导航栏可以release
  30.         [aNavigationController release];
  31. }
  32.  
  33. //applicationWillTerminate: 在程序结束前,Core Data会保存任何对其的更改
  34. - (void)applicationWillTerminate:(UIApplication *)application {
  35.  
  36.     NSError *error;
  37.     if (managedObjectContext != nil) {
  38.         if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) {
  39.                         // Handle the error.
  40.         }
  41.     }
  42. }
  43.  
  44. //在得到点击事件后,保存更改
  45. - (IBAction)saveAction:(id)sender {
  46.  
  47.     NSError *error;
  48.     if (![[self managedObjectContext] save:&error]) {
  49.                 // Handle error
  50.     }
  51. }
  52.  
  53. //自定义的managedObjectContext的getter, 它其实是真正在使用的时候的被操作对象
  54. - (NSManagedObjectContext *) managedObjectContext {
  55.  
  56.     //如果已经有这个对象,就直接返回,否则继续
  57.     if (managedObjectContext != nil) {
  58.         return managedObjectContext;
  59.     }
  60.  
  61.     NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
  62.     if (coordinator != nil) {
  63.         managedObjectContext = [[NSManagedObjectContext alloc] init];
  64.         [managedObjectContext setPersistentStoreCoordinator: coordinator];
  65.        //这里可以看到,“内容管理器”和“数据一致性存储器”的关系,
  66.        //managedObjectContext需要得到这个“数据一致性存储器”
  67.     }
  68.     return managedObjectContext;
  69. }
  70.  
  71. //自定义的CoreData数据模板的getter,数据模板其实就是一个描述实体与实体的关系
  72. //,类似于关系型数据库的关系描述文件
  73. - (NSManagedObjectModel *)managedObjectModel {
  74.  
  75.     if (managedObjectModel != nil) {
  76.         return managedObjectModel;
  77.     }
  78.     managedObjectModel = [[NSManagedObjectModel mergedModelFromBundles:nil] retain];
  79.     //从本地所有xcdatamodel文件得到这个CoreData数据模板
  80.     return managedObjectModel;
  81. }
  82.  
  83. //自定义“数据一致性存储器” persistentStoreCoordinator的getter
  84. - (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
  85.  
  86.     if (persistentStoreCoordinator != nil) {
  87.         return persistentStoreCoordinator;
  88.     }
  89.  
  90.     //定义一个本地地址到NSURL,用来存储那个SQLite文件
  91.     NSURL *storeUrl = [NSURL fileURLWithPath:
  92.             [[self applicationDocumentsDirectory]
  93.                             stringByAppendingPathComponent: @"Locations.sqlite"]];
  94.  
  95.         NSError *error;
  96.     persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc]
  97.             initWithManagedObjectModel: [self managedObjectModel]];
  98.     //从这里可以看出,其实persistentStoreCoordinator需要的不过是一个
  99.     //存储数据的位置,它是负责管理CoreData如何储存数据的
  100.     if (![persistentStoreCoordinator
  101.         addPersistentStoreWithType:NSSQLiteStoreType
  102.         configuration:nil
  103.         URL:storeUrl
  104.         options:nil
  105.         error:&error]) {
  106.         // Handle the error.
  107.     }   
  108.  
  109.     return persistentStoreCoordinator;
  110. }
  111.  
  112. //返回该程序的档案目录,用来简单使用
  113. - (NSString *)applicationDocumentsDirectory {
  114.  
  115.     NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
  116.                             NSUserDomainMask, YES);
  117.     NSString *basePath = ([paths count] > 0) ? [paths objectAtIndex:0] : nil;
  118.     return basePath;
  119.     //我原来的帖子中介绍过,方法其实是一模一样的
  120. }
  121.  
  122. - (void)dealloc {
  123.  
  124.     //释放内存
  125.     [managedObjectContext release];
  126.     [managedObjectModel release];
  127.     [persistentStoreCoordinator release];
  128.  
  129.         [navigationController release];
  130.         [window release];
  131.         [super dealloc];
  132. }
  133. @end

 

从上面的程序主代理文件可以看出,CoreData的简单使用不过是通过三个组建。

NSManagedObjectModel来描述实体与实体的关系,也就是类似于表和表的关系。
NSManagedObjectContext来得到被储存内容的文件管理器,对数据作直接操作
NSPersistentStoreCoordinator来管理数据的储存位置,储存方法(SQLite)

你对Core Data理解更多了么?

 

补一下“实体”的概念,实体也就是Entity,在打开xcdatamodel文件的时候,我们可以看到

屏幕快照 2009-08-26 下午05.08.29

在这里,这个实体叫“Event”,而实体的参数有“创建日期”,“纬度”,“经度”。也就是说,其实这个实体被使用后,我们可以这样理解,实体就是表名,而参数就是列名,然后整个实体就是一张表。当这个Model描述多个实体的关系的时候,就像是一个关系型数据库一样,虽然苹果说“不是!”