驾驶题库 1.2 发布
2010年2月04日 06:53
Happy iPhone coding
The original paper comes from: http://www.cocoadev.com/index.pl?SortUsingSelector
sortUsingSelector is an instance method of NSMutableArray
What should the structure of a function be when it will be called by sortUsingSelector:?
The method selector you pass in should specify a method that returns an NSComparisonResult? (either NSOrderedAscending?, NSOrderedSame?, or NSOrderedDescending?), just like the compare: method that everything responds to. If your NSMutableArray is full of NSStrings? or NSNumbers?, you can just do:
[myArray sortUsingSelector:@selector(compare:)];
and it will sort them appropriately because NSString and NSNumber both properly implement compare:. The idea is that every class should implement a compare: method that makes the receiver compare itself and return the right result.
sortUsingSelector: gets more interesting when you have objects that aren't simply strings or numbers. For instance, let's say I have a class Person with instance variables (and corresponding accessor methods) firstName and lastName whose objects I want to be able to sort by name (in the form "Last, First"). I can implement something like this:
- (NSComparisonResult)comparePerson:(Person *)p { return [[NSString stringWithFormat:@"%@, %@", [self lastName], [self firstName]] compare: [NSString stringWithFormat:@"%@, %@", [p lastName], [p firstName]]; }
Using this method with sortUsingSelector: will sort all Nelsons before all Smiths, and Abby Smith before Bernard Smith.
Of course, you can make things more flexible by deferring the sort order until runtime. Sometimes you may want to sort by first name instead of last name. In this case, the best thing to do is probably something like this:
- (NSComparisonResult)comparePerson:(Person *)p { return [[self stringForSorting] compare:[p stringForSorting]]; } - (NSString *)stringForSorting { if (something) // determine sorting type here return [NSString stringWithFormat:@"%@, %@", [self lastName], [self firstName]]; // else... return [NSString stringWithFormat:@"%@ %@", [self firstName], [self lastName]]; }
You would replace the "if (something)" condition with something useful; maybe check a user preference, or the state of something in the GUI.
-- JackNutting
Is this any different from sortUsingFunction? They seems just about the same, except with different paramaters
It is similar, but there is one important advantage to -sortUsingFunction:context:, it allows you to send in a "context" pointer, which allows you to build a sorting function that accepts some info to help control the sorting. This can be a pointer to anything at all, but in practice I find it most useful for sending in an NSString that will specify a method to base the sorting on.
To extend our previous example: We had set things up there so that the Person object could control the way the sorting was done (lastname or firstname). Let's say that we want that control to happen not in the Person class itself, but in the "user" of the Person (perhaps we've got a PersonListView?) or something).
To do this, we can implement a sorting function that accepts a "context" paremeter that allows us to specify the method used to determine sort order for the objects we're looking at. For example, we might like to be able do things like:
[personArray sortUsingFunction:comparePersonsUsingSelector context:@"lastName"]; [personArray sortUsingFunction:comparePersonsUsingSelector context:@"firstName"];
In this case we're passing in an NSString as a context to tell our function the name of the method that should be used for sorting. The function implementation would then be something like this:
static int comparePersonsUsingSelector(id p1, id p2, void *context) { // cast context to what we know it really is: an NSString NSString *methodName = context; SEL methodSelector = NSSelectorFromString(methodName); id value1 = objc_msgSend(p1, methodSelector); id value2 = objc_msgSend(p2, methodSelector); return [value1 compare:value2]; }
Note that in real code you'd want to have some error-checking here, for example making sure that the "context" passed into the function is really an NSString, making sure that p1 and p2 both respond to methodSelector, etc.
The extra functionality you get with -sortUsingFunction:context: could easily be provided in a method-based form by implementing something like -sortUsingSelector:context:; why Apple didn't include it is a mystery to me. Maybe as an "exercise for the reader"?
A simplification of the example above: pass a SEL as the context, instead of an NSString *. I've also used -[NSObject performSelector:] instead of calling objc_msgSend() directly.
[personArray sortUsingFunction:comparePersonsUsingSelector context:@selector(lastName)]; [personArray sortUsingFunction:comparePersonsUsingSelector context:@selector(firstName)]; static int comparePersonsUsingSelector(id p1, id p2, void *context) { // cast context to what we know it really is: a SEL SEL methodSelector = (SEL)context; id value1 = [p1 performSelector:methodSelector]; id value2 = [p2 performSelector:methodSelector]; return [value1 compare:value2]; }
-- Greg Parker
Advanced Sorting Techniques
Let's say you've got an array of animal objects. Each animal can be a Dog, Cat, Bird, or Fish. Now, you want to keep them sorted by kind, but within each group, you want them sorted by name also. Here's a sort method for doing something like this:
// example enum typedef enum { AnimalDog, AnimalCat, AnimalBird, AnimalFish } AnimalKind; // example class interface @interface Animal : NSObject { NSString *animalName; AnimalKind animalKind; } - (NSString *)name; - (AnimalKind)kind; @end - (NSComparisonResult)compare:(Animal *)otherAnimal { // comparing the same type of animal, so sort by name if ([self kindOfAnimal] == [otherAnimal kindOfAnimal]) return [[self name] caseInsensitiveCompare:[otherAnimal name]]; // we're comparing by kind of animal now. they will be sorted // by the order in which you declared the types in your enum // (Dogs first, then Cats, Birds, Fish, etc) return [[NSNumber numberWithInt:[self kindOfAnimal]] compare:[NSNumber numberWithInt:[otherAnimal kindOfAnimal]]]; }
Aarrgghh. Excessive object orientation alert. Creating two NSNumbers from your ints and then sending them a compare: message is a rather baroque way to find out the ordering of two integers.
原文来自:http://iphone.ipsw.info/2009/10/nsmutablearray.html
- (NSArray *)sortedArrayUsingSelector:(SEL)comparator
A selector that identifies the method to use to compare two elements at a time. The method should return @property (nonatomic, readwrite, retain) 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 allValues] sortedArrayUsingFunction:sortObjectsByLatestTimecontext:NULL]; } ////////////////////////////////////////////////////////// sortUsingDescriptors:适合元素是dict类型,initWithKey既是dict key. NSMutableArray *regions = [NSMutableArray array]; NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES]; NSArray *sortDescriptors = [NSArray arrayWithObject:sortDescriptor]; [regions sortUsingDescriptors:sortDescriptors]; [sortDescriptor release];Parameters
NSOrderedAscending
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:)];
The Original paper come from: http://www.webdesignerdepot.com/2009/05/how-to-get-started-with-iphone-dev/
The iPhone is a fantastic phenomenon. It’s a communications device, a multimedia platform and much more all rolled into one single tool. Everyone wants in on this device.
The Apple store has just passed the one billionth application download (I alone account for 3% of that…) and there is a wide array of applications from the amazingly useful to the bizarrely redundant.
With millions of iPhones out there, it makes sense to have your content, or application available on that platform, but how do you go about doing this? Where do you go to get started? And what are the steps you need to take to get there?
This article is an introduction to the various ways of getting content and applications onto the iPhone. It is by no means a full guide, but hopes to point you in the right direction and give you an overview of what is involved in the process.
The first step in writing for the iPhone is understanding how things really work on the iPhone. I think it is virtually impossible to develop for the iPhone without being a solid user for a while.
The iPhone has a certain way of doing things and if your content does not adhere to that it will stick out like a sore thumb. It is very different to what happens on a desktop.
The only means of interacting with content on the iPhone is your fingers. This dictates a lot of the way the interface works. The other major differences are that the screen is small, only one application runs at a time and there is very little opportunity to provide user help.
The iPhone uses animation extensively to provide a fluid, responsive interface that feels almost physical (as if the screen’s contents are really moving off, jumping or collapsing). You really need to get a feel for this to be able to create something that lives comfortably on the iPhone.
You could potentially use the iPhone simulator on a Mac instead of an actual iPhone or iPod Touch, but… that doesn’t really do it. The iPhone has a set of accelerometers that can sense the orientation and movement of the device. You really need to hold it and feel it.
Apple provides a wealth of information on its iPhone developer site:
http://developer.apple.com/iphone/
There are introductory videos, documents and sample code. Besides all the introductory material, a great document to start with is the iPhone user interface guidelines.
They can be found here:http://developer.apple.com/iphone/library/documentation/UserExperience/Conceptual/MobileHIG/MobileHIG.pdf
I highly recommend starting out with this document. It has examples and sets you out on the voyage. Familiarize yourself with the way things are done on the iPhone and the arsenal of controls and functionality at your disposal.
I’m not going to go deeply into this. Planning on the iPhone is like planning for any other platform.
You need to be clear about what you want to achieve and explore what functionality you want to expose with your project. Strive for a solution that is clear, understandable, visually pleasing and of course… cool.
Once you know the game plan the search starts for the design. With the unique iPhone look, it is essential that you use that look in visualizing your project’s interface.
Recreating the iPhone interface for wireframe or sketch purposes is a lot of work. Fortunately people have already put in that effort and it is available for you to use.
These are collections of graphical widgets in various formats that can be used to assemble what looks like iPhone screens. You can use them to put together sketches and wireframes for your projects. Here are a few:
Part of the Yahoo UI Kit. This is an excellent resource for any kind of UI design visualization. The Yahoo! Design Stencil Kit version 1.0 is available for OmniGraffle, Visio (XML), Adobe Illustrator (PDF and SVG), and Adobe Photoshop (PNG). It is a set of graphics in different formats to be used in various applications and help you put together UI sketches.
Download here: http://developer.yahoo.com/ypatterns/wireframes/
A Photoshop file that has a fairly comprehensive library of assets, some editable
Download here: http://teehanlax.com/downloads/iPhone_GUI.psd.zip
A PDF or Photoshop based ’sketchepad’ for sketching out iPhone interfaces.
It can be downloaded here: http://labs.boulevart.be/index.php/2008/06/05/sketch-paper-for-the-mobile-designer/
And of course, there are several others floating around.
OK. So now you have an idea or some content, you thought of the game plan, you sketched out an interface that would look at home on the iPhone. What’s next? Well…there are several approaches you can take to get your project on the iPhone:
The iPhone has a remarkable web browser for a mobile device: Safari. It has a few tricks up its sleeves and does its best to present any website in a readable fashion. So… if you have a website that is up and running, you might get away with doing absolutely nothing.
Safari is able to present nearly any website in a readable way. The user can double click on any section of the web page and Safari will zoom in to a readable scale and present that page.
Things that are to be avoided for iPhone compliance are:
So if your site/app works well with Safari on the iPhone with no changes, that is your path of least resistance.
The next step up is to keep your site, but make a few adjustments, so that viewing it on an iPhone will be a better experience for your visitors.
Here some some simple tips and trick that will make your site work well for an iPhone visitor.
Now you’re talking! You are going to develop a website specifically for the iPhone. You need to learn what is possible from here http://developer.apple.com/safari/mobile.php and start putting it all together.
The idea is to build a web app that lives comfortably on the iPhone, preserves the visual style and behaviors the iPhone users are used to and takes advantage of the special features of the platform such as gestures, orientation changes, etc.
You don’t have to start from scratch. There are plenty of great resources that provide a good starting point or framework to build your iPhone:
Using the Aptana Studio iPhone template / Code view
Aptana Studio showing iPhone preview
Various sites developed specifically for the iPhone
Various sites developed specifically for the iPhone
The following options involve the Apple Developer tools. To access them you need to be a registered Apple developer. The suite of tools is collectively called Xcode. Xcode includes a number of tools, each tackles a different part of the puzzle:
Signing up is done here: http://developer.apple.com/
Dashcode is a strange beast. It’s part of the Xcode suite, but does not really interact with the other components (except for the iPhone simulator it uses to run projects you develop with it).
Dashcode is an IDE geared to building iPhone web apps. It has a number of templates you can use as a starting point for your app (Navigation based application, Tab bar based application etc) and take it from there.
There is a control library that you can use, dragging out controls onto your interface and then assigning properties and logic.
Dashcode saves its projects as a Dashcode project file, and when you are done you export the project as an html/javascript/css site for deployment.
It isn’t built for very elaborate complicated apps that have a lot of backend code, but if you have a straightforward self contained idea. There is nothing faster than Dashcode for putting it together.
The user guide to Dashcode can be found here
The Dashcode IDE, providing a library of controls a layout area and code editing section
Previewing a site developed in Dashcode on the iPhone simulator
Using all that webkit can offer along with one of the frameworks, or building your site using DashCode allows you to create something very close to a native iPhone app that is sensitive to orientation changes, uses animation for transitions and displays the iPhone UI widgets. What you will be missing is this:
To gain the full leverage of the app store and to take full advantage of all the iPhone has to offer, you need to use the iPhone SDK.
Creating an iPhone SDK app exposes the full potential of the iPhone. The SDK provides an incredibly rich collection of frameworks each responsible for a particular area of functionality.
The big picture is like this: You create an application in Xcode, build the user interface in Interface Builder and run it in the iPhone Simulator.
The main framework that you most likely will become most familiar with is Cocoa Touch. Among other things it contains the UIKit framework and the address book UI framework. It also supports windowing, events and user-interface management plus much more.
There is a lot of heavy lifting to be done here and a lot of information to be absorbed in order to take advantage of the richness the iPhone provides.
Fortunately there is tons of information, documentation, sample code and introduction videos available here: http://developer.apple.com/iphone/
The main concepts that you need to wrap your head around are:
Xcode provides many project templates that you can use as a starting point for the major categories of applications: Navigation based application, Tab Bar Application etc.
The first step to starting with SDK development is to download the SDK and install it. The SDK is a hefty 1GB download and requires registration as an Apple developer.
The second step is to figure out what’s going on and get your bearings within this environment. The introductory videos are a good place to start and get oriented.
You can find them here:
http://developer.apple.com/iphone/index.action
Xcode. The nerve center of the IDE development flow
Interface Builder. The tool you use to visually lay out the iPhone app interface
This last type is basically an SDK app with a twist. Sections of the app are actually Safari browser panes that are showing web pages.
This splits the development into the section that will be written using Xcode and objective c and the section that will be fetching information from the web and and presenting it in a browser view.
Basically Xcode will be used to create the application running on the iPhone and Dashcode will be used to build the web sections of the app. Your application is the combination of these two technologies cooperating.
A good reference for this type of app can be found in the user interface guidelines
To sum all this up, let’s look at the most important elements needed to create content for the iPhone:
Written exclusively for WDD by Etan Rozin. He’s a user interface designer and runs his own website at: www.rozin.com
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.
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.
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.
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.
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
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
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。
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
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!”