Roadmap Chapter 1 explains the iOS SDK, introducing the new options in iOS four and covers how to put in the iOS SDK. Chapter 2 kicks things off by highlighting Objective-C, which is the programming language used on the iPhone SDK. Chapter 3 looks at Xcode four, the newly released device in iOS SDK. This built-in growth setting does more than simply compile your code. It also helps you right simple errors as you type and provides fast, built-in entry to all the iPhone programming documents. Chapter 4 shifts the focus to mastering Xcode by writing code for applications and debugging with Xcode. Chapter 6 steps again to speak about consumer interplay. It covers occasions, which customers generate by touching the display with a quantity of fingers, and actions, which occur when users work together with a management object like a button or a slider. Chapter 7 finishes our have a glance at view controllers by inspecting two more-advanced potentialities. The tab bar view controller allows for modal choice between multiple pages of content material, and the navigation view controller adds hierarchy to tables. Also the universal application design idea will be lined. Chapter 8 opens the SDK toolkit by speaking about knowledge.
This consists of person input, corresponding to actions and preferences; knowledge storage, such as information; and instruments that combine input and storage, such as the devices' tackle book. In this chapter, you discover methods to retailer advanced knowledge in an SQLite database or by utilizing Core Data. Chapter 10 highlights two of the most distinctive features on the iPhone and iPad— the accelerometer and the GPS—showing how the iPhone can track movement via area. Chapter eleven covers one other of the device's strengths—media—by displaying how to do basic work with photos, films, and sound. It discusses how to play and record audio using a device's microphone and audio system. Chapter 14 examines how you can use the iPhone and iPad to interact with the web. This chapter strikes through the whole hierarchy of web communication, from low-level host connections to URLs, from internet views to modern social languages like XML and JSON. The anatomy of iOS iOS's frameworks are divided into four major layers, as shown in figure 1.4. Each of these layers incorporates a wide range of frameworks that Cocoa Touch you possibly can access when writing iOS SDK applications. Generally, you must favor the higher-level layers when you're codMedia ing . Cocoa Touch is the framework that you'll turn out to be most Core Services conversant in. It incorporates the UIKit framework—which is Core OS what we spend most of our time on on this book—and the Address Book UI framework. UIKit consists of window assist, event help, and user-interface administration, and it Figure 1.4 Apple supplies you with four layers of enables you to show each text and web pages. It additional acts as frameworks to use when your interface to the accelerometers, the digicam, the picture writing iOS applications. Media is where you can get entry to the most important audio and video protocols built into the iPhone and iPad. Its 4 graphical technologies are OpenGL ES, EAGL , Quartz (which is Apple's vectorbased drawing engine), and Core Animation . Other frameworks of note include Core Audio, Open Audio Library, and Media Player. Core Services presents the frameworks utilized in all functions.
Many of them are information related, similar to the interior Address Book framework. Core Services also contains the critical Foundation framework, which includes the core definitions of Apple's objectoriented knowledge varieties, corresponding to its arrays and sets. You can access threading, recordsdata, networking, other low-level I/O, and memory functions. Most of your programming work might be accomplished utilizing the UIKit or Foundation framework. The overwhelming majority of code in this book might be built solely using Cocoa Touch. But you'll generally have to fall again on libraries that are instead based mostly on simple C functionality. Examples embrace Apple's Quartz 2D and Address Book frameworks, in addition to third-party libraries like SQLite. Expect object creation, memory administration, and even variable creation to work differently for these non-Cocoa libraries. This will provide you with a complete fundamental software, together with a easy information set. You'll stroll by way of the code and modify it to show a list of web site bookmarks. When the person faucets the bookmark within the left pane, it's going to load the website in the right one. As you modify the code, we'll clarify intimately how the SplitViewController is constructed. Figure 7.11 reveals what the applying will look like. When you first create a split view–based application, a number of recordsdata are added to your project mechanically. Figure 7.12 exhibits the varied view parts you see when you click the SplitViewController. As you probably can see, the SplitViewController is made up of two main views. The navigation bar within the left view ought to hint that its view is a navigation controller. The object viewer in the backside corner confirms this. Notice that the view hierarchy is exactly the same as that for the navigation controller in part 7.2. The right view is loaded from one other nib referred to as DetailView.
Double-clicking the blue textual content labeled DetailView opens it and lets you modify it as you'll some other view. You'll see that later in the section whenever you add a web view to the instance software. Media Layer—Frameworks for adding audio, video, graphics and animations to your apps. Audio Toolbox Interface for audio recording and playback of streamed audio and alerts. Audio Unit Interface for opening, connecting and utilizing the iPhone OS audio processing plug-ins. AV Foundation Interface for audio recording and playback . Used in Chapter 7's Spot-On Game app and Chapter 8's Cannon Game app. Core Audio Framework for declaring data types and constants used by different Core Audio interfaces. Core Graphics API for drawing, rendering photographs, color administration, gradients, coordinate-space transformations and handling PDF documents. Media Player Finds and plays audio and video files within an app. OpenGL ES Supports integration with the Core Animation layer and UIKit views.
Subset of the OpenGL API for 2D and 3D drawing on embedded methods. Quartz Core Framework for picture and video processing, and animation utilizing the Core Animation technology. Core Services Layer—Frameworks for accessing core iPhone OS three.x services. Address Book Used to access the consumer's Address Book contacts. Core Data Framework for performing tasks associated to object life-cycle and object graph management. Core Foundation Library of programming interfaces that enable frameworks and libraries to share code and information. Introduced in Chapter 5's Favorite Twitter Searches app and used all through the book. Core Location Used to discover out the placement and orientation of an iPhone, then configure and schedule the supply of location-based occasions. Foundation Includes NSObject , plus instruments for creating graphical, event-driven apps. Also consists of design patterns and features for making your apps extra efficient. Mobile Core Services Includes commonplace types and constants. Creating a navigation controller To create a navigation controller, create a model new project utilizing the Navigation-Based Application template. You can web page through the .xib file and the Xcode listing to see what you're given. Let's start with the .xib information, whose content material you can see in figure 7.5. Mainwindow.xib contains a UINavigationController within the nib window with a UINavigationBar hidden underneath it. The primary display window accommodates a UINavigationItem and a RootViewController. The latter is a subclass of UIViewController created through Xcode, just as when you designed your individual desk controller in chapter 5. Note that this units up the usual iPhone paradigm of navigation controllers being built atop table controllers. The desk view controller's contents are instantiated by way of a second .xib file, RootViewController.xib, as proven in the table view controller's attributes window.
RootViewController.xib is a boring .xib file as a result of it incorporates solely a table view. Consider it a great instance of how pairing .xib information with view controllers can keep your program properly organized. A Tab Bar Application creates a tab bar alongside the bottom of the display screen that allows you to change between multiple views. The template does this by creating a tab bar controller and then defining what each of its views looks like. A Utility Application defines a flip-side controller that has two sides, the front facet containing an data button that permits you to name up the bottom. This is the last view controller we'll explore in chapter 7. An OpenGL ES Application is one other minimalistic software. The difference from the Window-Based Application is that it consists of GL frameworks, sends the glView messages to get it started, and otherwise units certain GL properties. We won't get to GL till chapter 13, and even then we'll only touch on it frivolously. A Split View-Based Application is a split view controller–based software that works only on the iPad. In addition, you want to autoplayback this music file 10 instances and set the delegate to self. Then inside the audio session 1#, you define the class as AVAudioSessionCategoryPlayback to inform the system that this software will use audio enjoying as a main operate. Finally, you launch the retained objects inside the dealloc 1$. Change the target to a universal utility for each iPhone and iPad. Save all the adjustments, click Build, and run it in Xcode. The text label will show the audio file's name, as proven in determine 22.three. Play with this utility a bit, and you will discover that our utility has the primary precedence in audio taking half in. When you've an incoming phone call, this application will pause playing the current music as defined within the interruption-handling methods.
In the header file, you add in a single label for the filename and three buttons for the audio taking half in control. Three strategies are defined to handle each button's contact occasion. Next, let's add the new objects to the nib file and join them to the view controller's header file. Click the MySongViewController.xib file to open it for modifying, and then open the item library. First, add a model new textual content label into the view, after which drag three buttons into the view. By default, the button's sort is a rounded rectangle. Let's change the button's attributes to a customized type and assign the background image to each button. Once it's complete, you'll see the view controller's UI, similar to the one proven in figure 22.2. Single-click the file's owner under the MySongViewController's File panel. Go to the connection inspector and ensure all four UI outlets in the file's owner are linked to new subviews. Hook up the three motion buttons and save every little thing. Now we'll move on to implement the MySongViewController.m file. There are many changes within the next step, contemplating this may be a complete audio taking half in project. You begin by initializing the media player and picker. Because the participant is being initialized with the iPodMusicPlayer method, the applying uses the global iPod player when playing media gadgets. The media picker is initialized with the MPMediaTypeAnyAudio fixed; this lets the user select any type of audio media from the iPod library. Finally, you set the category because the delegate to the MPMediaPickerController so you'll be able to reply to its actions.
The mediaPicker method known as mechanically each time the person selects an audio item from the iPod library. It receives an MPMediaItemCollection, which incorporates the audio item to be performed. The subsequent line takes this collection and provides it to the iPod media collection's queue. To disguise the picker, you name dismissModalViewControllerAnimated. The pickMedia technique shows the media picker on prime of the current view. The playMedia and stopMedia strategies are fairly self-explanatory as a result of they solely control the media participant. Use these methods as a template for implementing other media participant controls on your own. Finally, you have to make sure to release objects that you allocate. Doing so ensures that your utility doesn't use extra reminiscence than it wants and runs as effectively as attainable. In the next section, we'll discuss how to let customers document audio files. Figure 2.2 lists a variety of the many recommendations that appear in the 130-page doc IPhone Human Interface Guidelines. Points and Suggestions from the iPhone Human Interface Guidelines • Most necessary, read the doc IPhone Human Interface Guidelines. • If you're going to create net applications, additionally read the document iPhone Human Interface Guidelines for Web Applications. • Keep in mind that iPhone apps are designed in a special way from desktop apps due to the small screen. • Design your app to work well on condition that the iPhone shows only a single display screen at a time. • Keep in mind that the iPhone runs only one app at a time. Leaving an app quits the app, so be positive to save something you want immediately after it's created.
• Your app ought to be modeled after the way in which things work in the actual world. • People feel nearer to your app's interface as a result of they contact it directly . • Give individuals lists and let them contact the selection they want somewhat than requiring key stroking, if potential. • Provide suggestions to person actions—for example, use an activity indicator to level out that an app is engaged on a task of unpredictable duration. • Be consistent—for example, all the time prefer commonplace buttons and icons offered by the iPhone OS to creating your own custom-made buttons and icons. • If you do present customized icons, ensure that they're easily distinguishable from system icons. • Although you can have as many buttons as you want on alerts, you must present two. Avoid the complexity of alerts with greater than two buttons. • Your apps ought to be intuitive—the person ought to be ready to work out what to do at any given time, with minimal assist. • Support the standard iPhone gestures in the usual way. • Make your apps accessible for folks with disabilities. • If a button does something harmful, make it red. You can almost consider the AV Foundation framework as a raw API—very low stage in comparison with a variety of the different frameworks we've coated.
AV Foundation offers you all of the instruments and APIs you have to create your own options, but generally building a house from the bottom up can be a lot extra work than needed. For those who don't want a custom answer, Apple has created two normal media seize and media participant view controllers, UIImagePickerController and MPMoviePlayerController. This allows the chat shopper to periodically ping the server to verify whether the user has acquired any new chat messages. The elegant solution that Apple got here up with is called push notification. A push notification is an easy message that originates at a push provider, containing data related to a particular program. These messages can contain any number of things, together with a message, a sound file to play, a badge count, and any customized key-value pair needed for an utility. Figure 17.1 shows an instance of what a push notification would possibly seem like for an software. As you presumably can see within the determine, the push notification seems similar to a text message. The title is the title of the applying that the push notification is said to. When the consumer taps the View button, the iPhone or iPad launches the appliance that invoked the push notification. It should turn out to be obvious how this approach solves the problem of background processing for most purposes. In the case of an instant message program, users can decide to remain on-line through the chat server. That means, they will exit the applying and the server can push notifications any time they receive a new chat message. Users don't need to waste system memory having their chat shopper run within the background, pinging the server for brand spanking new messages. Push notifications are simple to incorporate in your functions, as a result of little code is required. One problem is the fact that in addition to enabling your functions for push notifications, you have to additionally create a push supplier. We'll talk about each of those aspects of the system and present you how to create a full system for sending and receiving push notifications. Push notification has been a great service since iOS three, nevertheless it solely works when the iPhone or iPad is related to the web.
