Topics in Mobile Computing

Transcription

1 Topics in Mobile Computing Workshop 1I - ios Fundamental Prepared by Y.H. KWOK

2 What is ios? From Wikipedia ( ios is an operating system for iphone, ipad and Apple TV. It is derived from MacOS X and developed by the Apple Inc. The user interface of ios is based on the concept of direct manipulation, using multi-touch gestures. The response to user input is immediate and provides a fluid interface. Interaction with the OS includes gestures such as swipe, tap, pinch, and reverse pinch, all of which have specific definitions within the context of the ios operating system and its multitouch interface. Internal accelerometers are used by some applications to respond to shaking the device (one common result is the undo command) or rotating it in three dimensions (one common result is switching from portrait to landscape mode).

3 What is ios? ios is... OS for iphone and ipad Based on MacOS X ( Unix based, Supports File system, network, multithread and etc) Can extends its functionality by writing app using Objective-C, C or C++ languages App can be sold/bought through itunes App Store provided by App.

4 ios Overview Know the structure of ios

5 iphone OS Overview ios Cocoa Touch Media Core Service Core OS

6 Cocoa Touch ios Cocoa Touch You will play with it frequently! Media Core Service Core OS

7 Media ios Cocoa Touch Gaming Audio Media Core Service Core OS 2D Image Manipulation

8 Core Services GPS ios Cocoa Touch Media bonjour Core Service Core OS

9 Core OS ios Cocoa Touch Media Core Service Core OS

10 More new frameworks In IOS 4, it added... GameKit: P2P connection, GameCenter iad: online advertising AVFoundation: advanced camera/audio manipulation AssetLibrary: itunes library, Photo library In IOS5, it added Twitter Integration Core Image and etc

11 ios Development Development Tools & Languages

12 Programming Language You need the following knowledge before start developing your android app: Objective-C - an official programming language for developing ios app, most programming packages are developed with Obj-C and it is supported by Apple. Object Oriented Programming concept - All components of android app are treated in object domain. You have to under how OOP works in order to avoid getting confused. Frameworks - ios app components (i.e., GPS, Networking and etc.) are packed in different frameworks. You have to know how to import other frameworks. (Three core frameworks are imported automatically)

13 Development Tools To create ios App, you need the following tools MacOS X (10.6+), the only platform for development XCode 4, a well-developed IDE with GUI editor for Mac and ios App Development Manage App Resources Coding User interface Design

14 Download Setup Guide There are two ways to get XCode from Apple 1. Mac App Store 1. Register Apple ID. 2. Search XCode 4 from App Store and download it. 2. Download From App Develop 1. Register App ID and Developer Account from: developer.apple.com/ -> ios Dev Center 2. Activate your account. 3. Login into developer page listed on Step one. 4. Download XCode from Download section. 3. Mount the disk image downloaded (dmg) and install the package.

15 Important Tools Tool assisting making apps

16 MacOS X - Dev Platform Menu Bar for all applications Text Quick access to Documents foler Quick access to Applications folder Finder - My Computer of Mac

17 MacOS X - Dev Platform After installation, different from normal application, XCode is located at /Developer/Applications/

18 MacOS X - Hot key Command is similar to Ctrl in windows Basic Hot-keys Copy: Cmd + C Paste: Cmd + V Quit App: Cmd + Q Close windows: Cmd + W

19 Tools - XCode (Code Editor) Build and Run Options Code Editor Project Navigator (Manage Resources) Logging and Error Tracing Area

20 Tools - XCode (Code Editor) Project - packed in a folder Source Code Area Resources folder. (Not restricted) i.e., images, interface files. Imported framework ****It s not necessary to put the files into correct folder but it s always a good manner to keep this rules for better management!

21 Tools - XCode (Interface) 1. Manage connection between Code and UI Inspector - set attributes - linkage of objects - set target - action 2. Show and edit structure of UI Choose *.XIB file to launch Working Area Library

22 ios Simulator ios simulator is a virtual idevice come with ios SDK for you to test your app. Supports both iphone and ipad simulation. Run much faster than Android Emulator. ( You may close it anytime you want.)

23 Create an ios Project Create your very first ios App

24 ios Project - Step 1 An ios project is a well-organized folder (as one project) generated by XCode for ios app development. You may edit, run and export particular ios app within this project. To create an ios project in XCode. 1. You may go to File->New->New Project 2. Alternatively, you choose create a new Xcode project in the welcome dialog box. 3. A new project wizard will be shown.

25 First, ensure that you are choosing Application under ios category. There are various option for creating an app and the most common one and flexible one is Single View Application. Click Next Step 2. Choose type of projects

26 Step 2. Give a name to the project Product Name: Give a name to the project. Company identifier helps Apple identify your app for 1.) Push notification, 2.) In-app purchasing, 3.) Testing and provision. Please it blank temporary. Device Family - set iphone, ipad or Both. Automatic Reference Counting - no more troublesome manual memory management. Next

27 Step 3. Locate your app. Choose a folder to save your app. Tick local git repository for this project if you need source code management. Finish and your app is created!

28 Exploring ios Project Knowing Development Environment and Project Structures

29 Inside ios Project Go to project navigator, take a look at key file types. ios Project packed within a folder. Select this to edit project property Source code - normally one class is composition of a *.h and a *.m files. interface build files imported frameworks, package helps you build ios app.

30 Inside an XIB file Click any XIB file to explore the structure of user interface editor. Owner of the interface file (means source code) Composition of user interface element, you may edit, add or delete any UI element into it. And

31 First Test Run Test your first ios app.

32 Step 1 - Choose build target You must choose the build target, Simulator? Device? iphone? ipad? Go to Scheme menu and choose the correct device. Choose Run to build and run.

33 Step 2a - Testing background process 1. ios supports background processing from ios 4.0 (latest is ios5.0). You may test your app if it has background processing functions or it will perform action when awake from background. 2. Simply click the home button of the app. The app will go to background mode.

34 Step 2b - Terminate testing 1. Normally, ios app would not terminate the testing app when you press home button on ios simulator. 2. You can press stop from XCode. 3. or, you may quit the ios Simulator to terminate the test.

35 Introduction to Basic Objective-C An official language for ios app development.

36 What is Objective -C Superset of C Language C like language with some new syntax support full functionality of C / C++ with ObjC separate header (*.h) and implementation (*.m) files.h defines variable and method..m defines the implementation of method. Memory managed by Automatic Reference Counting (similar to Garbage collection of Java) Single inheritance.

37 Obj-C and C language Common Share the same primitive types: Integer: int, short, byte floating: float, double character: char Simply apply condition statement and repetition statement like java / C for-loop / while-loop / do-while-loop switch / if /? statemnt Same logical operation:!=, ==, >=, <=, &&,, <, >

38 Different from C language In an OOP perspective, not procedural (Works with class). Availability of Anonymous object (id) Way to define a classes Using Message expressions for method call Advanced features (will not cover) Protocol - Delegate ( Similar to Interface in Java ) Block Programming ( function pointer in obj-c ) Category ( extends function of a particular class )

39 Objective-C class Objective-C is an OO language, everything will be treated as a class. A class information is defined in two separated files - header (*.h) and implementation (*.m) files.h defines variable and method..m defines the implementation of method.

40 Defining an objective-c class *.h (declaration) import other frameworks of custom classes here if needed *.m file (implementation) declare class and subclassing it import the definition file declare methods, getter & setter declare variables, object instances within { } pair **all declaration are **all implementations are

41 Defining Methods Defining obj-c method is different from C language, we use message expression to define method. No argument: -(int)add; One argument: input type argument -(int)squareofno:(int)no; <==> int squareofno(int no); Two or more argument: simply treat it as th name of 2nd argument of method -(int)powerofno:(int)no withpower:(int)power;

42 Message (java: function) Message expression [receiver method: argument] Message [receiver method: arguemnt] Selector [receiver method:argument] Method The code selected by a message

43 Method Call Message must be called from a class (a.k.a. receiver ). Receiver will receive the message to execute the instruction written in the implementation file. [receiver message] Java: receiver.message(); [receiver message:argument] Java: receiver.message(argument); [receiver message:arg andarg:arg2] Java: receiver.message(arg, arg2); [receiver message:arg andarg:arg2 andarg2: arg3]; Java: receiver.message(arg, arg2, arg3);

44 Obj-C/Java Method comparison Objective-C ver Person *voter // assume we have this object - (void)castballot; [voter castballot]; - (int)age; int theage = [voter age]; -(Person*)spouse; -(NSString*)name; NSString *name = [[voter spouse] name]; Java ver Person voter; //assume we have this object void castballot(); voter.castballot(); int age(); int theage = voter.age; Person spouse; String name; String name = voter.spouse.name;

45 Defining Methods The method body is the same as C / Java language. has return embrace with { } pair. -(int)powerofno:(int)no withpower:(int)power { int result = 1; for(int i =0; i<power; i++) { result += no; } return result; //return as C/Java }

46 The null object pointer No null in C, so Obj-C adds a nil which means null Test for nil explicitly if (person == nil) return; Can use in assignments and as arguments if expected person = nil; [button settarget:nil]; Sending a message to a nil? Gives no response person = nil; [person doiphone];

47 BOOL typedef When ObjC was developed, C had no boolean type ObjC uses a typedef to define BOOL as a type BOOL flag = NO; Macros included for initialization and comparison: YES and NO if(flag == YES) if(flag) if(!flag) if(flag!=yes);

48 A Relationship - Code & Interface bind call Click to Trigger event TouchUpInside IBOutlet IBAction bind call Controls Event Coding Logic Implementation Layout Design ios uses a special type IBOutlet and IBAction to defines the code is connected with Interface Builder file.

49 Start Coding! Start adding function into your App.

50 In this tutorial Objective: Create your very first iphone Application Understand the use of Tools Connection with IB / XCode Understand the target/action features. (move the slider and see the value change.)

51 Preparation 1. Create a Singe View Application project named SliderX for iphone.

52 A. Define Required UI Element and Methods For user interaction

53 Steps Open the ViewController.h, complete the following code: #import ViewController : UIViewController { Outlet to IB! IBOutlet UILabel* label; } Defined a variable which is a label object for display - (IBAction) means action will be connected to UI element s UIEvent in xib file. sender of the event (the slider this time) Define the method, action for value change event. Defining a class. (Start end

54 B. Construct UI and make connections Establish connection between UI and Code.

55 Steps Open the ViewController.xib file to start the UI editing view. Add the follow UI element from the Library Drag and drop to work area (resize if necessary)

56 Steps 5. Control + drag / right-click + drag a line from File owner from the document windows to the label and click label in the prompted windows:

57 Steps 6. Right-click the UISlider. In the prompted windows, drag a line from the Value Changed event to the File s Owner, and choose SliderValueChanged:

58 Steps Open the ViewController.h, complete the following code: Outlet to IB #import ViewController : UIViewController {! IBOutlet UILabel* label; } - (IBAction) 3. Open SliderXViewController.m, means action connected complete to IB the following code: Implementation of the function -(IBAction)sliderValueChanged:(UISlider*)_slider {! [label settext:[nsstring stringwithformat:@"%.2f", [_slider value]]]; } standard message of UILabel

59 C. Test Your App You know what to do!

60 D. Debugging Find the problem(s) of your app.

61 Debugging Programming is fun. But sometimes you will encounter problems within your app. i.e., Crashes Wrong value shown. Method doesn t call and etc. Different from C, we can t use println to monitor the output of the app. Alternatively, we will use NSLog from Foundation framework.

62 NSLog NSLog is a C function call, call it with NSLog(content). Use NSString before string). Similar to println => NSLog(@ %d, %f, 10, 100.0); NSLog output here

63 Set breakpoint You may set breakpoint to pause the app and investigate app s status at particular line.

64 End. Question? I am looking forward to your great app!